What Does a Tweeter Horn Do? And Diffraction Myth Busting
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- Опубликовано: 28 июн 2022
- The horn flares I made serve to push the tweeter behind the front baffle to improve time alignment, and increase the efficiency of the tweeter by about 5db in the 1500Hz to 10kHz range.
The tradeoff is a dip in the response higher up at 17KHz, but that's an inherent problem with horn loading. That dip won't be audible for the majority of listeners, though, and certainly not me.
As I said in the video the response is technically better with the tweeter flush mounted (as opposed to horn loaded), but then that puts the tweeter farther out of line with the other drivers. What's more of a problem? Flattest tweeter response or time alignment? It's my opinion that both are fairly minor in the grand scheme of things and one can be sacrificed to improve the other without cause for concern.
There is another factor: the solid walnut horn looks cool. It's a nice contrast with the cherry that the speaker is made from.
As for diffraction, that's often much ado about nothing.
If you have a microscope, you see germs, even the ones that are benign.
If you have measurement gear, you see wiggles in the response, even the ones that are benign.
We simply don't hear minor fluctuations in the response, especially higher up in the frequency range.
Is flatter better? Yes, but that's like asking if a day with 5% cloud cover is better than a day with 7% cloud cover. There's a measurable difference, but certainly nothing you'd notice unless you tried to measure it.
I see guys presenting measurement data where they are picking out "issues" in the response that in reality amounts to nothing audible. Turning you HEAD slightly while listening will disrupt the response more. Sitting slightly lower, closer, farther, or over to one side or the other will all impact the frequency response that meets your ears.
And I won't even go there on what the response looks like in an untreated room...
That's why I included the recorded music - to give you a real example of what the tweeter sounds like after each change. You can judge for yourself whether you hear a difference, and whether the difference means better or worse.
Yes, making great sounding speakers involves doing things right, but mainly it's doing all of the big things right. The big things take it 99% of the way and deserve 99% of your attention - driver selection, box design (or baffle design), driver placement / spacing, crossover design. Only after you've maximized what you can with these core components should you shift your focus to that last 1%.
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The horn flares I made serve to push the tweeter behind the front baffle to improve time alignment, and increase the efficiency of the tweeter by about 5db in the 1500Hz to 10kHz range.
The tradeoff is a dip in the response higher up at 17KHz, but that's an inherent problem with horn loading. That dip won't be audible for the majority of listeners, though, and certainly not me.
As I said in the video the response is technically better with the tweeter flush mounted (as opposed to horn loaded), but then that puts the tweeter farther out of line with the other drivers. What's more of a problem? Flattest tweeter response or time alignment? It's my opinion that both are fairly minor in the grand scheme of things and one can be sacrificed to improve the other without cause for concern.
There is another factor: the solid walnut horn looks cool. It's a nice contrast with the cherry that the speaker is made from.
As for diffraction, that's often much ado about nothing.
If you have a microscope, you see germs, even the ones that are benign.
If you have measurement gear, you see wiggles in the response, even the ones that are benign.
We simply don't hear minor fluctuations in the response, especially higher up in the frequency range.
Is flatter better? Yes, but that's like asking if a day with 5% cloud cover is better than a day with 7% cloud cover. There's a measurable difference, but certainly nothing you'd notice unless you tried to measure it.
I see guys presenting measurement data where they are picking out "issues" in the response that in reality amounts to nothing audible. Turning you HEAD slightly while listening will disrupt the response more. Sitting slightly lower, closer, farther, or over to one side or the other will all impact the frequency response that meets your ears.
And I won't even go there on what the response looks like in an untreated room...
That's why I included the recorded music - to give you a real example of what the tweeter sounds like after each change. You can judge for yourself whether you hear a difference, and whether the difference means better or worse.
Yes, making great sounding speakers involves doing things right, but mainly it's doing all of the big things right. The big things take it 99% of the way and deserve 99% of your attention - driver selection, box design (or baffle design), driver placement / spacing, crossover design. Only after you've maximized what you can with these core components should you shift your focus to that last 1%.
@@MrChompenstein Even a bad sounding speaker can have a flat response! It astounds me, how speaker builders and audiophiles alike, can't get past that FACT! Curved edges and horns or no curved edges or horns … and I wish the audiophile community would place more emphasis on what does matter, and that's the relationship between speakers and rooms, as Earl Geddes correctly stated ruclips.net/video/L4Bm123cKAM/видео.html
There is NO, ONE solution, that covers the millions of different listening environments/rooms that the speaker has to fit into .... none!
If you're from a generation used to mono then sure diffraction doesn't matter much. In fact you end up getting a larger sound from the secondary diffractions which are essentially 2 tweeters and 6 diffractive radiation sources.
Where it matters is in modern times when people use two speakers and stereo imaging matters. This style of speaker testing is why people think stereo isn't 3D sound. When you have a truly transparent speaker where the diffraction is controlled, diffraction is often even used constructively to enlarge the sound of the tweeter. Andrew Jones creates rings around his Uni fi drivers and many kef drivers also use diffraction outside the surround and sometimes use the diffraction of the rim itself to create the impression that a tweeter placed at the throat of a woofer is larger than the woofer itself.
This is what gives their speakers such commonly reviewed holographic imaging where you can hear not only stereo separation 360 but sound above and below you.
The LS3 5as were the first studio monitors meant to be standardized monitors licensed by the BBC. They needed to add a foam rectangle around the tweeter to get the imaging to produce a coherent sound stage. The LS50 had a receded surround and uses the surround itself as the end of the flare as a waveguide. The convex design is meant to eliminate baffle diffraction but the Z flex has striations that diffract sound from the tweeter.
This is why the their waveguide uses a compression style series of fins called the tangerine waveguide. You can hear it's effects here.
ruclips.net/video/j6lG_EOiv8Y/видео.html
Designed beyond the LS50 use diffraction constructively. When the diffraction is in a circle and on phase with the woofer you get even dispersion between the tweeter and the woofer and no shot gun effect.
