Thanks so much for the video Dave! I'd love to answer a few of your questions: The tweeter is made by Tymphany. I assembled the PCB by hand and the bodge wire was to adjust grounding. The final version will not have any bodges. Op-amp choice. The NE5534 has low voltage noise and is great used with low impedances, but the TL074 has low current noise so is good used with high impedance like these filters. Transmission line vs port. I would say TLs are longer than 'ports' with a proportionally larger section area, are folded and use damping material inside to reduce harmonics of the main resonance. I'm already making improvements to the design for the final version in a number of areas.
Hey Simon, I’ve been exploring the idea of attempting to make desk top t-line enclosure based upon 1/4 wave theory, how ever I’ve been having trouble making the port cross section approximately the same size for the sD of the driver I was looking at, because the mounting diameter and mounting depth exceed alone exceed the port cross section. Is there something that you could point me towards that would remedy this?
@@Gamamaha it's the attitude that bothers me. Who would you trust more? A guy who cuts every possible corner or someone who puts in the 10 minutes extra and does his job with care?
Absolutely awesome, but I do hope you consider changing the 'leather look' covering on the front, and I personally don't like the stands. A smart logo badge would be a great finishing touch for the front. I'll be following you with interest, I want to check these out!
The venting on the back of the driver is for venting the voice coil. A difference between ported and transmission line is that transmission line adds bass over a wider frequency range then ported would.
@@EEVblog Ahh I am with you now I misread it before you mean you filmed extra footage but did not hit record at all on the camera, I thought you meant you had another person doing the filming on your behalf, moving up in the world with your own film crew lol I am with you
AvECAD is also using DaveCAD, hopefully open-sourced by this point.... I almost forgot about BigCliveCAD! Of all three, AvE are the least accurate but most amusing...
I am still using the speakers I built (and more or less designed) myself around 1981. I bought a book at Radio Shack that told you how to do it (there was even math involved) and I used my dad's tools to put them together. Around 2002 the old paper cones withered away so I replaced the drivers with nice modern ones and I replaced the crude crossovers I had built myself with modern boards. They've never sounded better.
The hole also vents the air trapped behind the 'dust cap' (the concave cone effectively acts as a dust cap here) which would otherwise have to pass through the tight slots around the coil, causing turbulent noises and increasing distortion. The grille is just to prevent debris entering the hole.
It’s called a vented pole piece. The pole piece makes up the inner wall of the voice coil gap. Some manufacturers decide to go with the vented pole piece, some choose under spider venting, some choose both and some choose none. The grill is strictly there to prevent debris from getting in and getting stuck in the coil gap. That happens and your driver is no more.
Just woofer. That driver is too small to reproduce frequencies below 60 Hz. And even if it could move the distance required to reproduce those frequencies, it doesn't have enough power to gain them up to where you could hear them.
As an audio DIYer, my thoughts: Those midwoof drivers are A BEAR to work with. To get good low end you need a huge cabinet - at which point you can just use a larger driver with less nonlinear distortion. They also have nasty resonances in the upper midrange that you have to filter out with a more complex crossover to your tweeter. (Somewhat typical of aluminum cones, TBH, but it rains on the "small driver therefore high M/T xover point" parade.) IIRC, they also have a weird impedance curve that makes a passive XO difficult to design - not that it applies in this case. To top it off, the stamped frame is flimsy - I even had one arrive new, pre-bent. Once mounted, maybe that's not such a big deal, but I have a hard time believing it does not contribute to distortion when that cone gets moving - and its excursion (and small light neo magnet) is its point of existence. They can be fun to play with, but there are so many much better drivers out there if you're building a serious speaker. The tweeter, I've heard, is surprisingly good. I have a few to play with but haven't used them yet. They were used by a reputable name in the hobby speaker design circles in an omni-directional speaker design, and were found to be quite pleasant to listen to. In a nearfield or generic BT application, where the strengths of that driver don't apply, I would stick to a typical silk dome - it's better at being a normal tweeter. Dayton has some 1/2" to 1" domes that are a complete steal at their price. So overall, I feel like this design is a checklist of engineering experiments, not necessarily a great design in and of itself. Most DIY speaker guys go through something like this because it's unusual and therefore interesting. But it's unusual because many of the tried and true designs are just better suited for general use. There's always a fascination with making the smallest cabinet possible as well - but physics wants a Cerwin Vega floorstander, and clever engineering can only get you so far. Second best, for "good enough" cases, is a stout small driver with tons of DSP. Everything else is a compromise.
I'm not normally negative on other's designs, but those traces! I would have a fun time going through the board layout and putting a chamfer/45s on those right angles.
It doesn't actually matter for anything besides high voltage. Here's a good stack exchange answer if you want to know more about why that is: electronics.stackexchange.com/questions/226582/pcb-90-degree-angles#226693
Although the full-range driver can be used without a tweeter, it will become more directional as the frequency increases making essential that you be directly in front of them to hear the full range. By crossing over to a tweeter, you can avoid that beaming effect.
Putting the price aside, I wouldn't use these for any critical listening, only for checking mixes. These drivers are too small to have a much wider frequency response without using tricks. Also, these would not work well for surround setups either, as you have to use them as a pair. No monitor in that price range has a slave passive speaker. They all have their own preamps and can be used by themselves, so you can buy the monitor as a single unit for surround setups. Also...if the monitor is that flat as claimed, why the plots are shown with averaging and with the large division of 20 dB per octave? Just give the full frequency response of the monitor.
Vishay caps are quite good actually. We use their tant's at my work for making all our RF boards and Vishay is prime spec with no allowable sub's b/c of the strict temp. profile the systems is designed and tuned to operate in.
That Dayton driver is a series piece. All you need to look at is the huge buna-n surround, huge magnet and then that deeply pleated nomex spider and a stiff cone. Seeing the nomex spider did it for me. If they are specing a nomex suspension, then they put the money in the right place.
It is a Dayton driver but to be fair they totally ripped off the design from AuraSound. If I knew that when I designed them I would have gone with AuraSound on principle, but the small differences make it difficult to change over now.
This is definitely not a transmission line - the port is way to short. For a tuning frequency of 70Hz (like the frequency response suggests), the line would have to be about 120cm long. It´s a ported enclosure - which isn´t bad...just don´t call it a TL.
I'm stunned at the amount negativity towards a product, which by comparison to far eastern standards is very high quality. The number of comments that say they could build them for $100 is shocking. This of course is a complete impossibility, especially if they are to sell them at a profit and stay in business. Ok the design of the PCB could be better, with more care taken with the layout. But in low frequency applications, it really makes little difference to the way the circuit functions. These are also pre-production samples, so there's going to be some elements of the design that won't get into the finished production models. So can we stop with this "I could build them for 100 bucks" bullshit, because you can't period. If you can, then do it and send them to Dave for evaluation.
I don't know a whole lot about the pcb, but the speaker itself is definitely not worth anything above 100. The drivers I'm 99% certain are Dayton Audio which I'm seeing for about 25 euros a piece and the "tweeters" are even less than that. edit: after watching more of the video I can confirm they're indeed the Dayton Audio ND91 woofers.
This could transition to a premium product with proper QC(the manufacturing tolerances on this thing.. lol), PCB design, and better external design. It looks like a late prototype, or a personal project.. This is not something you sell at +200% premium...
They might have a clever transmission line design, but ultimately the speakers are coupled to a single amplifier (bad, despite the recent trend for "powered" monitors to do this), that's based on an off-the-shelf amplifier IC (still not ideal), use stupid connectors (sorry, but it's true), and individual drivers that are more at home in a TV sound bar than a NFM. And let's not even start on that hazard of a power brick - at least get something vaguely serviceable from LiteON, Delta, or even Mean Well. They aren't near-field monitors, but a pair of $250USD Wharfedale Diamonds will run circles around these for build quality. And they're made in the far east! It's some of the claims that annoy me most. 4x50W? Not a chance. Class A/B IC better than Class D? Nope. Alternatives using "inferior particle board"? AFAICT, the "research" suggesting this is 40+ years old - before many modern materials were even widespread - and most speaker manufacturers (even high end) use MDF because it's easier to build precise cabinetry with and does not sacrifice sound quality.
That heat sink on the back should be mounted with the fins running top to bottom. Cooling will be compromised the way they’ve done it. At 15:20 it’s obvious the rear panel seal is only fitted down the sides, not the top and bottom. That could cause a few problems with the sound. They should be completely airtight except for the transmission line port.
Thanks for that point, Ill see if I can source a heatsink shaped so the fins run vertical, but I do need to work with what's available. Really no problems with heat as they are though. P.S the green is just a liner on the seal tape as it's sticky and will gunk on the case otherwise. I've not seem it come of like that before, maybe something to do with being in air freight.
Simon A - Bear in mind that your speakers could end up being used in temperatures you may not have anticipated! You ideally need a large safety margin to cover that. Of course, if the user sideways mounts them...! :-).
these are NOT MLTL speakers and the drivers do not appear to be high quality. Notice how none of the driver specs are given here or on the kickstarter. Go to partsexpress.com and you can build your own bookshelf monitors with an active crossover and add a blutooth module for a fraction of the cost. The $100 mark is not far off depending on how good of a crossover you want to build. Also, anyone that knows about resonance understands that for the density to mass ratio and quality control of the product, MDF is a better choice for cabs than plywood unless he is using the finest grade cabinet ply (9 layers or more) and checked for inclusions in the cab. This is a set designed for the recreational person who likes to think they know about something because they screwed nut A into hole B. Just an FYI, I built 3-way MLTLs as my main fronts and the crossovers in them were $300 so please do not mistake a product produced for noobs for quality just because the uninformed think it is.
