This is seriously cool to see. Not only the process but you willing to show the mistakes and the project when it did not go as hoped/planned. Awesome video, love the depth of explanation man.
The smaller chamber should have been on the back side of the sub to create more compression . I believe that would solve the problem. With the bigger chamber on the back side when the frontside builds pressure it will prevent any sound from passing because the pressure is greater.
Yeah, when I look at the construction......I come to the same conclusion (It's worth a try). I wonder what would happen if he put the center baffle back in and put the other driver in facing the same direction.
In my experience yes a smaller chamber for the inner with series tuned however parallel tuned allows you to do the opposite. I have found parallel tuned seems to be more forgiving than series tuned but series tuned tends to play a little deeper as there may be added loading through the main chamber that helps this, anyway that's just my findings.
@@HashDogg06Just for an example, the rear chamber would be like 1 cubic foot tuned to something like 24 hertz with like 8 square inches of port, then the front chamber 1.25 cubic feet tuned to 45 to 50 hertz, with like 18 square inches of port?
Im a 40 yea old man that loved to have a hard hitting system in my 20s, but i didnt know anything about tuning an frequency and such stuff like that back then. Now im older im looking to build a system using more information than i did before. Thanks for great lessons here. I appreciate your hard work!
Wow nowhere else can we see this type of content. Talking about it is one thing but actually experimenting and showing us is another. Thanks for your investment
Sixth order boxes are my favorite by far started doing them by instinct when I was young, when I finally found out what I had been building I saw the series tuned. Never have tried to build one my instinct tells me the likelihood of cancellation is far too high. Now to learn from your lesson. I’m sure you figured it out. You do fine work.
Another awsome video. The testing and the walk-through showing the wrong and the right is what separates you from the ppl just trying to make money. I recommend your chl to everyone even those npt in the bass game. Awsome job cant say enough keep up the great work cant wait to see whats next.
This is a cool experiment. The purpose of a band pass is to filter frequency and amplify it. You are trying to create airflow. You are effectively creating cancelation. The front chamber port seems to have the same area as the rear port causing the compression 0r “back pressure “in the port instead of flow. This is more than likely why the confetti doesn’t move at the correct frequency. To add to that while using the same port area you have added the front port length to the rear port length changing the frequency all together.. I’m glad I watched this experiment, brought back some frustrating memories from the 90’s.
I came late to this, but it's such a FANTASTIC video, I subscribed immediately! You give a great heads-up for everything from "I've failed," (which is pretty rare these days,) to shop safety, theory, and a really good garage engineering empirical test! I'm working through BassBox 6 Pro, and I'm not sure about bandpass in that app- I haven't looked at it because I'm dealing with a real tight space restriction in my Tacoma. Man, this was great! I'll keep my eyes open for more videos from you! WOW!
David McBean's hornresp (free) is your best bet for bandpass. Its real easy to use and very precise as built upon Harry F. Olson's math. Hornresp does all kinds of bandpass. Many years ago I had a 10" Meniscus woofer (not much xmax) in a 6th order bandpass - each chamber was around 1.1 cubic foot - it played 28Hz- 120Hz -3dB - the inner port was 3" ID so probably would go into severe compression at high car sub levels. IT would be cool if you could somehow use pipe for your ducts so you could deal with drivers with BS spec - whatever. BTW - your video skills are great.
I love these small project stuff. I ordered me a few 6.5” subs to play with as well. I see how this doesn’t break the bank to build / play / experiment with and I want to try build a isobaric 6th order for my truck to hide behind the seat. I built a isobaric 6th using two 8” kicker comps back in the late 90’s. I wonder how these beefy 6.5 will do compared to that.
@@BudgetBassHead would be awesome if you built one first so I can take some advice. Preferably something close to 8X8X48” that utilizes 4” PVC tubes as the ports 🤣.
Really cool to see you adjusting box volume, and the confetti trick was awesome! I played around with 6th-order series-tuned boxes 20 or so years ago, and I learned that I am not a patient person... LOL Just some speculation based on what I'm seeing in this video: High ratio chamber designs (4:1, in this case?) tend to lean more towards peaky, SPL-focused characteristics; the polar opposite of the typical desired characteristics for a 6th-order bandpass enclosure, and that peak will more naturally sway towards the higher tune than the lower. If you DO manage to peak the lower tune, it's usually at the expense of SPL output across the board. Driver Fs should typically be a bit below the lower-tuned chamber's Fb. Why? I haven't a clue, but I was able to push drivers harder when I brought tuning up off Fs. Tuning spread should be at most 1.5 octaves apart, but keeping 1 octave apart makes the entire process a LOT nicer, and the results a lot more predictable. That plexi you had on the top was just too thin, and you were losing a lot more output to it than you'd expect. It's kind of behaving like a passive radiator tuned insanely high, and its movement was likely playing a part in some of the stray numbers you were seeing. If you really want to torture yourself, build another 6th-order box, but this time, use a passive radiator on the inner chamber instead of a port. Keep a lot of washers on hand, and use an adjustable port on the outer chamber. You can break physics. There's still a small black hole in the house I lived in at the time. LOL I hope you keep experimenting and trying new things like in this video! It's so awesome to be able to come along with you on the adventure. Subscribed!
I would agree with several points made here. But mainly in regard to the addition of a passive radiator (which can be an excellent way to control air velocity or excitation of standing wave modes. it could reduce max 'Q' considerably (which means peak SPL), but leave you with a buttery smoother response (maybe).