The whole purpose of the tangerine waveguide was to tap into the energy at the rim of the tweeter dome which makes diffraction even more prominent and possible to harness.
Wow. So well said (and demonstrated). Thank you for this important contribution to the discussion.
The dip is not inherent to waveguides per se. Proper math and modeling will avoid it to a degree that it is practically inexistent.
@@marinusr9339 Right. So you say it isn't inherent, yet you say that it can be avoided so it's practically non-existent.
Which is it?
If it's something that can, at best, be avoided, then it's obviously an inherent problem.
That's like saying that lack of light due to it being night isn't an inherent problem, because you can sleep through it.
I know this is an old video but perhaps you'll get to reading this somehow. I have been an avid speaker builder and designer for a couple of years now and I've always been bummed out by the drive for perfection and competition within the speaker building community. I also like a certain degree of professionalism in order to get a ''well designed'' speaker but I always felt judged by the true audiophiles. They kept getting hung up on those 'smaller' things like diffraction, acoustic lobing, dampening etc etc.... I like your way of thinking. Testing some of the widespread ideas about said things, measuring them but also adding some real world common sense about whether or not something is measurable and more importantly audible.
It's just very refreshing to me to see a builder/designer who knows/sees the imperfections but likes the outcome anyway and just takes it all with a grain of salt.
Really love that you're doing the speaker series. I enjoy it and it can be such a contentious topic because every audiophile on the planet has their 'opinions', but they often state them as fact. Love your presentation and your work!
Except those of us who are professional audio engineers.
Its literally like watching an artist work sir. Always have truly enjoyed your videos from an amateurs point of view, with many many years of continued practice I can hopefully be half a craftsmen you are someday!
Nice channel and video! Really nice craftsmanship! Anytime I see painter's tape to fill in gaps, I know I'm gonna enjoy the build! 😂
FWIW, the real issue with diffraction isn't so much the on-axis dip. It's the response off-axis relative to the on-axis response; the reflections sent out into the room have a different response profile. Ideally the off-axis and on-axis are similar in response (just, narrowing in directivity like a good waveguide does). While you did perform an off-axis measurement set, you gated the response (as would be typical for quasi-anechoic). But, at the same time, it also doesn't allow you to get a typical in-room/in-seat response that would show the real issue of diffraction. What would be ideal would be to get the ±30° radiation and compare that to the on-axis. You should see the this region is stronger in response than 0° and this delta is what causes typical diffraction effects to result in issues in-room at the seated position (often shoutiness or sibilance depending on the baffle width/distance of tweeter). Second, the dip ~16kHz looks to be cancellation between the dome and throat termination but I doubt anyone would notice it and the tradeoff for what you gained is well worth it IMHO. And the purpose of the waveguide being to control the radiation and in doing so, what you have here is a waveguide profile that is narrow than the flat baffle (a flat baffle is a waveguide, too, just ±90°). Not sure if you knew this already but you mentioned some doubt as to what was going on the HF so I thought I'd try to help there.
The one thing I really like about your waveguide is that it doesn't result in a peaky response. Rather, it acts more like a shelf filter; raising the response without creating a high-Q resonance that needs a more complex crossover network. Kudos!
At any rate, killer stuff, and I'll be watching more when I can.
Hi Erin and thanks for the comment.
When I do a test like this my goal is to try to get people to learn to put things in perspective. Way too many people today fixate on what are minor issues and lose sight of how important they are in the overall.
Diffraction is a measurable and fixable "problem", but that doesn't make it a significant one. Plenty of highly regarded speakers did nothing at all to mitigate the effects of diffraction. In fact it's like they went out of their way to cause more diffraction with surface mounted drivers and a rim around the baffle.
This isn't me saying that diffraction should be ignored, just that it's in that last 1% of gains you'll get in a speaker design. And that the gains in that last 1% are going to be mostly of the peace of mind type - the "I did it so it's not a problem anymore" category where you can imagine you hear a difference.
I think some people can hear that last 1% and some people can't. (I think I could when I was younger, at least, and so I design speakers to minimize diffraction.) What matters more is that you guys are having a thoughtful conversation about a fascinating and controversial issue. Cheers and thanks!
Yeah its interesting as I did a bunch of sphericals etc. re diffraction. I agree with many of the other comments but using a small flat plane and not having the return angle will not provide adequate comparison. Ultimately...can we hear it is so true. With sphericals, especially single driver, the absence of phase smear is huge in my experience.
Great work though...really enjoy your vids
Horn shape is *extremely* important, even on a shallow horn like yours.
You will find there is a significant difference in the response, especially off axis, between your current horn and a conical horn.
Your horn will have some amount of beaming (as shown in your measurements) because of the shape, you will find that making a conical horn will give you constant directivity which many people find very desirable.
Horns are a very complex subject. I agree that getting close to a particular shape is probably good enough in most cases, but the difference between particular shapes as really significant. Also, unless your tweeter is meant to be horn loaded, you will get much better results designing it to be a wave guide.
"Horn shape is extremely important, even on a shallow horn like yours."
There is NO, ONE solution, that covers the millions of different listening environments/rooms that the speaker has to fit into .... none! To state otherwise, is hugely misleading ... at best!
@@juststuff5216 Didn't state there was a best horn shape. I merely stated it was extremely important, and gave an example.
@@joshua43214totally with you. John seems to always make speakers that HE likes, aesthetically and sound wise.
The biggest change in sound from his horn design will likely be the off-axis response and the impacts that makes. To design a horn without regard for its impact on sound is like popping a large inductor in a crossover because you think they look cool. If you like the sound as a result, that’s great. But it’s a very trial and error approach and just objectively makes little sense to do if sound is a primary concern.