I've spent my life fixing Pro audio and lighting and for the most part they work. Right angle tracks aren't an issue at those frequencies. As for recording, Doug Ford will tell you the same thing. If a producer can mix a track and make it sound good on crappy speakers, it will sound great on real ones. This does not work the other way around!
Right angle is considered bad practive as acid can pool there and give irregular track width... but it's not an issue with minimum 0.01inch tracks and modern production.
@@trophospherecrappy speakers is how you lay down a track properly. Two enormously popular studio monitors were the YAMAHA NS10 and the Auratone 5c. Both were bloody hideous and you wouldn't wish them on your worst enemy but you mix sound to be played back on crappy systems. No point mixing to sound good on proper set of drivers when people listen to it most on TV. Always lay down tracks for the worst systems, not the best
@@raykent3211 nearly 30 years in this industry. Seen hundreds upon hundreds of studios an oh yeah, my daughter is one of the most famous producers and faces in Asia... Who cares about some orchestra?
IME, the tweeter is what usually fails before the main driver. If the tweeter is not replaceable without destruction of the cabinet, these will become throwaway.
The midwoofer is a reputable unit, but I don't know about the tweeter in the LBM's. They look like they are 1" Tymphany wide-range speakers, kind of like the Harman Odyssey single-suspension mid-tweeter speakers, so they probably aren't "junk" but I haven't heard them sound better than actual edge-driven dome tweeters in my experience. A "transmission line port" was originally done by Irving "Bud" Fried back in the 70's; my parents' old Fried Model Q monitor speakers had them, and they were called a "line tunnel" - effectively they are a lossy port, also called an "aperiodic" port. You actually lose a small amount of deep bass from this approach but you can flatten out the impedance peak of the woofer which makes them a better load for tube amplifiers with their higher output impedance so that the load the amp sees is less reactive. The Scan-Speak Scan-Vent and the Dynaudio Variovent are similar in practice. AudioSmile has been around this block before with some passive monitors using reputable drivers from SEAS in Norway, using passive crossovers.
They are amazing little 'tweeters' (quotes because they have far wider range and excursion than a typical tweeter), performance well beyond the competition that look similar. But what would you expect from Tympany who oversee Scan-speak, Vifa, Peerless etc.. You could easily call them a damped folded slot port. Transmission Line sounds cool though and it's quite a reasonable description. The primary goal of the damping is to reduce harmonics of the line, rather than flatten impedance at least in my design.
It's stupid of course, but after multiple recodings, improvised test set-up and my poor speakers and ears the Little British Monitors sounded more natural and with flatter response.
Back in the 70's I read an interesting article about doppler distortion in wide-range speakers. In fact you will have a moving sound source when playing, for instance, a 5 kHz tone on a membrane that moves with a lower frequency like 50 Hz.
@@PileOfEmptyTapes Also the reflections from the voice coil around the tweeter can cause 'blurring' to transient response. Philip Newell has an interesting chapter on this in his book Recording Studio Design where he measures Tannoys.
Aviation or otherwise... a GX-16 is in fact a DIN Connector and seriously though, did you think that you were going to teach dave a thing or two with this comment ? all you've done is shown how silly you can be i suppose , next, you'll be telling me that an RCA Connector is not RCA , but it's actually Composite hehe Mate, just keep it simple ok, we all know what we are talking about
Never heard anybody calling a connector like that DIN in Europe or in USA. DIN connectors in popular parlance are those 13.2mm circular affairs with thinner pins well known from old receivers, cassette decks, and MIDI interface boxes. Not used anymore in Hi-Fi except in Naim Audio gear. DIN is the German Institute for Standardization and I don't know if there is any number ever issued for GX series from them, but those aviation connectors look more like MIL-Spec USA Cannon stuff or alike. Probably very old. In any case I did not try to teach Dave anything, only to remark that those connectors are not called DIN for very many other people, especially when met on audio equipment. Regards.
@@somebodyx it's like people calling one of the power connectors inside a computer "a Molex" and they don't realize that most of them are Molex. They think "a Molex" is a specific plug. They say things like, "plug in the Molex, "referring to a single specific plug. Same with DIN.
@@Audio_Simon And here was me thinking "CB Mic connectors" Have a good christmas, I personally like the fact you're here to answer questions and have taken stuff on board. Any chance of doing a version without BT? (not just to please Dave, but I've known BT modules cause horrible interference even with a well filtered separate power supply
@@davidf2281 Some kinds act like varactors, causing all sorts of undesirable effects to the signal. A test with a spectrum analyzer will show if there really is a problem.
I've heard these a few times and it's important to put them into context - for current use and the history behind the design. They are designed to be flat and accurate, a monitor speaker and therefore somewhat at odds with the norm for small multimedia speakers which are often hyped in the presence region to give added bite and excitement, and boosted in the upper bass for additional thump. Such anomalies sound impressive on first hearing but can become tiring after extended use, not to mention you are overlaying a set of defined tonal characteristics onto every performance. The LBM tries to avoid this by remaining clean and neutral. The ply cabinet is better damped than many other materials, lacking for example the high Q ringing often found in MDF and some plastics which colours mid range frequencies. I'm sure Simon could make these more cheaply with MDF, and even save some time on machining and finishing - but they'd sound worse.
Its safer to orient the heatsink like this when they are big enough to work that way, because when the speakers are oriented sideways - no nasty surprises. That heatsink doesn't look very sensitive to orientation anyway, the fins are widely spaced and shallow.
@@adymode But they are not designed to work on their side, did you not see the accompanying stands in the first couple of minutes? I've done flowtherm modelling of heatsink orientation and the relationship between fin spacing and height. I doubt given the small amount of total power dissipated.
I still think these "chip amp" are all to often overlooked. I've run a DIY LM3886 amp for around 8 yrs on a set of floor standing TL speakers (DIY of course) they rock for the cost and are great little projects. Currently have version 2 in the pipeline.
What really puzzles me is how it can be designed with different high frequency dispersion patterns between the left/right channels. The way the acoustic lens on the tweeter is implemented is really wierd.
Venting the magnet reduces first resonance frequency, not unexpected in a smallish wideband driver (headphone drivers often do the same). Good attention to detail in construction, parts appear to be nothing earth-shaking but of decent quality. (Yeah, the heatsink could be better, but eh... it'll do.) The speaker link jacks look like those used for radio mics to me... 4 contacts are just what you need for two drivers. Looks like single supply for the main power amp and split supply for the preamp stage, I wonder how this goes together... center-tapped AC input with 1x bridge rectifier + 2x half-wave? Pricing is not budget basement, but I mean, these are made in moderate numbers in the UK, not cranked out by the thousands in China, so both economy of scale and labour costs would be working against them.
So, some thoughts on the review. Quite right to be dismissive of the cabinet being a real transmission line. A few have already noted this. The original "transmission line" design went back to Bailey, and was a design with essentially no theoretical underpinning. The idea was that the stuffed tapered line would adsorb all the energy off the rear of the driver was a nice idea, but the reality was always going to be something else. There is now quite good understanding of what is really going on, and a few useful design tools available, Martin King's work probably being the definitive, although tools like Hornresp can also model the system and get much the same results. What the enclosure seen is is a tapped line. The port is coming off part way down the line, and you will get a reasonably complex system. There will be a resonant system in the box with the speaker, and other in the box with the electronics, they couple, and there is a lossy resonant port. Add to that a quarter wave resonant system end to end. However, what you can do is tune this mess to produce a range of responses, and with care eventually end up with a flat response. For a small enclosure you might be able to create a more satisfactory (for some definition of satisfactory) result than a simple sealed or ported alignment. On the subject of full range drivers, an eternal problem with any full range driver is the polar response at high frequencies. As the driver becomes large relative to the wavelength the speaker becomes quite directional. Whilst it is possible to make a flat response on axis, the frequency of the energy in the diffuse field is heavily skewed. Metal cone drivers invariably have a few quite nasty resonances at high frequencies, and part of the art of crossover design is to avoid energising them. All full range drivers, no matter what the technology, have significant resonance issues. One notes that the bass drivers are about 40 USD each, and the tweeters are probably in the vicinity of 10-20 USD. So the BOM for just the drivers is already 100 USD. Cutting out the enclosure on a home gamer CNC router is not going to be conducive to a cheap result, even if the kit probably goes together with the precision of a Swiss watch. The driver selected seems pretty nice. It has such nice design features as a shorting ring around the voice coil, and has clearly been carefully optimised. It is great for a small 2 way. One notes there is a subwoofer output. Does using it place a high pass before the bass drivers? Using it with a subwoofer would help greatly with reducing the excursion the drivers need, and would probably drop distortion quite a bit. With Dave's experience in building stuff for manufacture, some comments on the expenses, and the margins would have been illuminating. Despite the apparently high cost of these speakers, and the moaning, it is not clear how unreasonable the price is. Without serious economies of scale, getting prices down is hard, and in the end, it isn't the ingredients alone that matter. If the final result is good, that is what you pay for. The modern world doesn't seem to value the work in getting it to that point, and expects the IP for free.
Like electrical transmission lines, an acoustic transmission line is supposed to present the driver with a constant, characteristic, impedance. I doubt that is what this one does, and even the best ones, on a proper scale, fail. They aren't really supposed to output anything at the end, and I have never fully understood quarter wave transmission lines because they never add up to Unity. In contrast, a ported cabinet presents anything but a flat impedance to the driver. It's essentially a second, lower, resonance below the driver's main resonance which serves to extend the bass response. (You don't get two peaks as one might imagine, but get a smooth shape if properly designed.) The price you pay for this is a sharper rolloff because you have introduced two new poles; in the mass of the air and the compliance of the air in the box. They are very different things indeed. I hope I have elucidated the difference.