You've created a perfect acoustic-cancelation machine! Well, probably like 70-80% of acoustic energy has been nulled. Won't exactly meet the "BOSE noise canceling" specs, but a pretty good job on your first two iterations. You will have to seriously shorten the ducts that connect between the loading chamber(s) if you're trying for an effective hemholtz resonance to compound active pressure at whichever preferred 'Q'. Try to keep phase offset(s) below 12.5* degrees of initial forward impulse before summation. Also, reversing polarity towards the additive phase path can be helpful as well). >>However, you can also go the opposite direction (design wise), with much longer ducts that have an increased taper & expanding internal volume to produce a phase offset approaching 22.5degrees of initial impulse. But This is stepping into "tapped-horn" mode of operation (well, sort of). All of this is somewhat complex theory with a bit of math plus some trial & error.
With those long vents, Hornresp would be a much better tool to simulate what the results of that build would be like. If you share the dimensions of the build, I'll be able to put together a Hornresp sim that matches it, just to see if the Hornresp sim gives a good match for what you measured.
So while watching it I noticed during the last test in your video you put the craft foam blocks in the larger chamber but took out the foam that was blocking that inner port. So with both ports opened you are back to a 6th order with a smaller inner chamber. Am I mistaken? Maybe you just needed that larger chamber a little smaller. In the beginning I was wondering if you were going to move the sub to that window you knocked out to test how it would react to different sized chambers. That would be a pretty cool box where you can adjust the tuning by moving the sub to different windows/baffles throughout the enclosure
I don't think the first chamber was the size you planned on. If I heard you correct it's supposed to be one cubic foot. Obviously I can't measure it but looks closer to two cubic feet or more.
Yes its huge for this 6.5", especially when CT Sounds recommends .25= 1/4 of a Cu. Ft. Net ported(so this was 5x over the rated Net Cu. Ft.👀), & an even smaller .2 Net Cu. Ft. For the sealed section, like when he blocked it off, to try as a 4th order. It played super low, because by blocking off, waaaay down @ the end of that rear chambers port, that made the sealed/rear chamber even bigger, as it then used the port, behind that block off point as net cu. Ft. For that sealed chamber!
I use 2 of these subs in a series tuned 6th. The rear chamber is 1.36 ft3 tuned to 27hz via a 3" round port 17" long. The front chamber is 2.33 ft3 tuned to 53hz via 40 sq. in of port area. Give it a try. Works quite well in my girlfriend's Chevy Traverse.
15:12 "I'm not going to edit none of this out" BOOM, JUMP CUT! HAHAHA Love the content my dude seriously doing us creative bassheads a favor on the hands on research msot dont have the time to accomplish. I'd have so many more enclosures built I wouldn't want to use between you barevids boom or bust series.
Bro, I appreciate you so much. The way you explain things, the general vibe you have, and your willingness to put in work making videos for us to enjoy and learn from are all great. Thanks so much. I can't wait to build my own 6th order... though in parallel, not series.
The design has the sound waves canceling sound waves. Its like the pressure from the back of the sub was competing with the air on front. I guessed that blocking the part you first used foam at was the problem before it was evan brought up in this video. Your placement of foam in the corner confirms it. Blocking the one corner to keep it from entering the chamber in front of the sub was the fix. You may be better taking the chamber on that side and redirecting it straight or to the right
For a transmission line 90 hz is about 1 meter in length. I think your longer port (looks about 1 meter) is acting like a transmission line intead of helmholtz resonator
And when you blocked off the 4th order port you stopped the out of phase unloading below 30hz tuning frequency allowing the long port to load properly as a helmholtz resonator at 20 hz
Great vid... have you ever made a low frequency truck box with a single 10inch sub and a radiator with a total of 1.5 cubic feet air chamber. Truck boxes usually sit under the back seats.
The 2 levels your registering... is low pressure freq. & high pressure freq. But I'm impressed with CTs mini sub, like my two-12s don't stay steady like that at even 75Hz. 👏 👏 👏 @CTSounds!
Love your videos you're very intellectual explaining and going in depth of what's happening and your goal of what you're building. I kept.... trying to stop the video to get a good look at the design of the ports and before you began playing and testing it, my first thought was total cancelation. 2 ports combined internally doesn't make sense to me. I'm not a genius and I've never built a sixth order or a fourth order. I thought I read built on a 6th order and I thought they had two separate ports that way they could each be tuned individually, but in this enclosure i don't see how that would be possible. 2 Chambers ported to each other with only 1 exit mean the front wave and back wave of the sub are fighting each other, on other words canceling any output! Great video and i hope i made sense. I was so happy to see you stuff the block of foam in the rear side plus block that port and then output!😂😊😊😊. Always great to see what you're working on or experimenting with! Not to mention you're doing this on your own dime to help others learn👍🏽
The small chamber connected to that short internal port is where that nasty 100Hz resonance came from. Stuffing the large chamber caused higher spring damping which reduced this issue, it also likely turned the box into more of a conventional transmission line, very interesting results either way.
My best guess is that you should try to keep your port lengths as short as possible and tune the enclosure predominantly by the chamber volumes. I think your ports are so long they are acting like transmission lines
Wish you had a 12inch meso. I have 2 of them in my jeep. They sound great but I did the build for s.q not spl so the enclosure is smaller and sealed . But I am bored now and want to see how loud it will be with a giant box in the back of the jeep patriot. Lol so I'm willing to fill entire back end of patriot. (Just temporary for fun) I have 37inch width space and 23inch height space available. Is that enough space for 2- 12inch meso subs ported?
I'm glad you are getting a video out of the build. That was a lot of material and effort. The plexiglass is way too thin for a box. It will flex and change the tuning. Maybe put an mdf slab and test it again.
Love the videos .If you got rid of that last long port before the right angle turn I wonder what HZ it would play.On a 4th order on the low hz side .would a divider with a 2 inch hole in it help hold the sub together when playing high HZ .