I've followed your channel consistently for the last several years because it is one of the best maker series on RUclips. I like the approach you are taking as an enthusiast and not a physicist. You have obviously read a lot about speaker design and acoustics. It is sensible that you are using as much science as is available to you, but also using your ears, common sense, and taking it slow. The best thing is your are having fun, and I believe you will be well satisfied with your efforts at the end.
I agree. Having fun with this hobby is great.
Amazing job, love the work you do and how you approach it
Thank you for producing this video, it serves as a great reminder for people to not lose focus on why they're building speakers.
So many are building speakers for measurements these days
These may be some of the best videos on RUclips.
What a coïncidence, I did the same type of measurements (flush vs non-flush) yesterday on a tweeter too. The diffraction on-axis on the non-flush mounted tweeter largely disappeared15 degrees off-axis and up. The problem though with the diffraction is that it makes it a bit more difficult to get the cross-over right, especially getting the transition between mid/tweeter smooth under different angles.
Good call on the oil base stain. Back when I was doing hardwood flooring, we always used an oil based stain before the water based finish. (There are water based staines that can be used, but they also "pop" the grain...so you have to sand everything again before coating with finish.)
Wow, finally someone who actually agrees with me. I have designed many audio systems and I love what you say in your description about "turning your head slightly, sitting higher/lower, closer, farther, etc... it will all impact the sound that meets your ears". Granted, there are many differences in sound we can hear, but much more we can't. LOL.
Wow! That was sooo mush better and informative than I expected. Thank you so much!
Hi John , congrats very fine work!!!! About the edge treatment, something from Siegfried Linkwitz /linkwitz labs :The benefits of edge rounding come into play only when the radius is greater than 1/8th wavelength. Thus a typical 1/2 inch radius begins to diffuse the diffracted wave at frequencies above 3.4 kHz, but will decrease in relevance at higher frequencies, when the driver illuminates less of the edge due to its increasing directivity. With most speaker cabinets the radius or chamfer is acoustically too small and is primarily cosmetic. Regards from Germany - Stefan
Off Axis and diaphragm are the two words I came in on you searching for almost at the end of the video, well done on your research
Love these speaker serieus. Really learning some thing here about different shape and what effect on the sound 'colour'..
I listened to the 5 different pieces that you have near the end several times. The more changes you make, the less defined the violin is to my ears. It sounds less crisp, and with the first (surface mount) I could hear the string vibration on the neck, but the more alterations made I hear less and less of that.
I went back and listened to the full clips of each, and those nuances are lessened with each subsequent change.
I'm pretty certain that my hearing is more specific/precise at higher frequencies than most people that I know. I can hear things that others cannot.
I've been in 2 situations (different times, different locations) where an electronic device that is used to scare animals away from bushes have been used, and they are excruciatingly painful if I'm within 20ft of that device. Everyone else that was around me could not hear the device at all.
So, surface mounting is the method I'll be going with, for the sake of accuracy/detail.
hope you are enjoying the project :)
when i built my own design i put in all the features i could fit into my design, sure was fun making it and its heavy for its size and inert with all kinds of rounded angles edges.
Pro audio tech with 45 years experience here. What you made is not a horn, it's a waveguide. A horn is an acoustic transformer that matches the mechanical impedance of the diaphragm to the acoustic impedance of the air in front of it. This raises its efficiency, damps the diaphragm movement, and reduces distortion. A horn always has two things that a waveguide usually does not: (1) a throat in front of the diaphragm that acts as a compression zone for the wavefront coming from the diaphragm, hence the term, "compression driver," and (2) a mathematically derived, constant "flare rate" that does the matching of impedances and also sets the low frequency limit for the driver/horn combination. Yes, a horn also controls the directivity of the driver, but it can make the dispersion wider than a bare driver, not just narrower. JBL and Electro-Voice have both made "diffraction horns" that actually widened the dispersion of the driver beyond what it would have been by itself. Good horns also have a phase plug that time-aligns the output of all areas of the diaphragm as the sound enters the throat of the horn. The lack of a phase plug is what causes the dip in the HF that you mistakenly refer to as "an inherent problem with horn loading."
A waveguide does not increase efficiency, it increases sensitivity, which is not the same thing. It increases sensitivity by forcing the output of the driver to be confined to a smaller area, increasing SPL in that area at the expense of other areas. A horn actually increases efficiency; that is, it increases the ratio of acoustic power output to electrical power input. Increased efficiency usually leads to increased sensitivity, but the reverse is not always true.
Waveguides like you're making are perfectly legitimate. Nothing wrong with them at all. Just don't confuse them with horns. And most of what you write in your description is very wise, especially about diffraction effects and the importance of getting the big things right before worrying about the little things. Well said. And, your woodworking is awesome.
I now await the naysayers who will insist that I'm wrong, despite having little to no experience in the matter.
It's a horn, Scott. If there was no efficiency boost and everything was just a result of focused directivity, the off-axis response would have dropped and certainly wouldn't have clipped.
Waveguides are just horns by another name.
Thank you!
Rounded corners of the cabinet flatten out the amplitude under the side angles. So you see more differences when you do 20° or 30° measurements.
The larger the horn, the lower in frequency that first dip will be, and there will also be new dips forming. It's called comb filtering. It's to do with the original output and reflected signal constructively and destructively interfering with one another. Where it adds or subtracts depends on the phase difference at each frequency given the same group delay.
You can compensate for this somewhat with the geometry so the horn acts more as an impedance-matching horn rather than something that reflects the sound, but of course mathematics is needed to calculate the horn dimensions. That's not something I know much about. Something to do with parabolas, I think.
I find no words to explain my support to your conclusins. You provide measurement ground for what was my ear experience some 30 years ago when I build speaker set for audio presentation. (And after years of continuation consider valid).
My sets was in those times unparralell and I used twweters with fronts originally supported wih those small hornes, similar to yours - It worked by ear exceptionaly in synergy with my unusual crossovers.
Those big sets were purchased from me by one my amazed colege and he proudly presented it to others.