Transmission line converts the sound waves from the back of speaker and changes there Phase so instead of cancelling out they add to what is coming out the front of the speaker.
i use those switches(power) in my detectors, and there is a low profile version that if used in this would mean it didn't need those wire links on the power socket, the power board could be soldered flush.
Being transmission line, you’ll have a bit lower bottom end, which is good, given their size. Also, your mid/low driver will have more freedom of motion, if he properly tuned the transmission line.
I really like BC caps(and Vishay branded plastic ones). Electrolytics are most of the time quite a lot cheaper here in EU than comparable series japanese ones. Nice to see them used here.
My biggest issue with the speakers is that they do not have balanced inputs. Most professional studio monitors have balanced input through XLR connectors
As a line array of small drivers those woofers do work pretty well. You need 30 of them to get a decent bottom end and usually in an infinite baffle configuration. 30 x 1" ports equals a 30" port. Equally those 3½" drivers add up in surface area quickly too. For those drivers to be effective they have to be used in something like a Bose 509 configuration. As for the unpopulated area of the board, I have a hunch that it was for a USB DAC which ironically would have been better than the bluetooth save for the wireless part. You also may want to work the drivers in before you pass judgement. Often the compliance of the driver increases over time. It's like a leather wallet that needs to be worked in a bit before it feels right. I got a set of these and honestly they don't compete with my JBL 4312g but they are rather impressive for the size. Their heaps cheaper too for the level of audio quality possible with these.
I might be missing something here. On the website it states the power output is 4 x 50w, but the power supply is 6A@15v which equates to 90w. So how the hell can you get 200w power out from a 90w power supply ? - do those flux caps double up the power :) I'm also no expert, but for the money there are better finished speakers out there. He could have added a veneer to the front edge rather then leaving it exposed plywood.
Well, fortunately(?), music is far more dynamic than a constant sinewave, so there's some so-called "crest factor" involved (ie. the power supply won't need to supply 200W all the time). That being said, the power brick sends shivers down my spine. Pretty sure it's light as a feather, and even IF it meets the specs on the label (briefly as it might), it's still no less of a death-trap (like pretty much all those cheap-arse "replacement" laptop power bricks).
@@MalcolmCrabbe Well, there's that, plus the fact that the output power's directly related to the supply voltage. Right on the first page of the chipamp's datasheet, it says "4x 30w / 4ohm @ 14.4v", and that's at 10% THD, so well into clipping territory. Pretty standard rating tactic to inflate the numbers. Figure 9 on page 11 of the TDA7850 datasheet is probably more telling. Assuming no voltage sag, at 15v you'd get a bit under 25w into 4ohms "clean enough" (1% THD). I wonder what those 120uH inductors near the output are actually doing there, if the crossover is done at the line-level, ahead of the amplifiers. Maybe an RLC notch, to minimize that ~8kHz peak (break-up node) in the "woofer"? See the link for reference: zaphaudio.com/audio-speaker18.html
Not a fan of controls on the back of the monitor. A small box for the amp and the controls would have been better. Would have also resolved the dissymmetry. But good on him anyway.
You're not supposed to change those settings all the time on actual monitors. You set them once and your mixer/audio interface controls the gain for both after they're set.
Hmm, likely Baltic Birch (aka Russian Birch) so there are more lamination and less voids then normal 1/8" laminated plywood. Just me but IMHO it would have been better to edge trim the wood though... Cheers, - Eddy
Why the Bluetooth hatred? I'm gonna bust out the oscilloscope and test this! Disclaimer: I don't necessarily like Bluetooth. It just works faster than most Wi-Fi devices, so it wins by indirect default.
Maybe "balance" the left-right volume by putting a Lithium battery in the second one to provide not just offline power but to reduce the size of the mains brick to deal with only the average power.
The reason why people don't do these kits anymore? Because there is no profit on it unless you ask a ridiculous price like these. I know pretty much which drivers are being used. At my company we sell something similar monitors for just around 80 bucks. And those are sold per around 500 per year. I am far from impressed for the amount of money
@@uK8cvPAq . That's difficult to calculate. What i see a lot with amateur kickstarters is that they don't use the right sources. So they pay full price for their parts. So in the end the customer pays for the fact that they don't have their suppliers and calculated labor right. We can get these drivers for less than 10 bucks. But it's not the whole story. It's about what is available on the market for the same price and what your story is to make up the higher price. For 300 pounds you can get something that is far more professional and better quality. Like orders of magnitude. A big manufacturer (selling like hundreds of thousands or millions) would be able to make this for just around 30-40 bucks maybe.
@@Audio_Simon I think you're asking for a brand? We don't sell speakers ourselves for consumer market (only for pro-audio). But we do deliver the technical side of it (engineering design, hardware and parts). There are a lot of (known) brands that don't do the engineering themselves, the engineering is done by a 3rd party. In our case we sometimes even do production and assembly for those brands as well. (yes technically i know I said that we sell them in the first response, but just to make the story a lot less complicated) Obviously for confidential reasons I can't tell which brands those are.
I think the holes in the back of the woofer are a cooling port, I think you were mistaken about the sound going through the foam, the sounds goes past the tweeter to the top of the speaker then into the wave guide thing
Swan makes a 3-way speaker kit for $290 on Amazon that you assemble the enclosure and the passive crossover. They are passive so you will need an amp, but reviews say they sound great.
I don't like them... Someone made these and think they are nice and are proud of them - I respect that, but I don't like them at all myself. Cable between the speakers is not my thing either, but dude Dave - these speakers are so small - you will *never* be able to hear any difference between the active and passive box. No way. Unless there is something wrong with it. Potential loss? In this specific case, that's moving into the audiophoolery domain :P. These might be fine as speakers on your computer desk, or even as speakers for the TV, but would I put them in my audio studio? Nope. That's not what these are built for - but they certainly price them and name them to sound like they did. Nope!
at that price I wouldn't even put them on my desk for my computer. 630$US without the stand. For that price I'm sure you can found a nice used pair of monitors from a well known brand that have some reputation. So for personal use? lets just say you can buy some nice used quality HiFi from the 70's that have that nice warm sound from that aera. Even brand new 630$US gives you a lot of room to built yourself a nice speakers+amplifier couple.
@@blackdevil72 yes. I agree. This would not be my choice at all. I forgot, did Dave say it was a kit? In this case it is totally not worth it. The wood case, you either build one yourself or you pay a factory to churn them out for u. U don't wanna pay for a guy using a toy CNC to manufacture them at home. Unless its special and real fine work - but with all due respect for the creator - this is not worth it by the looks of it.
@@LifeOnHoth Dave said it was a kit and from kickstartter the kit is still 525$US. After having seen one video of some one building them, its not that the kit is hard to assamble but if you do something bad you have a pair of 500$US paper weight. So depending on the quality of the assembling two person won't have the same sound. And I'm not just alking about hability to follow instruction, depending on how wood glue dry you could have small air leak. Plus a little thing I don't like at all and where the guy is a genius he only sent pre-production PCB to group of youtuber and all of them gave him a pass because "oh yeah look like pre-prod, nothing wrong with it, but I can't really judge the quality but over all its good, you could buy them". There is no waranty on the final product, every video I've seen was with a pre-production model. So close to the end of the kick start and he can't show at leat one "finished" productt to the one guy he have sent the assembled kit? Now I'm not sure if I'm clear but that price for so few waranty? I'll pass even if they sound good.
@@blackdevil72 Yeah... that was kinda my idea also... that if this is a kit like you describe it - the price is just all wrong. This price will get you professional active studio monitors. With warranty, with psu and amp in both cabinets and most important - bigger. Imho - if u go under 5 inches bass element, that's simply not worth the money if u aim at a pro monitor use. I'm sure as speakers for your PC or TV they will be fine, but of course the price is all wrong for that. I have actually spent some years doing professional wood work many moons ago, and I would also be concerned that if you get those plywood sheets in pieces, about getting it properly joined - though it is not hard, it needs to be done properly. All in all - basically a worthless product on the account that it totally misses the mark. It's either this or that. :--)
Back in 1973 a coworker and I working at HP in Colorado Springs, CO started an audiophile speaker company, (Green Mountain Audio,) that is still in business 50 years later. So I know a bit about speakers, and can confidently say to your subscribers that so do you. Cheers.
The very best thing for speakers is MDF or HDF not plywood... it’s pretty simple, the heavier and more dense the material the better, the goal is energy absorption... and plate metal on the back is not great... flat amplitude response is great, how about the phase? You can EQ any system ‘flat’ and it will sound horrible... it’s much more about phase and the lobes in the off axis pattern...Their is no real difference in types of tuning, a port is a port, unless it’s horn loaded. Also the foam used is to increase the apparent enclosure volume by keeping the thermal load constant (isothermal), pretty sure that type of foam is not correct. Anyway it’s nice to see young folks experimenting with this stuff, unfortunately MP3 pretty much killed off HiFi simply because it’s an easy to use format, it’s incredibly difficult to find high fidelity signal sources these days.
I owned some Ohm Walsh 2's with transmission line drivers and port. Very good sound reproduction and very pleasing to the eye. Don't thin I could fit them anywhere these days.
I think they sound a lot alike, but the Focal ones are a bit crisper on the treble... Depends on which you consider more accurate. I assume neither has base.