Perhaps add AMPLE but BREATHABLE insulation material along the ducts and possibly at the point of summation. You'll have to experiment. Either way, that plexiglass is F***ing with your design for sure. By adding that Styrofoam you reduced the bandpass order considerably -2, but gave the rear chamber a point of semi reactive damping. Good stuff. Fun isn't it? Great videos my friend. Keep experimenting! Cheers
I felt bad, you posted the box and it had all that port and looked pretty, then you post it was just a failure lol. Noone can say u didn't try! You're a talented dude!👏👏👏
That's awesome regardless! I really loved that 6th order ya made for the car!I was hoping it was like that, but I can understand it wouldn't been that easy. I can't wait for the next drop!
i sugesst trying out hornresp there you have seperate options for series and parallel tuned 6th order as well as many more options like 3 ways of 8th order bandpass and even the more new paraflex box type
Main exiting port needs more volume bigger shorter and back should be half the volume and length. It's strange how these boxes work because it doesn't calculate normally. I have a (4) 15 in wall in my ford edge with a series 6th similar to your box. I could send plans and spl at frequency if that helps.
I think the issue is which port, inner verses outer was tuned to the lowest frequency. A port usually does not pass frequencies higher than it's tuning frequency very well but it will pass frequencies lower than its tuning frequency. Because of this, the innermost port in any series tuned system should be the lower frequency. But you have a 40 Hz inner port connected into a chamber that's tuned with a 60 Hz port. So almost all of your 40 Hz output is going to be filtered out by the 60 Hz tuning of the outer chamber. I'm somewhat surprised that that outer chamber actually tunes that high because the port is so long, but the results, or lack thereof speak for themselves. Interesting experiment. Another way to think about such a series bandpass box is to model the inner chanber and port and take the FR and QTS snd use that as the driver for designing the outer chamber. this can either model an ABC enclosure or a dual reflex series enclosure depending on whether the driver or just the port goes into the outer chamber. But I never built a box quite like that one. I did build quite a few dual reflex parallel boxes, but you need a proper high pass to protect the driver.
this guy is super cool and as sharp as a tack.would love to hang out and just watch him do his thing.i think it would be like marty mcfly watching the doc on back to the future haha starting calling you doctor bass.
1:1.5 ratio use 7 sq area per cube on rear chamber whatever you use on rear multiply that by 4-5 for the front chamber the rear fires into the front chamber. You also want to stay 1 octave apart so like 30-60 or 25-50 and so forth
Trial and error on 6th order bandpass is a part of it....I remember in the 90s I had a guy bring a show truck in that he had just purchased. It had a 6th order filling the entire bed. Basically it was 4 x15" with each 15 in its own enclosure ported into a common chamber that ported into truck ...it was a beautiful build ....that after it was completed must have sounded terrible so in the "oh shit" moment they cut a giant hole in the 1" plexie glass top in the common part of enclosure to salvage the install. There is nothing worse than building and finishing out an enclosure and having so many hours in it and it sounds like a tomato can. We ripped the box out and salvaged some of the plexie to do a 4th order with 2 of the 15s and a plexie window on back of box...it sounded better and customer was happy to have back half of bed to store all the crap he takes to car shows
That rear side port was starting to look a bit like a TL, may have been able to salvage it by putting some fill in the port to play w/ the tuning a bit.
I believe that you can solve the tune problem with adjusting the lengths of your ports. I would guess to just shorten one or the other little by little find the sweet spot that accentuates the desired frequency….that is one big forth order for a six.5
If I were doing it that way I would have the output of the box coming from the high tuned port... because a high tuned port can pass low frequencies without adding loading, and the lower tuned port will pass through said port easily. Seemed odd trying to series a high frequency port into a low port .. if the rear port were low tuned it would load the woofer and the front high port would pass it's waves virtually unimpeded. One more attempt @ series tuned? Maybe fold the rear port back and forth a bit before bringing it around, and making the front port much shorter and somewhat larger cross section. Good luck!
Awesome video! The two ports are cancelling each other out. 6th order looks so good on paper but if anything is a bit off it fails. Did you measure your TS params or take the manufacturers numbers? Plus I think this is a 7th order because the rear chamber port feeds into the front chamber port. Both sides should have their own port. I think this is a 7th order. ??
I've struggled with understanding series tune. Perhaps what's going on is there might actually be a peak at 10 Hz or wherever when both ports create one really long spiral port with an expansion in the middle, although this wasn't shown in the video. What I know is it isn't as simple as calculating the vented box port lengths for each chamber. For instance, the inner chamber tuned to ~30 Hz. That might be the case in open air, but not only have you the second port and expansion mentioned earlier, but the small second chamber has the port pushing back into the large space behind the driver, so there might be a combined higher resonance there, as both boxes are acting as an air spring on the internal port. The outer port will begin to filter sounds above 50-60 Hz, but perhaps it has its own quarter wave resonance at 90 Hz. Long ports and ports that go round bends have their own resonance issues. Perhaps it would be easier to tune the enclosure using passive radiators that don't have these issues. I've always found parallel bandpass far easier to design as it's just two different ported boxes to the open air that doesn't push back and raise the tuning frequency of each chamber. Lastly is the 8th order, which a popular configuration is the 6th order parallel bandpass, and then both chambers are in series with the third and final chamber ported to the outdoors.
From my knowledge and watching this video I'm seeing a long port on the large chamber that looks to be fairly low tuned then a super long port on the smaller front port indicating an even lower tune. I'm not super familiar with series tuned boxes but most people put the low tuned "smaller side" on the back side of the sub and have it ported into the larger higher tuned side. Typically I've seen 2 to 1 ratios with the small side tuned low and porting into the large higher tuned side. From what I see, your small side that was supposed to be tuned high (with a short port) is actually tuned really low due to the length of the port. Longer ports are lower tuned and shorter ports are tuned higher. .