Then happend what you said - people like flat. Colege "discovered' from ads that domes without horn are flatter, and they cost more (better) and not being experienced, not looking my advice he removed my "horn" tweeters and replaced with pure domes. Of course he had been sure it was better because wider sounding but.... only for some time.
He couldn'd get back beacuse the was so stuipid to hand over "horns" to speaker shop where experienced seller was happy for it. They were not produced by company just because customers liked flat. So those my sets ended as spares and colege became customer of JBL and B&W. Without much happiness due to that lack in few kHz Actually he damged my constructiom even more to prove he made good decisions
I confirm with my experinence all your conclusions - there is no much to admire in band above 12 kHz but noise, THD distortions and some residuum harmonics which with amplification some may find attractive becaiuse it doesn't exist in ordinary natural istening. The same as in lower than 30 Hz.
Horn flares shape is very important, rounding edges for diffraction needs a bigger radius and is for interaction with the room, not direct response which you are measuring.
great video with objective tests AND a musical test. thanks!
Youre awesome dude! Good work! Great to watch and learn. Subscribed 😊
The rounding over makes the response more noticeably better off-axis. That’s why it’s not very visible on your on-axis measurement.
Absolutely love the myth busting!
A lot of people worry about sh_t they can't actually hear.
I don't think there was much myth busting here. There where differences in every recording.
Nice work! A couple of things, yes a small round over is just pretty much decorative, it has to be a large round over like a 2" radius to be of real use. Also yes lot's of horns will have that throaty sound it takes a lot of work to get the to sounds right IMHO, now if you have space to make a wave guide, you still get a efficiency benefit, though not as much, but it will also lessen the throaty sound and not have the drop off, plus the design is easier to get right as it's just a constant radius.... Oh also with horns you run into the possible problem of the tweeter diaphragm deformation from the additional pressure needed which is why it is preferred to have a metal of ceramic diaphragm, with a waveguide as there's not as much pressure you can use a soft dome.
Anyway really like your series on speakers and room treatment!
I bit strange that air which is so prone to compress may pose danger to tear. deform tweeter. Have you done this confirmed? There is danger in electrostats when wind blows in diaphragm but dome?
@@Mikexception not personally but it was from one of the bigger companies that has done r&d into it... I would guess that it's not as pronounced with smaller horns.
@@attainableaudio4533 Pls. do not take it personally cause it is very common in talks but it anoys me so much that I "have" to make my point.🤔
People get some information by reading or listenig from someone they perosnally do not know and don't know his credibility, Then they back and present it in a way as this was discovered by them. This way they add their personal credibility (which is normal to receive from side in seldom contact) to opinion which they do not even have any right to support. Some not true opinions get by any mean not deserved value as "shared by many" and . 'having strong foundation" without anybody effort of checking them..
I accept passing on other person opinion but on warning condition that we did not make prof of it, it is not our conclusion, and we could not be assured in any way about that . Which actualy is positive sign of self awarness. it does not apply to knowledge which is common life experience like mine with air mass and compression and would be strange to underline that personally I do not know
In opposite cases all we face ubeatable flooding of ideas which is actualy main problem in audio They live their own "communication" life only on base that they are repeated from hand to hand -power of popularity rises a false "star idea" 😡
@@Mikexception no don't take anything personal, with people I don't know.😜. I don't care for the sound of horns so in the 30 plus years of this loudspeaker making hobby I never bothered to research it, just passing on what I read from one of the designers from jbl or Klipsch or one of those big companies that has the money and people to do the proper r&d. It was years ago though and you know how memories can be, that's why I said possibly, I thought ai said that it was from some designer I read but looking I guess I didn't. as far as the round over and the waveguide... yes, those I did my own research/testing/designing/measuring after reading about them. haha
Good video John, it's a good deal see what we hear. It is possible that you try with other horns, changing its generating curve, you know...spherical, exponential and so on. Greetings.
Love the cheap performance increase. I also built my horns by eye and they work great. I think its easier to avoid a hole longer up if the waveguide is very close to the dome.(over the surround).
I built a couple tweeter horn flares on the cnc lathe that look very similar to yours. What I found out was, the longer (deeper?) the flare, the lower the frequency at which the tweeter would go down to.
Hi, and than you for an inspiring channel! Concerning the so-called myth: Why I'm concerned with diffraction is not because of the frequency response changing, but alterations in the time domain. Sharper corners will (!) cause louder delayed "echoes" of the initial waveform than rounded ones (preferably with a large radius), and even though the echoes are minute and hard to measure, our ears pick those up like clues to where the sound is coming from. If one of your goals is to make the speaker disappear, then diffraction is a major enemy. It's about imaging, it's not an audiofoolish thing to care about, and you don't need Golden Ears to hear the difference. This is also not possible to demo through a mono recording, via RUclips to a pair of random speakers in the other end. Just my two cents. Have a nice day and keep posting!
Ha you read my mind and beat me to it. I think you are right on track and my experiments with diffraction treatments on my Polk 7B speakers where I strictly use my ears because that's all the equipment I have, have confirmed this.
I don't think it's "audiophool, but the effect it has is much, much less that people make it out to be. Everyone I've ever heard talking about is operating on the assumption that it's a problem, and that assumption is coloring their expectations.
Have you taken the time to do a one-to-one comparison between an identical set of speakers, one pair without diffraction mitigation and the other with? Not two different pairs of speakers - one with rounded corners and the other with square - but the same speakers, two sets exactly the same other than the rounding.
And even if you do, those expectations based on the assumptions about diffraction will affect the results.
@@IBuildIt I can remove the diffraction treatments (tweeter and midwoof wool pads and anti-diffraction roundover frame) from my Polk 7B speakers and all the magic just comes out. The shimmer and decay time and airiness is gone/diminished and the speakers are less transparent. Maybe it is possible that we don't have a tool to measure this except our ears or maybe mic location is crucial and stereo imaging is crucial?