Transmission line ports aren't always better than typical ports, but in cases with small woofers they often times are. Ideally, the area of a T-line port should be the same as the moving cone area of the woofer, and the length of the port (in combination with the area) determines the lowest tuning of the enclosure. Similar to a clarinet, trombone, or really any other instrument, the length of the port in a T-line enclosure determines its lowest frequency, or in this case, it's cutoff frequency. At 3:40 you said that Simon mentioned that it's harder to make T-line enclosures for smaller speakers. I really don't understand where he's coming from with that. From my experience, it's much more difficult to do T-line enclosures with larger speakers since they require much more area for the port and end up taking a lot of space. Whether they're large or small the math is all the same, but maybe I'm missing something.
Seven hundred u.s. dollars for an amplifier with 10% distortion? Aptx and, aptx hd especially, make a difference in sound quality but any efforts at sound quality are negated by that horrible amp chip. The whole thing seems to be put together from internet research by someone who doesn’t really have an interest in audio quality. In sourcing parts for my own build of a bluetooth speaker into a vintage boombox I’m acquainted with all the components used here and there is a definite mix of good and cheap components. The “tweeter” is most likely another full range speaker. True tweeters are built with sealed backs and wouldn’t need their own enclosure as was done here. The build is incredibly amateur or intentionally cheapened to make the most money. Dave went easy on the guy.
There is no problem with that power connector or ribbon cables for audio. I agree that these speakers are overpriced and there are many things wrong here, but there is absolutely nothing wrong with the things you point out from an engineering point of view.
@@colinedwards7250 The audio signal is low impedance (line level) at that point so is not really susceptible to interference. I'm sure that connector is just fine for 6A. Again, there are things wrong with the design, but the things you're pointing at are not.
@@colinedwards7250 What i'm more creeped out by is the power supply itself - that thing is a potential death-trap right there. Those [ahem] "replacement" power bricks damn near need a paperweight so the wind doesn't blow'em away, and i wouldn't trust the ratings on the label as far as i could throw'em.
So one monitor, with an external speaker. I think I would prefer a small shielded box with front controls and rear I/O with two external speakers. You could also design a matching stand for the amp box. Who is it aimed at? I am supposing PC speakers for those with space issues?
Hi Dave, here in Britain, our houses are 35% the size of the rest of the world. Thus we are also 35% shorter, and out speakers come in smaller sizes... /s
Transmission line speakers should be totally non resonant.. Start out with the square footage of the "pipe" being a fair bit larger than the active area of the speaker.. (fair bit of geometry there..) a 10 inch woofer would start out at about 80-90 square inches..that will taper down to the active area of the woofer at the exit. Built a number of them over the years.. the drivers have to be selected for the job to get good low end response.. I measured my 4' tall designs with a 10 " woofer solidly flat down to below 50 Hz...Fed with a fairly decent little amplifier setup...The transmission line (the "tube" needs to be carefully filled and packed with long fiber wool... hung lin small baskets. You tune the speaker by changing the packing of the wool.. and they are all different.. (Lots of particle board for the walls to keep it non - resonant..)
So what is the problem with right angle traces? I know from my kicad class in college that you're not supposed to use them, but I never remembered to ask why.
Just get a junk circuit board, hack it to size and install it in the passive speaker to approximate the presence of the active board in the other speaker. :)
Been a while since I've seen anyone dabble in transmission line enclosures. I believe they were also called an acoustic labyrinth, requiring multiple baffles combined with a specific weight and volume of damping to slow the rear pressure a full wavelength instead of the half-wave of a tuned port, resulting in a flatter response and without the common 'muddy' sound of the latter, the reason acoustic suspension has superior phase harmonics. Bose has produced a few models featuring these types of enclosures, and I remember someone years ago using plastic conduit to create some Dr. Seuss arrangements for the same effect. Good stuff as usual mate! ~A. Lurker
@@vanjazecevic1159 The first ones I'm familiar with were university prototypes from the 1970s, and the labyrinth was 100% filled, with longhair wool fiber, weighed to produce a more true TL than the half-filled 1/4 wave variant. Approximate dimensions were 5'H x 4'W x 4'D.
IamIUareU It's supposed to be for the other parts and the acoustic design work, not the stuff on the PCB, though at least that circuit hasn't been price optimized to death with bad caps and knock-off chips.
@@johnfrancisdoe1563 he is selling nationalism and patriotism, not quality product (in any way, just as Dave said and confirmed)... otherwise he could pay $1000USD for freelance electronic engineers to design him high quality electronic scheme and design, then he could produce it also with high quality in China and could employ UK Q&A before he shipped the product and would get a really great quality product that would cost way less... Dave did the same (altho he got the design and production for free i think), ask him if his multi meter is high quality and bang for the bucks...
@@Hobypyrocom A lot of EE are terrible at audio circuit design to be honest. This is low frequency stuff, but signal integrity is everything, not getting a pretty layout with neat traces that cause crosstalk and inductance. Many immediately opt to using a ground plane which is also terrible for audio. My PCB may not be the best looking but it works well where it matters. Regarding making it in China, you've got to realise this is a small production I'm not looking to flood BestBuy.
@@Audio_Simon "A lot of EE" is not equal to all of them... i know some guys that are really cheap and great designers... most of them also dont charge you if you dont like what they designed... the ones i know provide a working prototype included with the design, so you can check first what you will get. if you write a detailed documentation with your requirements, even those who are terrible at audio circuit design will provide you with decent product. "you've got to realise this is a small production" yes, i am aware of it, but who said that if you produce it in China you have to make millions of pieces? it will be more expensive for small quantity for sure, but again it will beat the price of UK manufactured guaranteed... think big and aim for the sky, you have a great idea that has huge potential, but at the moment the execution is bad... good luck and best wishes...
@@Audio_Simon Then send those to an EE who is a professional in the audio field, like Doug Ford, who has worked with RODE for a number of years and could test your monitors properly. Anyone can claim EE are terrible at something without subjecting themselves to the same scrutiny. Put your money where your mouth is.
Thanks so much for the video Dave! I'd love to answer a few of your questions:
The tweeter is made by Tymphany.
I assembled the PCB by hand and the bodge wire was to adjust grounding. The final version will not have any bodges.
Op-amp choice. The NE5534 has low voltage noise and is great used with low impedances, but the TL074 has low current noise so is good used with high impedance like these filters.
Transmission line vs port. I would say TLs are longer than 'ports' with a proportionally larger section area, are folded and use damping material inside to reduce harmonics of the main resonance.
I'm already making improvements to the design for the final version in a number of areas.
Hey Simon, I’ve been exploring the idea of attempting to make desk top t-line enclosure based upon 1/4 wave theory, how ever I’ve been having trouble making the port cross section approximately the same size for the sD of the driver I was looking at, because the mounting diameter and mounting depth exceed alone exceed the port cross section. Is there something that you could point me towards that would remedy this?
Please fix the pcb traces, it's horrible.
@@billigerfusel Well, it looks horrible, yes. But for such low frequency stuff, the PCB layout doesn't really matter.
@@Gamamaha it's the attitude that bothers me. Who would you trust more? A guy who cuts every possible corner or someone who puts in the 10 minutes extra and does his job with care?
Absolutely awesome, but I do hope you consider changing the 'leather look' covering on the front, and I personally don't like the stands. A smart logo badge would be a great finishing touch for the front. I'll be following you with interest, I want to check these out!
The venting on the back of the driver is for venting the voice coil. A difference between ported and transmission line is that transmission line adds bass over a wider frequency range then ported would.
No tweeter on the face of this planet is able to reproduce the frequencies of Dave's voice.
Love the main Cap labelled as Flux Capacitor
Dave seems to have missed that as he didn't comment on it in the video.
@@kevincozens6837 Yeah missed it twice once during filming and then editing
I did shoot video footage of it and other stuff, but didn't press record, see my twitter post
@@EEVblog Ahh I am with you now I misread it before you mean you filmed extra footage but did not hit record at all on the camera, I thought you meant you had another person doing the filming on your behalf, moving up in the world with your own film crew lol I am with you
@@EEVblog ok. I would have checked the post but I don't use twitter or have any interest in it.
Produced in DaveCAD - Unlicensed Version. :D
AvECAD is also using DaveCAD, hopefully open-sourced by this point.... I almost forgot about BigCliveCAD! Of all three, AvE are the least accurate but most amusing...
Explains the bodges and wierd angles on traces. You only get the good stuff when you pay for it.
Yeah, I just noticed it LOL
i'm still confused as to why DAVE CAD is mentioned on a PCB that dave didn't create ???
NiHaoMike No, that's a pirate version, the genuine version is on Github: github.com/EEVblog/DaveCAD
I am still using the speakers I built (and more or less designed) myself around 1981. I bought a book at Radio Shack that told you how to do it (there was even math involved) and I used my dad's tools to put them together. Around 2002 the old paper cones withered away so I replaced the drivers with nice modern ones and I replaced the crude crossovers I had built myself with modern boards. They've never sounded better.
I'm on old Acoustic Solutions speakers, when you have quality stick to it.
10:26 Dave missed his own Easter egg.
"Produced in DaveCAD - Unlicensed Copy"
Hi dave, the grill is to cool the voice coil down.
When the subwoofer moves it blows air in and outside the little hole, cooling down the voice coil
Ah, makes sense.
@@EEVblog you're welcome :D
The hole also vents the air trapped behind the 'dust cap' (the concave cone effectively acts as a dust cap here) which would otherwise have to pass through the tight slots around the coil, causing turbulent noises and increasing distortion. The grille is just to prevent debris entering the hole.
It’s called a vented pole piece. The pole piece makes up the inner wall of the voice coil gap. Some manufacturers decide to go with the vented pole piece, some choose under spider venting, some choose both and some choose none. The grill is strictly there to prevent debris from getting in and getting stuck in the coil gap. That happens and your driver is no more.