Okay, so you have my question mark lighting up in my lightbulb, i' have no experience in a 6th order series bandpass so off to the hardware stoore I will heading to after this post. I'm a audio junkie. I need to ask only becuse I do not know , ut I do know that small diffewces within a vent or enclosure can completly alter the sound and performance of a driver. So that being said, did you take into consideration the camber loss being for the sub being under mounted and not top mounted also for the vent gain , and then again for the chamber gain when removing the baffle. I understand that in relation to the total size of the enclosure these are very small volumn amounts but there is always a hard line to everything that once its crossed it can change the total dymic of everything. In the case with the small cabin and vent changes if not accounted for then with the signicant pressure flex in the poly window...I'm just curious if these minor things in combination were enough to skew the anticated tuning.I have no experience yet with this enclosure setup yet... But i like that yoou can me something to do. Also it makes me wonder since you are using the 6.5 meso this enclosure is space demanding so I'm wondering how a transmission line vs 6th order series would compare once desins were polished and worked out? Should we see and compare?
A series 6th order is super complex and the port tunings have a specific correlation. We've spoken on this together before only very lightly. The inner chamber and outer chamber ports effect each other's tuning very heavily. If you lowered the inner chamber port tuning, you also change the exterior chambers port tuning, even though you didn't touch the exterior chamber or its port dimensions. It works vise-versa as well, any change made to one chamber or port also changes the other. I have a formula that I think is close, if you're interested I'll shoot you an email describing what I've found.
The port must be out of phase with the sub, causing it to cancel the sound? Your fail video is more interesting than most peoples main content! Good stuff
Fun video. They can't all be instant success. As you stated,, there is a lot of value in failing. You gained some insights that you might never have made if it succeeded. Just spitballing here, but how did you calculate the port length of the 'internal' port? Did you go directly from the parallel to series? What Im getting at is that the length of the port for the internal port would seem to be the total from the "exit" of the internal box to the "exit" at the front. Does that make sense?
Your short chamber long port is acting like a 1/4 wave transmission line, that is tuned lower than long chamber short port, so the sound being made in your big chamber is being filtered by your 2nd chamber and long port. You really want the volume of your chambers to always be 2 times the volume of any length of port. Essentially you made a frequency filter that is trapping the frequencies you are trying to hear, I would suggest having increasing the little chamber and have it dump into the big chamber, and remember in a series the tuning is going try to find the middle of your two ports, so a 30hz inner with a 100hz outer is going to work more like 50-80 hz, but if your ports are so close in tuning that the outer port drops lower than the tune on the inner chamber you're gonna get frequency cancellation at the desired frequencies.
So the lesson was "never have a negative ratio"? As in, the low-frequency chamber or sealed side (if it was 4th order) should never be bigger than the high-frequency chamber/ported side?
Not necessarily but yes try to avoid that design. The main reason is that the port area of the high tuned side is too small, should have been at least double the inner port area (low tune) or more. By having the port area the same it essentially makes the low end tune way too low as it looks to be 60 plus inches of port plus you run into phase cancellation issues. You see that even when he blocks off the inner port the main port still tunes very low. In my experience a small port ratio will have more peak near the given tuned frequency over a lager port ratio.
The sealed chamber is so large that's why the 4th order peak is so low in freq...I bet if u shrink the size of the chamber your freq response will go up
You might want to download REW speaker testing software ( roomeqwizard ) then do a frequency sweep. I would say you've hit a limitation in Winisp, so try Hornresp (as Brian Steele comments below). Like the confetti though - tufts of wool is another visualisation technique. Did your Tang Band double chamber bass reflex work as predicted? (You called them 6th order bass reflex, but to me that implies -36dB/octave bass rolloff). I was curious if that approach could be used for bandpass - does that make it a series series 6th order? 😵💫
The reason why they sound different after you block the port because front and back of the speaker is like positive and negative. After you block the port, that’s mean only one side of the sub is flowing through the end. Sorry I don’t know how to explain but the perfect example is try use one box that hold 2 sub. One sub face up and the other face down. Play the music and you hear the difference from being both face up and from face up and down. When u face up one and face the other down it cancels each others out. 😂 sorry English is not my first language so I’m trying hard to explain lol
I’m not sure if I’m more impressed by your knowledge, or your ability to teach… Thank You!!!
I appreciate that, thanks!
This is seriously cool to see. Not only the process but you willing to show the mistakes and the project when it did not go as hoped/planned. Awesome video, love the depth of explanation man.
The smaller chamber should have been on the back side of the sub to create more compression . I believe that would solve the problem. With the bigger chamber on the back side when the frontside builds pressure it will prevent any sound from passing because the pressure is greater.
Yeah, when I look at the construction......I come to the same conclusion (It's worth a try). I wonder what would happen if he put the center baffle back in and put the other driver in facing the same direction.
Both sides are the same aside from the small displacement difference from the motor and cone shape
@@fedgeno no bro that's alot of difference in terms of frequency
In my experience yes a smaller chamber for the inner with series tuned however parallel tuned allows you to do the opposite. I have found parallel tuned seems to be more forgiving than series tuned but series tuned tends to play a little deeper as there may be added loading through the main chamber that helps this, anyway that's just my findings.
@@HashDogg06Just for an example, the rear chamber would be like 1 cubic foot tuned to something like 24 hertz with like 8 square inches of port, then the front chamber 1.25 cubic feet tuned to 45 to 50 hertz, with like 18 square inches of port?
Im a 40 yea old man that loved to have a hard hitting system in my 20s, but i didnt know anything about tuning an frequency and such stuff like that back then. Now im older im looking to build a system using more information than i did before. Thanks for great lessons here. I appreciate your hard work!
Thanks for making the video. It’s nice to see when someone shows everything, even if it didn’t come out right.
Glad it was helpful!
@@BudgetBassHead Might be cool to revisit this.
Wow nowhere else can we see this type of content. Talking about it is one thing but actually experimenting and showing us is another. Thanks for your investment
You got creative with this one it's probably your best video the box might not have worked out but it made for a good video to learn from.