We do have a tool to measure it - our ears - but they are connected to a brain that's subject to influence from other sources. Like our eyes, what wee see, and our expectations. If you are expecting an improvement because you've been told over and over again that an improvement will happen, then that will effect what you hear.
The only valid way is to do it blind. Have someone else make the changes and make it so that you can't see what you are listening to.
@@IBuildIt I'm a bit out of my league here, knowledge-wise, but would something like a spectral decay plot show it up? Something that would show how the decay time of a tone or combination of tones is affected? I can go back and forth without being blinded and can hear more low level details like being able to decipher the words of background vocals that are at a lower level. I feel that is definitive for me.
Great vid! I am working on my own speaker design- full range line source, built out of cherry. Trying to perfect my wood working skills and procedures before I ruin my material. lol Im doing box joints, thought the router would work good but I didnt like the way it cut cherry so now going for the dado blade approach. How are you attaching the baffle to the cabinet, sealing the drivers to the baffle?
One possible adventage of the horn loading is to actually match the wave front of the tweeter to the midrange making them sum coherently in phase at all angles. This improves the integration off axis. You can shape the response to be flat way off axis and even increase the dispersion in the top end compared to a flat baffle. How the horn is shaped and how it attaches to the radiating surface of the membrane is important. To avoid destructive reflections.
Thanks for this, it saved me a ton of time.
I have just subscribed to your amazing channel! Its a joy to watch your videos. What would be the best speaker stereo you consider the best and on what technology was based(open baffle, sealed box, ported box, passive radiators, transmission line...etc)?
A couple thoughts: the biggest effect of edge diffractions will be off axis, so your measurement position won’t pick it up much. But most importantly, violin is a *terrible* perhaps one of the worst instruments for evaluating speakers because of its very tonal nature. In order to hear the whole speaker, you need a very spectrally dense source. Like for examples pink noise. If you don’t believe in using pink noise, then choose music that is very dense. Just think about it: when a violin note is playing, you hear just one spot along your spectrum, plus a few harmonics. You need something that plays sound at all frequencies at once if you’re to hear the speaker for what it is.
Violin is equivalent to judging a painting by illuminating it with only red light.
But… amazing work and craftsmanship! Super cool!
You are wrong on that first point. Diffraction shows up most in the on axis measurement and mostly disappears in the off axis. But that's neither here nor there if the effect isn't actually audible.
As for the violin, if the effect was as audible as it's made out to be, you should be able to hear it no matter what's playing.
interesting about the diffraction - I should do some measurements on that to really know for sure. Unless you have some handy. But about the audibility: we can definitely agree that you can’t judge a speaker by playing a single 1khz tone through it, right? So, clearly, what’s playing does matter. Similarly, you couldn’t possibly judge bass response of a speaker by playing a violin through it, just like you can’t judge highest octave of a tweeter by playing a kick drum. If the test signal doesn’t excite the speaker throughout its entire band (that you’re trying to test anyway), you can’t make valid judgments on it. That’s why the spectral density of source signal really matters.
@@big_whopper No, you're right. He makes sweeping points, glossing over diffraction characteristics that have be proved to make an audible difference on and off axis. He also ignores diffraction's role in shaping the sound beam width of a tweeter across the freq spectrum, and ignores the integration with the mid/woof's own beaming width. And he did not measure the impact of the mods on the horizontal & vertical axis.
In other words, to make an analogy, he is using a voltmeter to measure a complex signal and uses that to support making the point that complex signals are no more interesting than steady ones. Instead of using an oscilloscope and then explaining all the various content. Pretty misinformed and misleading.
Great woodworking skills. Poor audio knowledge and demonstration. Hopefully he'll keep learning in this domain and provide more accurate content to his audience...
Wait. You have a speaker channel, too? Amazing.
The higher volume in the lower range is also due to the fact that the dispersion in the lower range of the tweeter will be bundled (because the horn acts like a wave guide). Which is (imo) more interesting, because this will cancel wall reflections, resulting in more direct sound, enhancing the sound stage and therefore the quality.
I agree that a flat response is less relevant. It can color the sound, but that is also a matter of taste.
Ah , you may have given the answer im looking for.
I replaced a couple of tweeters with on paper very similar. In practise the new sound bit quiet.
Difference new have a flat metal plate . The old a bit of a plastic horn .
I love these kinds of projects. doing something for the sake of doing it.
Interesting - I like the first audio example best.
Great approach. Been doing similar for years on my builds. The other thing with the waveguide which is a big plus is you gain controlled directivity improving room integration and polar matching with mid. Roundovers must be MUCH bigger radius to work as in 6 inches plus. Then you’ll see a more significant improvement.
Horn gain as you discovered can alter linearity despite upping efficiency so usually I’d expect more complexity in the crossover. No biggy.. I thought the horn music sample sounded way more coloured unfortunately with flush mounted the best. Flush mounting the waveguide and more crossover work needed to deal with that. You’re right to avoid dsp correction where possible. Never sounds as good as a well designed all analogue passive to me unless just to lop off bass peaks in room. Often destroys smoothness of polar response which designers sometimes overlook and that matters.
Interesting experiment! I've build a few speakers myself, from scratch and must admit i think I hear a difference between on baffle mount and flush with a big round over. Doesn't mean it was better either way.... I do try to get a flat ish response with a 2 db drop from the lowest to high frequency. In my opinion this way the speaker gives the best representation of how the recording "should" sound. Assuming there is no eq used offcourse.
That cone shape is really important! Na just kidding, i wouldn’t know, but someone is going to say it 😂
the angle on the throat is too steep. I'm with you 100% in regards to the importance of the 10khz plus range. awesome vid! 👌
Couple thoughts:
- Measuring in such a small and highly reflective room adds tons of reflections and makes such measurements less real.
- The horn changes not only the eq curve, but how the sound will radiated in different angles, so one point measurement provides few answers.