Just woofer. That driver is too small to reproduce frequencies below 60 Hz. And even if it could move the distance required to reproduce those frequencies, it doesn't have enough power to gain them up to where you could hear them.
As an audio DIYer, my thoughts:
Those midwoof drivers are A BEAR to work with. To get good low end you need a huge cabinet - at which point you can just use a larger driver with less nonlinear distortion. They also have nasty resonances in the upper midrange that you have to filter out with a more complex crossover to your tweeter. (Somewhat typical of aluminum cones, TBH, but it rains on the "small driver therefore high M/T xover point" parade.) IIRC, they also have a weird impedance curve that makes a passive XO difficult to design - not that it applies in this case. To top it off, the stamped frame is flimsy - I even had one arrive new, pre-bent. Once mounted, maybe that's not such a big deal, but I have a hard time believing it does not contribute to distortion when that cone gets moving - and its excursion (and small light neo magnet) is its point of existence.
They can be fun to play with, but there are so many much better drivers out there if you're building a serious speaker.
The tweeter, I've heard, is surprisingly good. I have a few to play with but haven't used them yet. They were used by a reputable name in the hobby speaker design circles in an omni-directional speaker design, and were found to be quite pleasant to listen to. In a nearfield or generic BT application, where the strengths of that driver don't apply, I would stick to a typical silk dome - it's better at being a normal tweeter. Dayton has some 1/2" to 1" domes that are a complete steal at their price.
So overall, I feel like this design is a checklist of engineering experiments, not necessarily a great design in and of itself. Most DIY speaker guys go through something like this because it's unusual and therefore interesting. But it's unusual because many of the tried and true designs are just better suited for general use. There's always a fascination with making the smallest cabinet possible as well - but physics wants a Cerwin Vega floorstander, and clever engineering can only get you so far. Second best, for "good enough" cases, is a stout small driver with tons of DSP. Everything else is a compromise.
I'm not normally negative on other's designs, but those traces! I would have a fun time going through the board layout and putting a chamfer/45s on those right angles.
It doesn't actually matter for anything besides high voltage. Here's a good stack exchange answer if you want to know more about why that is: electronics.stackexchange.com/questions/226582/pcb-90-degree-angles#226693
It looks just bad. No excuses!
Although the full-range driver can be used without a tweeter, it will become more directional as the frequency increases making essential that you be directly in front of them to hear the full range. By crossing over to a tweeter, you can avoid that beaming effect.
As an audio pro I can tell you your comparison setup with the mic was better than most pro audio comparison videos. Good call
They look like nice little speakers but the price is over the top. It would actually be cheaper to make your own.
Putting the price aside, I wouldn't use these for any critical listening, only for checking mixes. These drivers are too small to have a much wider frequency response without using tricks. Also, these would not work well for surround setups either, as you have to use them as a pair. No monitor in that price range has a slave passive speaker. They all have their own preamps and can be used by themselves, so you can buy the monitor as a single unit for surround setups.
Also...if the monitor is that flat as claimed, why the plots are shown with averaging and with the large division of 20 dB per octave? Just give the full frequency response of the monitor.
Vishay caps are quite good actually. We use their tant's at my work for making all our RF boards and Vishay is prime spec with no allowable sub's b/c of the strict temp. profile the systems is designed and tuned to operate in.
These ones are great, and good value too. Lifetime is rated as 6000hours @ 125C. Better than even Panasonic FC series.
Red painted screws, what kind of arbitrary expectation is that?
Makes them go faster, dummy
Anodised please, none of that painted rubbish.
@@EEVblog low profile as well...
Got to say the beech plywood does work well for diy speakers. I build them like this all the time!
Baltic Birch lacks the mass and damping characteristics of the acoustic plywood used by amateur builders in the 1950s and 60s.
That Dayton driver is a series piece. All you need to look at is the huge buna-n surround, huge magnet and then that deeply pleated nomex spider and a stiff cone. Seeing the nomex spider did it for me. If they are specing a nomex suspension, then they put the money in the right place.
It is a Dayton driver but to be fair they totally ripped off the design from AuraSound. If I knew that when I designed them I would have gone with AuraSound on principle, but the small differences make it difficult to change over now.
This is definitely not a transmission line - the port is way to short. For a tuning frequency of 70Hz (like the frequency response suggests), the line would have to be about 120cm long.
It´s a ported enclosure - which isn´t bad...just don´t call it a TL.
I like the inverted dome tweeter. That way you don't have to reverse them after the kids push them in. :-)
I'm stunned at the amount negativity towards a product, which by comparison to far eastern standards is very high quality. The number of comments that say they could build them for $100 is shocking. This of course is a complete impossibility, especially if they are to sell them at a profit and stay in business.
Ok the design of the PCB could be better, with more care taken with the layout. But in low frequency applications, it really makes little difference to the way the circuit functions. These are also pre-production samples, so there's going to be some elements of the design that won't get into the finished production models.
So can we stop with this "I could build them for 100 bucks" bullshit, because you can't period. If you can, then do it and send them to Dave for evaluation.
@@Okurka. The kickstarter states that PCB is outsourced to china.
I don't know a whole lot about the pcb, but the speaker itself is definitely not worth anything above 100. The drivers I'm 99% certain are Dayton Audio which I'm seeing for about 25 euros a piece and the "tweeters" are even less than that.
edit: after watching more of the video I can confirm they're indeed the Dayton Audio ND91 woofers.
What an ignorant dopus. This IS at best $100 of components, few dollars of wood. Kindly fuck off, mate.
This could transition to a premium product with proper QC(the manufacturing tolerances on this thing.. lol), PCB design, and better external design. It looks like a late prototype, or a personal project.. This is not something you sell at +200% premium...
They might have a clever transmission line design, but ultimately the speakers are coupled to a single amplifier (bad, despite the recent trend for "powered" monitors to do this), that's based on an off-the-shelf amplifier IC (still not ideal), use stupid connectors (sorry, but it's true), and individual drivers that are more at home in a TV sound bar than a NFM. And let's not even start on that hazard of a power brick - at least get something vaguely serviceable from LiteON, Delta, or even Mean Well.
They aren't near-field monitors, but a pair of $250USD Wharfedale Diamonds will run circles around these for build quality. And they're made in the far east!
It's some of the claims that annoy me most. 4x50W? Not a chance. Class A/B IC better than Class D? Nope. Alternatives using "inferior particle board"? AFAICT, the "research" suggesting this is 40+ years old - before many modern materials were even widespread - and most speaker manufacturers (even high end) use MDF because it's easier to build precise cabinetry with and does not sacrifice sound quality.
That heat sink on the back should be mounted with the fins running top to bottom. Cooling will be compromised the way they’ve done it.
At 15:20 it’s obvious the rear panel seal is only fitted down the sides, not the top and bottom. That could cause a few problems with the sound. They should be completely airtight except for the transmission line port.
Thanks for that point, Ill see if I can source a heatsink shaped so the fins run vertical, but I do need to work with what's available. Really no problems with heat as they are though.
P.S the green is just a liner on the seal tape as it's sticky and will gunk on the case otherwise. I've not seem it come of like that before, maybe something to do with being in air freight.
Simon A - Bear in mind that your speakers could end up being used in temperatures you may not have anticipated! You ideally need a large safety margin to cover that. Of course, if the user sideways mounts them...! :-).
these are NOT MLTL speakers and the drivers do not appear to be high quality. Notice how none of the driver specs are given here or on the kickstarter. Go to partsexpress.com and you can build your own bookshelf monitors with an active crossover and add a blutooth module for a fraction of the cost. The $100 mark is not far off depending on how good of a crossover you want to build. Also, anyone that knows about resonance understands that for the density to mass ratio and quality control of the product, MDF is a better choice for cabs than plywood unless he is using the finest grade cabinet ply (9 layers or more) and checked for inclusions in the cab. This is a set designed for the recreational person who likes to think they know about something because they screwed nut A into hole B. Just an FYI, I built 3-way MLTLs as my main fronts and the crossovers in them were $300 so please do not mistake a product produced for noobs for quality just because the uninformed think it is.
I've spent my life fixing Pro audio and lighting and for the most part they work. Right angle tracks aren't an issue at those frequencies. As for recording, Doug Ford will tell you the same thing. If a producer can mix a track and make it sound good on crappy speakers, it will sound great on real ones. This does not work the other way around!
Right angle is considered bad practive as acid can pool there and give irregular track width... but it's not an issue with minimum 0.01inch tracks and modern production.
If a person mixes on bad speakers won't there be a possibility of missing something not heard on them that would sound unpleasant on high end ones?
@@trophospherecrappy speakers is how you lay down a track properly. Two enormously popular studio monitors were the YAMAHA NS10 and the Auratone 5c. Both were bloody hideous and you wouldn't wish them on your worst enemy but you mix sound to be played back on crappy systems. No point mixing to sound good on proper set of drivers when people listen to it most on TV. Always lay down tracks for the worst systems, not the best
@@gwyllymsuter4551 so you never engineered for the Berlin Philharmonic?
@@raykent3211 nearly 30 years in this industry. Seen hundreds upon hundreds of studios an oh yeah, my daughter is one of the most famous producers and faces in Asia... Who cares about some orchestra?
IME, the tweeter is what usually fails before the main driver. If the tweeter is not replaceable without destruction of the cabinet, these will become throwaway.