Glad you enjoyed it
Sixth order boxes are my favorite by far started doing them by instinct when I was young, when I finally found out what I had been building I saw the series tuned. Never have tried to build one my instinct tells me the likelihood of cancellation is far too high. Now to learn from your lesson. I’m sure you figured it out. You do fine work.
this is actually the best video about enclosures that i've seen so far. Keep up the good work 👍
Thanks, will do!
Another awsome video. The testing and the walk-through showing the wrong and the right is what separates you from the ppl just trying to make money. I recommend your chl to everyone even those npt in the bass game. Awsome job cant say enough keep up the great work cant wait to see whats next.
Thank you for the support! Its much appreciated.
This is a cool experiment. The purpose of a band pass is to filter frequency and amplify it. You are trying to create airflow. You are effectively creating cancelation. The front chamber port seems to have the same area as the rear port causing the compression 0r “back pressure “in the port instead of flow. This is more than likely why the confetti doesn’t move at the correct frequency. To add to that while using the same port area you have added the front port length to the rear port length changing the frequency all together.. I’m glad I watched this experiment, brought back some frustrating memories from the 90’s.
I came late to this, but it's such a FANTASTIC video, I subscribed immediately! You give a great heads-up for everything from "I've failed," (which is pretty rare these days,) to shop safety, theory, and a really good garage engineering empirical test! I'm working through BassBox 6 Pro, and I'm not sure about bandpass in that app- I haven't looked at it because I'm dealing with a real tight space restriction in my Tacoma. Man, this was great! I'll keep my eyes open for more videos from you! WOW!
David McBean's hornresp (free) is your best bet for bandpass. Its real easy to use and very precise as built upon Harry F. Olson's math. Hornresp does all kinds of bandpass. Many years ago I had a 10" Meniscus woofer (not much xmax) in a 6th order bandpass - each chamber was around 1.1 cubic foot - it played 28Hz- 120Hz -3dB - the inner port was 3" ID so probably would go into severe compression at high car sub levels. IT would be cool if you could somehow use pipe for your ducts so you could deal with drivers with BS spec - whatever. BTW - your video skills are great.
second that hornresp is the best programme, but it sure is not easy to use 😅
ill 3rd that lol
Outstanding work, yet again. It's not all glamour, prestige and accolades. Thanks for sharing another experience
My pleasure!
I love these small project stuff. I ordered me a few 6.5” subs to play with as well. I see how this doesn’t break the bank to build / play / experiment with and I want to try build a isobaric 6th order for my truck to hide behind the seat. I built a isobaric 6th using two 8” kicker comps back in the late 90’s. I wonder how these beefy 6.5 will do compared to that.
Go for it!
@@BudgetBassHead would be awesome if you built one first so I can take some advice. Preferably something close to 8X8X48” that utilizes 4” PVC tubes as the ports 🤣.
You don’t know unless you try it’s like trying to understand how that sniper enclosure with the 6.5 sundowns was doing insane numbers.
Really cool to see you adjusting box volume, and the confetti trick was awesome!
I played around with 6th-order series-tuned boxes 20 or so years ago, and I learned that I am not a patient person... LOL
Just some speculation based on what I'm seeing in this video:
High ratio chamber designs (4:1, in this case?) tend to lean more towards peaky, SPL-focused characteristics; the polar opposite of the typical desired characteristics for a 6th-order bandpass enclosure, and that peak will more naturally sway towards the higher tune than the lower. If you DO manage to peak the lower tune, it's usually at the expense of SPL output across the board.
Driver Fs should typically be a bit below the lower-tuned chamber's Fb. Why? I haven't a clue, but I was able to push drivers harder when I brought tuning up off Fs.
Tuning spread should be at most 1.5 octaves apart, but keeping 1 octave apart makes the entire process a LOT nicer, and the results a lot more predictable.
That plexi you had on the top was just too thin, and you were losing a lot more output to it than you'd expect. It's kind of behaving like a passive radiator tuned insanely high, and its movement was likely playing a part in some of the stray numbers you were seeing.
If you really want to torture yourself, build another 6th-order box, but this time, use a passive radiator on the inner chamber instead of a port. Keep a lot of washers on hand, and use an adjustable port on the outer chamber. You can break physics. There's still a small black hole in the house I lived in at the time. LOL
I hope you keep experimenting and trying new things like in this video! It's so awesome to be able to come along with you on the adventure. Subscribed!
Thanks for the tips and Welcome to the channel!
I would agree with several points made here. But mainly in regard to the addition of a passive radiator (which can be an excellent way to control air velocity or excitation of standing wave modes. it could reduce max 'Q' considerably (which means peak SPL), but leave you with a buttery smoother response (maybe).
Are you an Engineer my Brother, I like you took the time to learn from your mistakes and discover a new area in subwoofer design. Bravo for sharing.
Yes I am! Software developer. But this is my true love.
You've created a perfect acoustic-cancelation machine! Well, probably like 70-80% of acoustic energy has been nulled. Won't exactly meet the "BOSE noise canceling" specs, but a pretty good job on your first two iterations.
You will have to seriously shorten the ducts that connect between the loading chamber(s) if you're trying for an effective hemholtz resonance to compound active pressure at whichever preferred 'Q'.
Try to keep phase offset(s) below 12.5* degrees of initial forward impulse before summation. Also, reversing polarity towards the additive phase path can be helpful as well).
>>However, you can also go the opposite direction (design wise), with much longer ducts that have an increased taper & expanding internal volume to produce a phase offset approaching 22.5degrees of initial impulse. But This is stepping into "tapped-horn" mode of operation (well, sort of).
All of this is somewhat complex theory with a bit of math plus some trial & error.