- The horn also can change the phase, also in relation to the direction, so....
And I am sure you can hear around 10kHz still, where the horn still affected the sound. Nothing comes for free.
So educational thank you so much.
You rock dude. Keep going.
I really enjoy your approach of using experiment to verify the theory. Demonstrates expertise in acoustic testing and development. I learn a lot from this channel...
I would think that you could stick both of them back on the porch for a couple of weeks while they off-gas the oil based poly. The poly will protect them and they can still get some more tanning in. They are looking great.
Hello John, how about a piece of carpet around the tweeter to reduce first reflections from surface?
The first and the second examples are a bit different in long notes. The second sounds a bit more open at these exact fragments, but this is a 10% difference )
I think you will need a super-tweeter 10-30kHz if you'd like to use that horn
I agree with you, the worrying about the rounded corners and minimize diffraction differences that you won't hear but people seem to be worried about is a bit too over the top, I'll always say flat sounds boring usually, and if it sounds right (regardless of measurements) and seems to work in your room then that's a win in my book, measurements don't always mean better, depends on the person and room, if it makes sense and sounds right leave it alone, don't get too caught up in perfect measurements.
There are 2 main reasons to control diffraction:
(1) comb filtering showing up at various frequencies / off axis angles due to edges & boundaries close to the tweeter
(2) reflections from room boundaries (which can add or substract from the on axis listening)
He pretty much ignored (2), and did not demonstrate (1) as the measurements and the audio samples were only on axis (except for 1 plot at 30o) instead of a full horizontal / vertical scan.
So, it is not even about what measures well / not, here. It is about not even measuring what should be measured when talking about diffraction.
From his meaurements, leaping into _'does not matter, people should not worry about this stuff'_ is misleading and misinformed.
Flat sounds always better but that is only the case if you take all the measurements in account, not like this video where he only measures one axis. The sound of a speaker is formed by direct and indirect sound and thus what may look flat on one axis may be not flat on another. The complete speaker should be analyzed instead of doing just one measurement only than can you make such statements
i could definitely hear the difference when the horn was added. sounded like it was playing through a toilet paper roll, definite midrange honkiness. i agree the best mounting is probably flush for that tweeter. It makes sense as those drivers are not designed to be horn loaded in the first place, but to be flush mounted or panel mounted.
A horn is one of the means for matching the impedance of the diaphragm and the air. Therefore, since the impedance of the horn is matched, a sound pressure signal proportional to the electrical signal is obtained, resulting in a clean sound. (However, whether or not you think the sound is good depends on the listener...)
By the way, when the impedance is matched and the horn operation is successful, the impedance of the speaker becomes flat. Even if you install a horn (or something like that), if the impedance is not matched, the sound quality itself will not change, just the sound will be louder.
I like the second one the best. The horn sounds like it's in a tunnel. Still impressive how much more decibels you can get out of them.
It's like comparing a ceiling light and a flashlight.
It would be interesting if you compared a phase correct 3 way with a out of phase 3 way. The push pull from one speaker to another should be interesting
And here I am, just having upgraded to titanium diaphragms on my Klipsch KG5.5s, wondering if I can actually hear the difference or if I just blew a bunch of money to feel like I did something.
Just another thought. What about the acoustical impedance change as the sound waves from the tweeter follow the 3/4 roundover and then encounter the sharp corner at the back edge of the baffle? If that were extended back to form a box shape would that effect be minimized or could that be done to see if there is any difference? I also wonder if it would've been more noticeable diff if you had not offset the tweeter.
As an aside, there is a guy on DIYaudio who did a 2" radius diffraction frame on the sides only (not the top) and got a much smoother response and better off axis dispersion in the midrange frequencies but it didn't seem to affect the frequencies over 4kHz or so. Just FYI.
"Diffraction Mitigation with PVC"
Pretty good pdf article on Diffraction. Search on "Acoustic Diffraction: Does It Matter?" He says D'Appolito states 3/4" radius is not much good below 18kHz !! I had read elsewhere online that wavelength can be 8 times the radius size or less. Ya read something different everywhere.
Im a woodworker myself and oil based definitely brings out the depth and beauty of the grain much better than water based. Also is much more durable in my experience as a contractor.
Saw the title and subscribed
A Scientific American article from the 50s 60 or 70s (wish I knew precisely) installed a transducer on period violin(s?) to determine their resonant frequency response. The result was not flat at all, actually it had quite a lot of variability and it was periodic. I don't recall if the pattern was periodic with the 12-tone octaves, but it may well have been. In any event, I now strive to identify the optimal "notches" for a given speaker and make liberal use of narrow band carefully tuned spikes in the frequency response with eq. Easy to discredit, but if there is a formant you find aesthetic, why not put it in your transducer?
Thanks for this video because I have been thinking about the effect that adding a waveguide to my Peerless KO10DT tweeters might have on frequency response and baffle diffraction but also the ability to time align somewhat by recessing the tweeter in the baffle a bit more. For edge roundovers isn't the largest wavelength it is effective (as a rule of thumb) for about 8 times the radius? So then a 3/4" roundover would only really be good down to 2250Hz (OK for tweeter I guess)? I have experimented with 1-3/4" roundovers (965 Hz) on my Polk 7B speakers and like what I hear but perhaps it is also helping with the critical midrange since crossover (2 way) is at 3kHz.
PS: I believe we probably have to go to distortion measurements to get a better idea of what our ears are hearing clarity wise. Doesn't diffraction cause time delays of different amounts, like little speakers located at the edge of the baffle and aren't there phase shifts as well? Just my 2c.
I looked at the distortion of all of the samples. The first three (surface, flush and rounded corners) are identical.
Would be interesting do the same test and compare with a inversed dome tweeter? So.. yes, 2 different tweeters will sound different but speakers manufacturers usually talk about dome vs inversed dome, vs horn, vs etc.