The midwoofer is a reputable unit, but I don't know about the tweeter in the LBM's. They look like they are 1" Tymphany wide-range speakers, kind of like the Harman Odyssey single-suspension mid-tweeter speakers, so they probably aren't "junk" but I haven't heard them sound better than actual edge-driven dome tweeters in my experience. A "transmission line port" was originally done by Irving "Bud" Fried back in the 70's; my parents' old Fried Model Q monitor speakers had them, and they were called a "line tunnel" - effectively they are a lossy port, also called an "aperiodic" port. You actually lose a small amount of deep bass from this approach but you can flatten out the impedance peak of the woofer which makes them a better load for tube amplifiers with their higher output impedance so that the load the amp sees is less reactive. The Scan-Speak Scan-Vent and the Dynaudio Variovent are similar in practice. AudioSmile has been around this block before with some passive monitors using reputable drivers from SEAS in Norway, using passive crossovers.
Yes, they are Tymphany tweeters
They are amazing little 'tweeters' (quotes because they have far wider range and excursion than a typical tweeter), performance well beyond the competition that look similar. But what would you expect from Tympany who oversee Scan-speak, Vifa, Peerless etc..
You could easily call them a damped folded slot port. Transmission Line sounds cool though and it's quite a reasonable description. The primary goal of the damping is to reduce harmonics of the line, rather than flatten impedance at least in my design.
It's stupid of course, but after multiple recodings, improvised test set-up and my poor speakers and ears the Little British Monitors sounded more natural and with flatter response.
That's just your ears getting used to the sound of the monitors.
Dave, I’m a little disappointed that you didn’t fix the symmetry of those tweeter decals while you had the thing taken apart.
Back in the 70's I read an interesting article about doppler distortion in wide-range speakers. In fact you will have a moving sound source when playing, for instance, a 5 kHz tone on a membrane that moves with a lower frequency like 50 Hz.
That tends to be a bit of a headache for coaxial designs, actually, since you're basically putting the tweeter into a vibrating waveguide.
@@PileOfEmptyTapes Also the reflections from the voice coil around the tweeter can cause 'blurring' to transient response. Philip Newell has an interesting chapter on this in his book Recording Studio Design where he measures Tannoys.
Those four pin connectors aren't DIN. They are GX16 aviation connectors.
Aviation or otherwise...
a GX-16 is in fact a DIN Connector
and seriously though, did you think that you were going to teach dave a thing or two with this comment ?
all you've done is shown how silly you can be
i suppose , next, you'll be telling me that an RCA Connector is not RCA , but it's actually Composite hehe
Mate, just keep it simple ok, we all know what we are talking about
To be fair, I bought them under the name 'GX16' ;)
Never heard anybody calling a connector like that DIN in Europe or in USA. DIN connectors in popular parlance are those 13.2mm circular affairs with thinner pins well known from old receivers, cassette decks, and MIDI interface boxes. Not used anymore in Hi-Fi except in Naim Audio gear. DIN is the German Institute for Standardization and I don't know if there is any number ever issued for GX series from them, but those aviation connectors look more like MIL-Spec USA Cannon stuff or alike. Probably very old. In any case I did not try to teach Dave anything, only to remark that those connectors are not called DIN for very many other people, especially when met on audio equipment. Regards.
@@somebodyx it's like people calling one of the power connectors inside a computer "a Molex" and they don't realize that most of them are Molex. They think "a Molex" is a specific plug. They say things like, "plug in the Molex, "referring to a single specific plug. Same with DIN.
@@Audio_Simon And here was me thinking "CB Mic connectors"
Have a good christmas, I personally like the fact you're here to answer questions and have taken stuff on board. Any chance of doing a version without BT? (not just to please Dave, but I've known BT modules cause horrible interference even with a well filtered separate power supply
From the data sheet info that's a terrible (Muriel) choice of a chip. LM1875?
A completely improperly designed audio cabinet, including electronics. Have you noticed the ceramic caps in the signal filtering? Jeeeez...
Even the heatsink is mounted improperly.
I wonder if the piece of wire soldered to the Bluetooth antenna actually reduces range...
What's wrong with ceramic caps? Serious question.
@@davidf2281 Some kinds act like varactors, causing all sorts of undesirable effects to the signal. A test with a spectrum analyzer will show if there really is a problem.
@@NiHaoMike64 I see, thanks. What's the best kind for audio applications? Mica, tantalum?
electrons flying off the corner, thats good stuff!!
I've heard these a few times and it's important to put them into context - for current use and the history behind the design.
They are designed to be flat and accurate, a monitor speaker and therefore somewhat at odds with the norm for small multimedia speakers which are often hyped in the presence region to give added bite and excitement, and boosted in the upper bass for additional thump.
Such anomalies sound impressive on first hearing but can become tiring after extended use, not to mention you are overlaying a set of defined tonal characteristics onto every performance.
The LBM tries to avoid this by remaining clean and neutral.
The ply cabinet is better damped than many other materials, lacking for example the high Q ringing often found in MDF and some plastics which colours mid range frequencies.
I'm sure Simon could make these more cheaply with MDF, and even save some time on machining and finishing - but they'd sound worse.
The hole in the magnet (with the grill) is 1, to prevent pressure and vacuum building up in the dome of the woofer, and 2, for cooling the coil.
Rear heatsink is the wrong orientation.... Noobie mistake right there.
True, I should have noticed that.
Its safer to orient the heatsink like this when they are big enough to work that way, because when the speakers are oriented sideways - no nasty surprises. That heatsink doesn't look very sensitive to orientation anyway, the fins are widely spaced and shallow.
and afaikt the stainless steel back which is s lousy heat conductor is between the IC and the heatsink
@@adymode But they are not designed to work on their side, did you not see the accompanying stands in the first couple of minutes? I've done flowtherm modelling of heatsink orientation and the relationship between fin spacing and height. I doubt given the small amount of total power dissipated.
@Tim Fountain Course I saw the stands they're optional - the speakers cooling should obviously work anyway round.
I can confirm that those are not transmission line ported enclosures, in fact the angle is not smooth and will affect significantly the velocity.
I still think these "chip amp" are all to often overlooked. I've run a DIY LM3886 amp for around 8 yrs on a set of floor standing TL speakers (DIY of course) they rock for the cost and are great little projects. Currently have version 2 in the pipeline.
What really puzzles me is how it can be designed with different high frequency dispersion patterns between the left/right channels. The way the acoustic lens on the tweeter is implemented is really wierd.
I cant believe you really missed the soldermask saying "Flux Capacitor" next to the main Cap. What an epic fail for a "Back to the Future" Fanboy.
not to mention that was probably a one-off board made specifically for him, it was even "produced in Dave-Cad"
You are right Dave. They should put the PCB on the outside and put covers on both speakers to keep the symmetry, inside and out.
Venting the magnet reduces first resonance frequency, not unexpected in a smallish wideband driver (headphone drivers often do the same).
Good attention to detail in construction, parts appear to be nothing earth-shaking but of decent quality. (Yeah, the heatsink could be better, but eh... it'll do.) The speaker link jacks look like those used for radio mics to me... 4 contacts are just what you need for two drivers.
Looks like single supply for the main power amp and split supply for the preamp stage, I wonder how this goes together... center-tapped AC input with 1x bridge rectifier + 2x half-wave?
Pricing is not budget basement, but I mean, these are made in moderate numbers in the UK, not cranked out by the thousands in China, so both economy of scale and labour costs would be working against them.
"The speaker link jacks look like those used for radio mics to me" - XLR
FYI front porting doesn't mean you should stick speakers near walls or corners.
Even without porting, you never do that, as low frequencies are omni directional.
But I am adding a boundary compensation control to the final version.
Besides calling it "rubbish" what is the problem with Blue Tooth? I like it.
So, some thoughts on the review.
Quite right to be dismissive of the cabinet being a real transmission line. A few have already noted this. The original "transmission line" design went back to Bailey, and was a design with essentially no theoretical underpinning. The idea was that the stuffed tapered line would adsorb all the energy off the rear of the driver was a nice idea, but the reality was always going to be something else. There is now quite good understanding of what is really going on, and a few useful design tools available, Martin King's work probably being the definitive, although tools like Hornresp can also model the system and get much the same results. What the enclosure seen is is a tapped line. The port is coming off part way down the line, and you will get a reasonably complex system. There will be a resonant system in the box with the speaker, and other in the box with the electronics, they couple, and there is a lossy resonant port. Add to that a quarter wave resonant system end to end. However, what you can do is tune this mess to produce a range of responses, and with care eventually end up with a flat response. For a small enclosure you might be able to create a more satisfactory (for some definition of satisfactory) result than a simple sealed or ported alignment.
On the subject of full range drivers, an eternal problem with any full range driver is the polar response at high frequencies. As the driver becomes large relative to the wavelength the speaker becomes quite directional. Whilst it is possible to make a flat response on axis, the frequency of the energy in the diffuse field is heavily skewed. Metal cone drivers invariably have a few quite nasty resonances at high frequencies, and part of the art of crossover design is to avoid energising them. All full range drivers, no matter what the technology, have significant resonance issues.
One notes that the bass drivers are about 40 USD each, and the tweeters are probably in the vicinity of 10-20 USD. So the BOM for just the drivers is already 100 USD. Cutting out the enclosure on a home gamer CNC router is not going to be conducive to a cheap result, even if the kit probably goes together with the precision of a Swiss watch.
The driver selected seems pretty nice. It has such nice design features as a shorting ring around the voice coil, and has clearly been carefully optimised. It is great for a small 2 way. One notes there is a subwoofer output. Does using it place a high pass before the bass drivers? Using it with a subwoofer would help greatly with reducing the excursion the drivers need, and would probably drop distortion quite a bit.