With those long vents, Hornresp would be a much better tool to simulate what the results of that build would be like. If you share the dimensions of the build, I'll be able to put together a Hornresp sim that matches it, just to see if the Hornresp sim gives a good match for what you measured.
Hornresp is such a powerful tool..
It would be better if it had some visual assistance as I for one don't still quite understand how to fold horns.
So while watching it I noticed during the last test in your video you put the craft foam blocks in the larger chamber but took out the foam that was blocking that inner port. So with both ports opened you are back to a 6th order with a smaller inner chamber. Am I mistaken? Maybe you just needed that larger chamber a little smaller. In the beginning I was wondering if you were going to move the sub to that window you knocked out to test how it would react to different sized chambers. That would be a pretty cool box where you can adjust the tuning by moving the sub to different windows/baffles throughout the enclosure
Great tip!
This is what makes basing fun to me is figuring this stuff out
I don't think the first chamber was the size you planned on. If I heard you correct it's supposed to be one cubic foot. Obviously I can't measure it but looks closer to two cubic feet or more.
Yes its huge for this 6.5", especially when CT Sounds recommends .25= 1/4 of a Cu. Ft. Net ported(so this was 5x over the rated Net Cu. Ft.👀), & an even smaller .2 Net Cu. Ft. For the sealed section, like when he blocked it off, to try as a 4th order. It played super low, because by blocking off, waaaay down @ the end of that rear chambers port, that made the sealed/rear chamber even bigger, as it then used the port, behind that block off point as net cu. Ft. For that sealed chamber!
I use 2 of these subs in a series tuned 6th. The rear chamber is 1.36 ft3 tuned to 27hz via a 3" round port 17" long. The front chamber is 2.33 ft3 tuned to 53hz via 40 sq. in of port area. Give it a try. Works quite well in my girlfriend's Chevy Traverse.
Thanks for the tips.
Great experiment and I’ve always found bandpass boxes to be less desirable for the space they take up
Gotta love them 4th orders!! Great video thanks for the time spent.
SCIENCE!!
Great video, love that I stumbled onto this channel.. Totally subscribed! Keep it up!!
Man I wish I paid more attention in wood shop. You are a awesome builder! 👍🏻
Thanks 👍
15:12 "I'm not going to edit none of this out" BOOM, JUMP CUT! HAHAHA
Love the content my dude seriously doing us creative bassheads a favor on the hands on research msot dont have the time to accomplish. I'd have so many more enclosures built I wouldn't want to use between you barevids boom or bust series.
I’m at 10:26 and my first thought is that brace is working like an Aperiodic chamber. Figured I would post before I continue on.
Bro, I appreciate you so much. The way you explain things, the general vibe you have, and your willingness to put in work making videos for us to enjoy and learn from are all great. Thanks so much. I can't wait to build my own 6th order... though in parallel, not series.
I appreciate that
Just curious the wrong parameters entered ? Great Video good luck trying to FIX the issue
The design has the sound waves canceling sound waves. Its like the pressure from the back of the sub was competing with the air on front. I guessed that blocking the part you first used foam at was the problem before it was evan brought up in this video. Your placement of foam in the corner confirms it.
Blocking the one corner to keep it from entering the chamber in front of the sub was the fix. You may be better taking the chamber on that side and redirecting it straight or to the right
For a transmission line 90 hz is about 1 meter in length. I think your longer port (looks about 1 meter) is acting like a transmission line intead of helmholtz resonator
And when you blocked off the 4th order port you stopped the out of phase unloading below 30hz tuning frequency allowing the long port to load properly as a helmholtz resonator at 20 hz
thats awesome!! ive seen a 6th order with 8" push pull with plastic pipes run under back dash into the cab. looked factory. i was like WHAT?? LMFAO!!
What a cool experiment.
Great vid... have you ever made a low frequency truck box with a single 10inch sub and a radiator with a total of 1.5 cubic feet air chamber. Truck boxes usually sit under the back seats.
The 2 levels your registering... is low pressure freq. & high pressure freq. But I'm impressed with CTs mini sub, like my two-12s don't stay steady like that at even 75Hz. 👏 👏 👏 @CTSounds!
Thank you for these videos, I love your thorough explanations
Love this video and seeing your thought process. Have you considered getting a DATs? I think it would help you at a lot.
Dta ?
Love your videos you're very intellectual explaining and going in depth of what's happening and your goal of what you're building. I kept.... trying to stop the video to get a good look at the design of the ports and before you began playing and testing it, my first thought was total cancelation. 2 ports combined internally doesn't make sense to me. I'm not a genius and I've never built a sixth order or a fourth order. I thought I read built on a 6th order and I thought they had two separate ports that way they could each be tuned individually, but in this enclosure i don't see how that would be possible. 2 Chambers ported to each other with only 1 exit mean the front wave and back wave of the sub are fighting each other, on other words canceling any output! Great video and i hope i made sense. I was so happy to see you stuff the block of foam in the rear side plus block that port and then output!😂😊😊😊. Always great to see what you're working on or experimenting with! Not to mention you're doing this on your own dime to help others learn👍🏽
The small chamber connected to that short internal port is where that nasty 100Hz resonance came from.
Stuffing the large chamber caused higher spring damping which reduced this issue, it also likely turned the box into more of a conventional transmission line, very interesting results either way.
My best guess is that you should try to keep your port lengths as short as possible and tune the enclosure predominantly by the chamber volumes. I think your ports are so long they are acting like transmission lines
Wish you had a 12inch meso. I have 2 of them in my jeep. They sound great but I did the build for s.q not spl so the enclosure is smaller and sealed . But I am bored now and want to see how loud it will be with a giant box in the back of the jeep patriot. Lol so I'm willing to fill entire back end of patriot. (Just temporary for fun) I have 37inch width space and 23inch height space available. Is that enough space for 2- 12inch meso subs ported?