I know nothing about speakers, but I think one more setup to try is the tweeter mounted behind the wood without the horn shape. Does the shape matter? How much difference does the shape of the horn make to just straight/parallel wood?
Yes it's paramount. There is a piece of software called ATH4 and AKABAK that is made to design and simulate just that.
Generally for Hifi you don't design horns and this thing is not a horn, it's a waveguide. The difference is that horn matches impedance of a compression driver to air. It increases efficiency. A waveguide just guides waves. It focuses them the same way that a reflector inside a flashlight focuses light. A bare driver is a lighbulb hanging from a ceiling. The same driver in a waveguide is a flashlight. IT is more sensitive (louder) because you measure gain on axis, however it does not radiate more sound into the room. A horn however can surpass that by means of increased efficiency. There are many kinds of horns and waveguides, but if you want to make one yourself, you need to know just a few things:
The small opening is called a throat.
The diameter of the throat determines the highest frequency that will be affected by the gain. The smaller the throat, the higher the cutoff freq. In reality it is determined by the size of the dome + half of the suspension. The throat is the most important part in your design, because whatever happens here will be amplified.
The big opening is called the mouth.
The mouth area defines the lowest frequency affected by the gain. The bigger the mouth area, the lower the cutoff freq. It also affects general directivity of the speaker even at the low frequencies. The bigger the mouth diameter, the more directional it is. This is used to match the directivity between the drivers.
The distance from the throat and the mouth is the depth of the horn.
The deeper the horn, the higher the gain. In basic hifi/monitor speaker building the depth is defined by the so called z offset of the tweeter and the midrange. Generally speaking midrange drivers are more recessed then tweeter domes, so their waves are lagging behind the tweeter. This creates phase issues in crossovers. It can be fixed by using asymetric slopes in XO, but you can also just recess the tweeter into the baffle. The exact depth of the recess will be between 15 and 25mm and you measure it with an impulse test.
The transition between the throat and the mouth needs to be maximally smooth for the best result. It's different in public address, but for Hifi we use smooth waveguides. This transition will determine spatial distribution of the sound, it's directivity.
Now, big waveguides cause problems, because they lengthen the distance between drivers. So for maximum mouth area but reasonable distance, people often use squashed or rectangular profiles such as the Seos horns.
Designing waveguides is an iterative process. Some designs take more than 15 iterations of just the transition before you squeeze the best directivity out of it. ATH4 makes it quite speedy though. Some people don't do iterations because they mostly affect the last octave, which isn't particularly important.
Ode to Joy - my neighbors love it!
Magnificent artistry in your total approach to this project. After 33 years in Music Education, my hearing drops off rapidly after 12kHz but I can still hear pretty well below 12kHz although my wife says I never hear what she says. A story for a different forum. 😂 on the violin clips there were subtle differences with each and even though I’m insensitive to frequencies above 12kHz there’s still plenty of “meat left on the bone” to be able to make assessments about the audio quality.
Looking forward to the next episode.
Bravo John!! 👍🏻👍🏻👍🏻
Baffle diffraction isn't really something measurable that way, it's ulterior sound sources that'd sum up. It's like the equivalent of tweeter passive radiators. You can actually use this to your advantage. KEF uses diffraction outside of their tweeter around the outside the mid woofer to make it sound as if the tweeter is the size of the woofer or more specifically to merge the tweeter and the woofer.
Have you thought about trying an elongated elliptical horn? Basically do similar to what you have but like a heavy weight sat on it and squished it.
I made one from plastic: ruclips.net/video/zVT4PrXJlbU/видео.html
How does the tool called at 5.06?
Thanks
Very informative, thank you. Can you test speaker cables at some time? BTW: What sort of tweeter is that?
it looks right.... man, you had me laughing..... it looks good.
This series is fascinating. I have a dumb question i always wondered about but never heard anyone mention even as a variable... in regards to time alignment, would it be possible, if the tweeter sat lets say 1 inch more forward of the bass driver on a baffle, just to run an inch longer cable from the crossover to the tweeter to compensate? Would the effect be the same as proper physical time alignment or no?
Speed of sound is much slower ( many order of magnitude) than the speed of electricity you would need hundreds kilometer of wire to achieve the same delay
@@thecarl168 thanks for the answer, had no idea electricity flowed at such speed
@@albertkelly7129 It's pretty close to the speed of light (derated depending on the dielectric used). So, indeed, pretty fast 😉
I like rounded corners. But I've never heard any difference.
I suppose maybe if the enclosure was spherical... but a half inch round over, eh.
I love horns for PA/stage use but I miss the crispiness for hifi use & typically I'm padding down tweeters & sometimes mids because they're already more efficient than the woofers, more would be a waste. Then again, my listening space is way too bright.
a dome tweeter has basically two big problems, it is compressing the music heavily, and it has a very high level of distortion. The gain of +6db with your horn means that you only need 1/4 of the power you needed before. This is a significant reduction in compression and distortion.
This tweeter (Scanspeak) has very low distortion, actually. But yes, driving up the efficiency also means that already low distortion will be even lower for the same output volume.
This is just plain untrue good dome tweeters (scan speak, seas etc) have very low distortion. The only thing they have is relatively high second order distortion in comparison to most woofers but that is no issue as research has found that our hearing mask most of the second and even third harmonic distortion due to masking. Compression is also bullshit most dome tweeters starting to have serious compression when you push 100+ db not the kind of volume most people are playing music in domestic settings. It is obviously not the right driver for pa kinda applications
Love the videos. Just a quick one on this one... a violin's frequency range is between 200Hz to 3,500Hz. I'm guessing from the piece you played the highest frequency played was about 700Hz. Need a piece that can test the high frequencies.
There was content in that music right up to 12khz.
hifi is a collective of each small, iterative improvement that, hopefully, adds up to a distinguished result.
Thank you for the detailed tests! I have to say, to me the off-axis horn recording sounds worst of all. It may be my imagination that the rounded corners sounds best.