With Dave's experience in building stuff for manufacture, some comments on the expenses, and the margins would have been illuminating. Despite the apparently high cost of these speakers, and the moaning, it is not clear how unreasonable the price is. Without serious economies of scale, getting prices down is hard, and in the end, it isn't the ingredients alone that matter. If the final result is good, that is what you pay for. The modern world doesn't seem to value the work in getting it to that point, and expects the IP for free.
Like electrical transmission lines, an acoustic transmission line is supposed to present the driver with a constant, characteristic, impedance. I doubt that is what this one does, and even the best ones, on a proper scale, fail. They aren't really supposed to output anything at the end, and I have never fully understood quarter wave transmission lines because they never add up to Unity. In contrast, a ported cabinet presents anything but a flat impedance to the driver. It's essentially a second, lower, resonance below the driver's main resonance which serves to extend the bass response. (You don't get two peaks as one might imagine, but get a smooth shape if properly designed.) The price you pay for this is a sharper rolloff because you have introduced two new poles; in the mass of the air and the compliance of the air in the box. They are very different things indeed. I hope I have elucidated the difference.
Transmission line converts the sound waves from the back of speaker and changes there Phase so instead of cancelling out they add to what is coming out the front of the speaker.
i use those switches(power) in my detectors, and there is a low profile version that if used in this would mean it didn't need those wire links on the power socket, the power board could be soldered flush.
OMG Please share!
I swear this guy used to do the voice for Dickie Knee
He should be called ‘Helium Dave’.
Dickie Knee was voiced by John Blackman.
EEV - Time to whack out Doug's precision measurement microphones for frequency response.
Run lower frequency sweep with mic pointing at the woofers to find out if electronics make a difference acoustically between left and right
Being transmission line, you’ll have a bit lower bottom end, which is good, given their size. Also, your mid/low driver will have more freedom of motion, if he properly tuned the transmission line.
I really like BC caps(and Vishay branded plastic ones). Electrolytics are most of the time quite a lot cheaper here in EU than comparable series japanese ones.
Nice to see them used here.
My biggest issue with the speakers is that they do not have balanced inputs. Most professional studio monitors have balanced input through XLR connectors
As a line array of small drivers those woofers do work pretty well. You need 30 of them to get a decent bottom end and usually in an infinite baffle configuration. 30 x 1" ports equals a 30" port. Equally those 3½" drivers add up in surface area quickly too. For those drivers to be effective they have to be used in something like a Bose 509 configuration. As for the unpopulated area of the board, I have a hunch that it was for a USB DAC which ironically would have been better than the bluetooth save for the wireless part. You also may want to work the drivers in before you pass judgement. Often the compliance of the driver increases over time. It's like a leather wallet that needs to be worked in a bit before it feels right. I got a set of these and honestly they don't compete with my JBL 4312g but they are rather impressive for the size. Their heaps cheaper too for the level of audio quality possible with these.
OCD overdrive with that tweeter piece.
Dave its the reason only small monitors have all the power amps in one speaker. Most studios NEVER use anything smaller than a 5 " .MONITOR.
I might be missing something here. On the website it states the power output is 4 x 50w, but the power supply is 6A@15v which equates to 90w. So how the hell can you get 200w power out from a 90w power supply ? - do those flux caps double up the power :)
I'm also no expert, but for the money there are better finished speakers out there. He could have added a veneer to the front edge rather then leaving it exposed plywood.
Well, fortunately(?), music is far more dynamic than a constant sinewave, so there's some so-called "crest factor" involved (ie. the power supply won't need to supply 200W all the time). That being said, the power brick sends shivers down my spine. Pretty sure it's light as a feather, and even IF it meets the specs on the label (briefly as it might), it's still no less of a death-trap (like pretty much all those cheap-arse "replacement" laptop power bricks).
@@khronscave Thanks for the explanation. I know what you mean about those power blocks.
@@MalcolmCrabbe Well, there's that, plus the fact that the output power's directly related to the supply voltage. Right on the first page of the chipamp's datasheet, it says "4x 30w / 4ohm @ 14.4v", and that's at 10% THD, so well into clipping territory. Pretty standard rating tactic to inflate the numbers. Figure 9 on page 11 of the TDA7850 datasheet is probably more telling. Assuming no voltage sag, at 15v you'd get a bit under 25w into 4ohms "clean enough" (1% THD).
I wonder what those 120uH inductors near the output are actually doing there, if the crossover is done at the line-level, ahead of the amplifiers. Maybe an RLC notch, to minimize that ~8kHz peak (break-up node) in the "woofer"? See the link for reference: zaphaudio.com/audio-speaker18.html
Not a fan of controls on the back of the monitor. A small box for the amp and the controls would have been better. Would have also resolved the dissymmetry. But good on him anyway.
You're not supposed to change those settings all the time on actual monitors. You set them once and your mixer/audio interface controls the gain for both after they're set.
@@crimsun7186 yeah, but those are just hipsters pc speakers
Why is the heatsink mounted sideways.
The hole in the back is for cooling the voice coil, the grille of for keeping things out of the pole piece.
Hmm, likely Baltic Birch (aka Russian Birch) so there are more lamination and less voids then normal 1/8" laminated plywood. Just me but IMHO it would have been better to edge trim the wood though...
Cheers,
- Eddy
Why the Bluetooth hatred? I'm gonna bust out the oscilloscope and test this!
Disclaimer: I don't necessarily like Bluetooth. It just works faster than most Wi-Fi devices, so it wins by indirect default.
Maybe "balance" the left-right volume by putting a Lithium battery in the second one to provide not just offline power but to reduce the size of the mains brick to deal with only the average power.
The reason why people don't do these kits anymore? Because there is no profit on it unless you ask a ridiculous price like these. I know pretty much which drivers are being used. At my company we sell something similar monitors for just around 80 bucks. And those are sold per around 500 per year.
I am far from impressed for the amount of money
How much markup do you think he's charging per unit?
@@uK8cvPAq . That's difficult to calculate. What i see a lot with amateur kickstarters is that they don't use the right sources. So they pay full price for their parts. So in the end the customer pays for the fact that they don't have their suppliers and calculated labor right. We can get these drivers for less than 10 bucks.
But it's not the whole story. It's about what is available on the market for the same price and what your story is to make up the higher price.
For 300 pounds you can get something that is far more professional and better quality. Like orders of magnitude.
A big manufacturer (selling like hundreds of thousands or millions) would be able to make this for just around 30-40 bucks maybe.
Which speakers does your company sell?
@@Audio_Simon I think you're asking for a brand? We don't sell speakers ourselves for consumer market (only for pro-audio).
But we do deliver the technical side of it (engineering design, hardware and parts). There are a lot of (known) brands that don't do the engineering themselves, the engineering is done by a 3rd party.
In our case we sometimes even do production and assembly for those brands as well.
(yes technically i know I said that we sell them in the first response, but just to make the story a lot less complicated)
Obviously for confidential reasons I can't tell which brands those are.
@@merlingallagher4484 So you can't show your work?
That's not a Transmission line, it's simply a flat reflexport. Still looking like a good pair of speakers though:)
The grill is to allow airflow around the coil, it's for cooling.
I think the holes in the back of the woofer are a cooling port, I think you were mistaken about the sound going through the foam, the sounds goes past the tweeter to the top of the speaker then into the wave guide thing
This terminology gets me every time... I was ready for some nice video monitors when I saw the notification.
using an automotive TDA chip amp is actually smart ive never seen that before. ive only seen them use 2 seperate chips
Swan makes a 3-way speaker kit for $290 on Amazon that you assemble the enclosure and the passive crossover. They are passive so you will need an amp, but reviews say they sound great.
I don't like them... Someone made these and think they are nice and are proud of them - I respect that, but I don't like them at all myself. Cable between the speakers is not my thing either, but dude Dave - these speakers are so small - you will *never* be able to hear any difference between the active and passive box. No way. Unless there is something wrong with it. Potential loss? In this specific case, that's moving into the audiophoolery domain :P. These might be fine as speakers on your computer desk, or even as speakers for the TV, but would I put them in my audio studio? Nope. That's not what these are built for - but they certainly price them and name them to sound like they did.
Nope!
at that price I wouldn't even put them on my desk for my computer. 630$US without the stand. For that price I'm sure you can found a nice used pair of monitors from a well known brand that have some reputation. So for personal use? lets just say you can buy some nice used quality HiFi from the 70's that have that nice warm sound from that aera. Even brand new 630$US gives you a lot of room to built yourself a nice speakers+amplifier couple.
@@blackdevil72 yes. I agree. This would not be my choice at all. I forgot, did Dave say it was a kit? In this case it is totally not worth it. The wood case, you either build one yourself or you pay a factory to churn them out for u. U don't wanna pay for a guy using a toy CNC to manufacture them at home. Unless its special and real fine work - but with all due respect for the creator - this is not worth it by the looks of it.
@@LifeOnHoth Dave said it was a kit and from kickstartter the kit is still 525$US. After having seen one video of some one building them, its not that the kit is hard to assamble but if you do something bad you have a pair of 500$US paper weight. So depending on the quality of the assembling two person won't have the same sound. And I'm not just alking about hability to follow instruction, depending on how wood glue dry you could have small air leak. Plus a little thing I don't like at all and where the guy is a genius he only sent pre-production PCB to group of youtuber and all of them gave him a pass because "oh yeah look like pre-prod, nothing wrong with it, but I can't really judge the quality but over all its good, you could buy them". There is no waranty on the final product, every video I've seen was with a pre-production model. So close to the end of the kick start and he can't show at leat one "finished" productt to the one guy he have sent the assembled kit? Now I'm not sure if I'm clear but that price for so few waranty? I'll pass even if they sound good.