I'm glad you are getting a video out of the build. That was a lot of material and effort. The plexiglass is way too thin for a box. It will flex and change the tuning. Maybe put an mdf slab and test it again.
I was told winisd does not work for series 6 orders, works fine for parallel setups.
For series 6th orders I was told to use hornresp
Love the videos .If you got rid of that last long port before the right angle turn I wonder what HZ it would play.On a 4th order on the low hz side .would a divider with a 2 inch hole in it help hold the sub together when playing high HZ .
Perhaps add AMPLE but BREATHABLE insulation material along the ducts and possibly at the point of summation. You'll have to experiment. Either way, that plexiglass is F***ing with your design for sure.
By adding that Styrofoam you reduced the bandpass order considerably -2, but gave the rear chamber a point of semi reactive damping. Good stuff. Fun isn't it?
Great videos my friend. Keep experimenting!
Cheers
Try reaching out to a fellow youtuber who's channel is called "hexibase". He's my recommend for you
I have a question about that box build. What the demostration would would be different if using a more higher powered subwoofer?
This is a flawed design. Regardless of subwoofer.
Thanks for sharing this it was awesome video. Build turns into a Fun experiment
I felt bad, you posted the box and it had all that port and looked pretty, then you post it was just a failure lol. Noone can say u didn't try! You're a talented dude!👏👏👏
I tried.
That's awesome regardless! I really loved that 6th order ya made for the car!I was hoping it was like that, but I can understand it wouldn't been that easy. I can't wait for the next drop!
My next video is a parallel 6th order. Stay tuned.
Awesome to see the table saw next to an air mattress in a bedroom
More videos like this are required, man!
Makes me curious how it would be if you used that original brace as another speaker mount firing opposite direction of the other???
Heck yeah! Very nice and clean Steve!
i sugesst trying out hornresp there you have seperate options for series and parallel tuned 6th order as well as many more options like 3 ways of 8th order bandpass and even the more new paraflex box type
If possible make the rear chamber .5 tuned to 32 and front chamber .8 tuned to 52
i like your channel 😎👍🏻
you make something different and interesting video 🤩🔥💯💯💪🏻💪🏻
Thank you so much 👍
Main exiting port needs more volume bigger shorter and back should be half the volume and length. It's strange how these boxes work because it doesn't calculate normally. I have a (4) 15 in wall in my ford edge with a series 6th similar to your box. I could send plans and spl at frequency if that helps.
How can you determine the cabin gain peak frequency of your vehicle to maximize output around that frequency??
I think the issue is which port, inner verses outer was tuned to the lowest frequency. A port usually does not pass frequencies higher than it's tuning frequency very well but it will pass frequencies lower than its tuning frequency. Because of this, the innermost port in any series tuned system should be the lower frequency. But you have a 40 Hz inner port connected into a chamber that's tuned with a 60 Hz port. So almost all of your 40 Hz output is going to be filtered out by the 60 Hz tuning of the outer chamber. I'm somewhat surprised that that outer chamber actually tunes that high because the port is so long, but the results, or lack thereof speak for themselves. Interesting experiment. Another way to think about such a series bandpass box is to model the inner chanber and port and take the FR and QTS snd use that as the driver for designing the outer chamber. this can either model an ABC enclosure or a dual reflex series enclosure depending on whether the driver or just the port goes into the outer chamber. But I never built a box quite like that one. I did build quite a few dual reflex parallel boxes, but you need a proper high pass to protect the driver.
this guy is super cool and as sharp as a tack.would love to hang out and just watch him do his thing.i think it would be like marty mcfly watching the doc on back to the future haha starting calling you doctor bass.
😄 💯
What do you think about an isobaric 6th order band pass sub enclosure?
1:1.5 ratio use 7 sq area per cube on rear chamber whatever you use on rear multiply that by 4-5 for the front chamber the rear fires into the front chamber. You also want to stay 1 octave apart so like 30-60 or 25-50 and so forth
This☝️
Thanks for the tip!
Trial and error on 6th order bandpass is a part of it....I remember in the 90s I had a guy bring a show truck in that he had just purchased. It had a 6th order filling the entire bed. Basically it was 4 x15" with each 15 in its own enclosure ported into a common chamber that ported into truck ...it was a beautiful build ....that after it was completed must have sounded terrible so in the "oh shit" moment they cut a giant hole in the 1" plexie glass top in the common part of enclosure to salvage the install. There is nothing worse than building and finishing out an enclosure and having so many hours in it and it sounds like a tomato can. We ripped the box out and salvaged some of the plexie to do a 4th order with 2 of the 15s and a plexie window on back of box...it sounded better and customer was happy to have back half of bed to store all the crap he takes to car shows
love the intro and the testig
Should have built it just a touch bigger since it was almost the right size for that plexi sheet. Guess you couldn't know until you tried, though
That rear side port was starting to look a bit like a TL, may have been able to salvage it by putting some fill in the port to play w/ the tuning a bit.
Front port and back port coming together in the same to the exit port will cancel each other out causing a big reduce in sound.
I believe that you can solve the tune problem with adjusting the lengths of your ports. I would guess to just shorten one or the other little by little find the sweet spot that accentuates the desired frequency….that is one big forth order for a six.5
If I were doing it that way I would have the output of the box coming from the high tuned port... because a high tuned port can pass low frequencies without adding loading, and the lower tuned port will pass through said port easily. Seemed odd trying to series a high frequency port into a low port ..
if the rear port were low tuned it would load the woofer and the front high port would pass it's waves virtually unimpeded.
One more attempt @ series tuned?
Maybe fold the rear port back and forth a bit before bringing it around, and making the front port much shorter and somewhat larger cross section.
Good luck!