The biggest problem of sudiio judging is that on spot unnatural sounding is perceived as amazing While perfect it is sound that is perceived as "normal", notthing special; So in judging on spot - speacially with one instrument and narrow band it is hard to say what is good or bad .
I can see what a horn supposedly does, but if you put the speaker 5" closer wouldnt that be the same thing ??
Horn shape is simply far more important you know.....
Thank you for myth busting this. Is it an open baffle design?
What if you made the horn shallower?
I think it would be fascinating to try this with cone tweeters.
Conical tweeters are basicaly working like horns but without intentional gain Due to shape they tend to divide source with frequency and it is their graat advantage in compare to domes which do not. That advenatage alow widranges to sound good.
Wait why is the speaker so off center?
Tweeter horn.....I thought that was something rel;ated to Twitter 🤪
The way horns make speakers more efficient is by condensing (altering) the sound wave thus distoring it. Think megaphone. Horns were developed due to amplifiers being weak back in the day. We have powerful amps now so don't need archaic technology (like vinyl and tubes). But they look cool.
You got the second part right, horns were developed to work with low powered amps. But your conception of how they work is incorrect. They do not cause distortion, in fact they can actually lower the distortion for the same output level from a driver that doesn't have a horn.
comparison 4:52 and 5:56 I believe i hear a small difference, a small amount of more brightness but i might be wrong.
please fllow it up with phases plug and ribbon driver in horn
Funny thing about acoustics is, it all depends on earwax density, position within the ear, the length of the ear canal and its shape. What sounds good for one person can sound like absolute garbage to someone else. Testing electronically requires an anechoic chamber to cancel room acoustics before analysis.
subscribed
For me, only the off axis horn sounded different.
That tweeter horn shape looks like that of a tractrix flare.
The results with the horn should have been enough to make you abandon it. As an older guy too I understand the higher frequency hearing loss . But you could build in a rising response at higher frequencies to compensate for your hearing. So therefore the dip in response up at the higher frequencies from your tweeter horn cannot be justified in any way… especially for your hearing. It merely looks good.
Horn is good enough if you look at the response. The guy who mentions a conic should come and visit me. If you want greater output higher up you need to decrease the inside diameter and get it nearer to the dome O.D. stand it off with an O=ring of both appropriate thickness and diameter. The only caveat to using a tweeter lower in frequency is if the distortion is acceptable. Erin's comment on diffraction is the best one. Otherwise from a guy who has been designing horns 30 years and and loudspeakers for 35 years you walked the talk well enough for me.
No one that talks about diffraction bothers to mention that there has never been a scientific study that proves its audibility. Why is that if it's such a big and easy to hear effect?
But in the same breath, they'll dismiss (rightfully) the idea that cables make a difference for that exact reason: a complete lack of proof of the audibility.
Now there's a difference between doing what you can to minimize diffraction, and ranking it as something that MUST be done or your speakers will be subpar.
Guys with little practical experience tend to focus on issues that may not be important. They haven't developed the real world ability to rank the significance of all the factors that go into building a good pair of speakers.
@@IBuildIt Yep the interesting thing to me is that while it is many times easy to measure, depending where the differences are it is not so easy to measure using music as a source. Usually the differences need to be db or greater. And further. It is best that the listener doesn't see the difference or the magnitude of the changes. This biases the listener. Where did you find a solo violin version of Beethoven's Ode to Joy?
All the music I use now comes from the RUclips audio library.
It used to be that the dogmatists in the audio world were almost completely on the mystical side, the subjective side, where the rationale was that we hear stuff that can't be measured. Like the high end power cable, interconnects, magic crystals and other nonsense.
But now there seems to be a growing amount of dogmatic thinking on the "science" side, the objective side. Science in quotes because these people are the type that think science is something that can be settled. They think of it as a noun, when it's actually a verb.
They follow the teachings of their tribal leaders with a religious fervor, so we have today these two extremes that dominate the discussion.
@@IBuildIt There is enough science to clearly tell us what is audible and where it is audible. All you have to do is search psychoacoustics and you learn that our ability to hear some things is a lot less acute than we may believe. Other regions it is amazingly acute. Don't get to hung up on what you talking about. Diffraction effects can be a red herring. And in some circumstances can actually be a cause of irritation. But the idea that because you can see a tiny difference in a graph it is definitely audible No. No I have had that proven to myself. And I have passed that on to others that tell me they can hear 20K and it is night and day. So I blindfolded them and did partly random changes in the response of the music that they were used to. And low and behold, unaided by the suggestion we have by means of our sight, that is looking at a graph, the ability to detect those upper reaches of sound are not so certain. To many people listen with their eyes.
i can imagine you would look fabulous in a feather boa and heels, dude.
My comment to your do you hear it or not is this:. Now that I am older my hearing does not hear as high. Does that mean that those younger people can't hear those high frequencies because I can't? Just because you can't hear the difference doesn't mean that others can't. That said, very interesting video. With a properly designed horn you should get 9 db of boost at the bottom end cut off of the horn.
I'm not sure how you came to that understanding. I didn't say because I can't hear it, no one can.
Edge diffraction is a measurable effect, but our ears (and brain) don't work like a measurement mic. So you can't look at what a mic "hears" and say our ears will detect the same things in the same way.
If they did, there would already be a few studies proving the audibility of diffraction. Instead, we don't even have one scientific study proving diffraction is detectable while listening to music.
And yet people talk like it's a settled issued, like of course it can be heard. The same people who probably scoff at someone who claims to hear a major improvement by lifting his speaker cables off the floor. Both are operating on half understood ideas and blind faith with no actual proof to back up their conclusions.
Need to actually A-B the dome tweeter in a "horn" vs. mounted flush with a small baffle (or sphere). And with music not just a meter. The horn will not sound as open.
What looks right.. Hahahaha! I love it!