@@blackdevil72 Yeah... that was kinda my idea also... that if this is a kit like you describe it - the price is just all wrong.
This price will get you professional active studio monitors. With warranty, with psu and amp in both cabinets and most important - bigger. Imho - if u go under 5 inches bass element, that's simply not worth the money if u aim at a pro monitor use. I'm sure as speakers for your PC or TV they will be fine, but of course the price is all wrong for that.
I have actually spent some years doing professional wood work many moons ago, and I would also be concerned that if you get those plywood sheets in pieces, about getting it properly joined - though it is not hard, it needs to be done properly.
All in all - basically a worthless product on the account that it totally misses the mark. It's either this or that. :--)
Back in 1973 a coworker and I working at HP in Colorado Springs, CO started an audiophile speaker company, (Green Mountain Audio,) that is still in business 50 years later. So I know a bit about speakers, and can confidently say to your subscribers that so do you. Cheers.
The very best thing for speakers is MDF or HDF not plywood... it’s pretty simple, the heavier and more dense the material the better, the goal is energy absorption... and plate metal on the back is not great... flat amplitude response is great, how about the phase? You can EQ any system ‘flat’ and it will sound horrible... it’s much more about phase and the lobes in the off axis pattern...Their is no real difference in types of tuning, a port is a port, unless it’s horn loaded. Also the foam used is to increase the apparent enclosure volume by keeping the thermal load constant (isothermal), pretty sure that type of foam is not correct. Anyway it’s nice to see young folks experimenting with this stuff, unfortunately MP3 pretty much killed off HiFi simply because it’s an easy to use format, it’s incredibly difficult to find high fidelity signal sources these days.
One word - Tidal
I owned some Ohm Walsh 2's with transmission line drivers and port. Very good sound reproduction and very pleasing to the eye. Don't thin I could fit them anywhere these days.
Look at the trace near the BT module at 18:05!?!? I don’t want to use DaveCad I think
I think they sound a lot alike, but the Focal ones are a bit crisper on the treble... Depends on which you consider more accurate. I assume neither has base.
Transmission line ports aren't always better than typical ports, but in cases with small woofers they often times are. Ideally, the area of a T-line port should be the same as the moving cone area of the woofer, and the length of the port (in combination with the area) determines the lowest tuning of the enclosure. Similar to a clarinet, trombone, or really any other instrument, the length of the port in a T-line enclosure determines its lowest frequency, or in this case, it's cutoff frequency.
At 3:40 you said that Simon mentioned that it's harder to make T-line enclosures for smaller speakers. I really don't understand where he's coming from with that. From my experience, it's much more difficult to do T-line enclosures with larger speakers since they require much more area for the port and end up taking a lot of space. Whether they're large or small the math is all the same, but maybe I'm missing something.
@17:40 "yes its upside down so all the electrons are gonna fall out" no, its right side up, you're down under so its compensated.
Seven hundred u.s. dollars for an amplifier with 10% distortion? Aptx and, aptx hd especially, make a difference in sound quality but any efforts at sound quality are negated by that horrible amp chip. The whole thing seems to be put together from internet research by someone who doesn’t really have an interest in audio quality. In sourcing parts for my own build of a bluetooth speaker into a vintage boombox I’m acquainted with all the components used here and there is a definite mix of good and cheap components. The “tweeter” is most likely another full range speaker. True tweeters are built with sealed backs and wouldn’t need their own enclosure as was done here. The build is incredibly amateur or intentionally cheapened to make the most money. Dave went easy on the guy.
that response graph is pretty good, they actually do 60hz at 0db or 90 whatever way you look at it?
Seriously? It's not often you see a PCB layout that poor. Laptop PSU going through a connector with tiny pins. A ribbon cable carrying audio?
There is no problem with that power connector or ribbon cables for audio. I agree that these speakers are overpriced and there are many things wrong here, but there is absolutely nothing wrong with the things you point out from an engineering point of view.
Indeed, the layout looks quite sad. But the rest of the construction looks nice.
@@chrisdejonge611 The power supply is rated at 6A, those look very thin pins for that and ribbon cable has awful crosstalk characteristics.
@@colinedwards7250 The audio signal is low impedance (line level) at that point so is not really susceptible to interference. I'm sure that connector is just fine for 6A. Again, there are things wrong with the design, but the things you're pointing at are not.
@@colinedwards7250 What i'm more creeped out by is the power supply itself - that thing is a potential death-trap right there. Those [ahem] "replacement" power bricks damn near need a paperweight so the wind doesn't blow'em away, and i wouldn't trust the ratings on the label as far as i could throw'em.
You should give a try to the Neumann near field monitors.. amazing things.
Dave, I wonder why is most vintage stereo audio is better than newer stereo audio? At least, that is what everyone said it at online.
Without fully watching it, the woofer is probably a Dayton audio.
same with the "tweeter"
which is just a cheap extended range driver
Or Aurasound. But this one is indeed badged as a Dayton Audio.
Marco Reps made some a few weeks ago but nice to see the coverage.
So one monitor, with an external speaker. I think I would prefer a small shielded box with front controls and rear I/O with two external speakers. You could also design a matching stand for the amp box.
Who is it aimed at? I am supposing PC speakers for those with space issues?
Hi Dave, here in Britain, our houses are 35% the size of the rest of the world. Thus we are also 35% shorter, and out speakers come in smaller sizes...
/s
All of the connectors on these look unnecessarily spendy! (21:10)
Transmission line speakers should be totally non resonant.. Start out with the square footage of the "pipe" being a fair bit larger than the active area of the speaker.. (fair bit of geometry there..) a 10 inch woofer would start out at about 80-90 square inches..that will taper down to the active area of the woofer at the exit. Built a number of them over the years.. the drivers have to be selected for the job to get good low end response.. I measured my 4' tall designs with a 10 " woofer solidly flat down to below 50 Hz...Fed with a fairly decent little amplifier setup...The transmission line (the "tube" needs to be carefully filled and packed with long fiber wool... hung lin small baskets. You tune the speaker by changing the packing of the wool.. and they are all different.. (Lots of particle board for the walls to keep it non - resonant..)
So what is the problem with right angle traces? I know from my kicad class in college that you're not supposed to use them, but I never remembered to ask why.
Extra inductance and capacitance.
Just get a junk circuit board, hack it to size and install it in the passive speaker to approximate the presence of the active board in the other speaker. :)
Does anyone remember the Minimus7 speakers?
Yes, Dave's Focals with cast enclosure remind me of them more than these though!
They were sweet.
They are on sale now btw, a few years after this video. Price: £529.00. I hope they have been improved a lot.
They are the same speakers..
Been a while since I've seen anyone dabble in transmission line enclosures. I believe they were also called an acoustic labyrinth, requiring multiple baffles combined with a specific weight and volume of damping to slow the rear pressure a full wavelength instead of the half-wave of a tuned port, resulting in a flatter response and without the common 'muddy' sound of the latter, the reason acoustic suspension has superior phase harmonics. Bose has produced a few models featuring these types of enclosures, and I remember someone years ago using plastic conduit to create some Dr. Seuss arrangements for the same effect. Good stuff as usual mate!
~A. Lurker
@@vanjazecevic1159 The first ones I'm familiar with were university prototypes from the 1970s, and the labyrinth was 100% filled, with longhair wool fiber, weighed to produce a more true TL than the half-filled 1/4 wave variant. Approximate dimensions were 5'H x 4'W x 4'D.
interesting speaker set up. soldering inside is hilarious.
what you call a monitor i call a speaker.
300gbp for tda7850 amplifier with normal (not high end) Chinese drivers? supporting the local creators ok, but its not bang for your bucks i think...
IamIUareU It's supposed to be for the other parts and the acoustic design work, not the stuff on the PCB, though at least that circuit hasn't been price optimized to death with bad caps and knock-off chips.
@@johnfrancisdoe1563 he is selling nationalism and patriotism, not quality product (in any way, just as Dave said and confirmed)... otherwise he could pay $1000USD for freelance electronic engineers to design him high quality electronic scheme and design, then he could produce it also with high quality in China and could employ UK Q&A before he shipped the product and would get a really great quality product that would cost way less... Dave did the same (altho he got the design and production for free i think), ask him if his multi meter is high quality and bang for the bucks...
@@Hobypyrocom A lot of EE are terrible at audio circuit design to be honest. This is low frequency stuff, but signal integrity is everything, not getting a pretty layout with neat traces that cause crosstalk and inductance. Many immediately opt to using a ground plane which is also terrible for audio. My PCB may not be the best looking but it works well where it matters.
Regarding making it in China, you've got to realise this is a small production I'm not looking to flood BestBuy.
@@Audio_Simon "A lot of EE" is not equal to all of them... i know some guys that are really cheap and great designers... most of them also dont charge you if you dont like what they designed... the ones i know provide a working prototype included with the design, so you can check first what you will get. if you write a detailed documentation with your requirements, even those who are terrible at audio circuit design will provide you with decent product.
"you've got to realise this is a small production" yes, i am aware of it, but who said that if you produce it in China you have to make millions of pieces? it will be more expensive for small quantity for sure, but again it will beat the price of UK manufactured guaranteed...
think big and aim for the sky, you have a great idea that has huge potential, but at the moment the execution is bad... good luck and best wishes...
@@Audio_Simon Then send those to an EE who is a professional in the audio field, like Doug Ford, who has worked with RODE for a number of years and could test your monitors properly. Anyone can claim EE are terrible at something without subjecting themselves to the same scrutiny. Put your money where your mouth is.
Some of the ways the PCB trace are run is a bit how-you-doin'.
Nice to help and support the real creativity!