Awesome video! The two ports are cancelling each other out. 6th order looks so good on paper but if anything is a bit off it fails. Did you measure your TS params or take the manufacturers numbers? Plus I think this is a 7th order because the rear chamber port feeds into the front chamber port. Both sides should have their own port. I think this is a 7th order. ??
muchas gracias por compartir tus experiencias con nosotros ! abrazo desde Argentina !
15:12 " I'm not gon edit none of this out
15:16 : edits it out 😆😆😆
I've struggled with understanding series tune. Perhaps what's going on is there might actually be a peak at 10 Hz or wherever when both ports create one really long spiral port with an expansion in the middle, although this wasn't shown in the video.
What I know is it isn't as simple as calculating the vented box port lengths for each chamber. For instance, the inner chamber tuned to ~30 Hz. That might be the case in open air, but not only have you the second port and expansion mentioned earlier, but the small second chamber has the port pushing back into the large space behind the driver, so there might be a combined higher resonance there, as both boxes are acting as an air spring on the internal port.
The outer port will begin to filter sounds above 50-60 Hz, but perhaps it has its own quarter wave resonance at 90 Hz. Long ports and ports that go round bends have their own resonance issues.
Perhaps it would be easier to tune the enclosure using passive radiators that don't have these issues.
I've always found parallel bandpass far easier to design as it's just two different ported boxes to the open air that doesn't push back and raise the tuning frequency of each chamber.
Lastly is the 8th order, which a popular configuration is the 6th order parallel bandpass, and then both chambers are in series with the third and final chamber ported to the outdoors.
From my knowledge and watching this video I'm seeing a long port on the large chamber that looks to be fairly low tuned then a super long port on the smaller front port indicating an even lower tune. I'm not super familiar with series tuned boxes but most people put the low tuned "smaller side" on the back side of the sub and have it ported into the larger higher tuned side. Typically I've seen 2 to 1 ratios with the small side tuned low and porting into the large higher tuned side.
From what I see, your small side that was supposed to be tuned high (with a short port) is actually tuned really low due to the length of the port. Longer ports are lower tuned and shorter ports are tuned higher. .
Thats plumb bananas
Okay, so you have my question mark lighting up in my lightbulb, i' have no experience in a 6th order series bandpass so off to the hardware stoore I will heading to after this post. I'm a audio junkie. I need to ask only becuse I do not know , ut I do know that small diffewces within a vent or enclosure can completly alter the sound and performance of a driver. So that being said, did you take into consideration the camber loss being for the sub being under mounted and not top mounted also for the vent gain , and then again for the chamber gain when removing the baffle. I understand that in relation to the total size of the enclosure these are very small volumn amounts but there is always a hard line to everything that once its crossed it can change the total dymic of everything. In the case with the small cabin and vent changes if not accounted for then with the signicant pressure flex in the poly window...I'm just curious if these minor things in combination were enough to skew the anticated tuning.I have no experience yet with this enclosure setup yet... But i like that yoou can me something to do. Also it makes me wonder since you are using the 6.5 meso this enclosure is space demanding so I'm wondering how a transmission line vs 6th order series would compare once desins were polished and worked out? Should we see and compare?
A series 6th order is super complex and the port tunings have a specific correlation. We've spoken on this together before only very lightly. The inner chamber and outer chamber ports effect each other's tuning very heavily. If you lowered the inner chamber port tuning, you also change the exterior chambers port tuning, even though you didn't touch the exterior chamber or its port dimensions. It works vise-versa as well, any change made to one chamber or port also changes the other. I have a formula that I think is close, if you're interested I'll shoot you an email describing what I've found.
Sounds good. Appreciate that.
The port must be out of phase with the sub, causing it to cancel the sound? Your fail video is more interesting than most peoples main content! Good stuff
Cheap plexi went welllllllllllll. Not much recoil. Actually considering it for my end all be all😮
Fun video. They can't all be instant success. As you stated,, there is a lot of value in failing. You gained some insights that you might never have made if it succeeded.
Just spitballing here, but how did you calculate the port length of the 'internal' port? Did you go directly from the parallel to series? What Im getting at is that the length of
the port for the internal port would seem to be the total from the "exit" of the internal box to the "exit" at the front. Does that make sense?
Your short chamber long port is acting like a 1/4 wave transmission line, that is tuned lower than long chamber short port, so the sound being made in your big chamber is being filtered by your 2nd chamber and long port. You really want the volume of your chambers to always be 2 times the volume of any length of port. Essentially you made a frequency filter that is trapping the frequencies you are trying to hear, I would suggest having increasing the little chamber and have it dump into the big chamber, and remember in a series the tuning is going try to find the middle of your two ports, so a 30hz inner with a 100hz outer is going to work more like 50-80 hz, but if your ports are so close in tuning that the outer port drops lower than the tune on the inner chamber you're gonna get frequency cancellation at the desired frequencies.
How long is the upper port? It seemed to me to like around 98hz
So the lesson was "never have a negative ratio"? As in, the low-frequency chamber or sealed side (if it was 4th order) should never be bigger than the high-frequency chamber/ported side?
Not necessarily but yes try to avoid that design. The main reason is that the port area of the high tuned side is too small, should have been at least double the inner port area (low tune) or more. By having the port area the same it essentially makes the low end tune way too low as it looks to be 60 plus inches of port plus you run into phase cancellation issues. You see that even when he blocks off the inner port the main port still tunes very low. In my experience a small port ratio will have more peak near the given tuned frequency over a lager port ratio.
The sealed chamber is so large that's why the 4th order peak is so low in freq...I bet if u shrink the size of the chamber your freq response will go up
Lol just seen the end of the vid sorry...lol
Failing is learning bro, my life been full of failures... 3 longterm relationships and 3 baby mama's lol , I'm still at it and learning everyday
Damn, how am i 2 years late to this kind of R&D.
clicked for the meso sub, stayed for the knowledge
You like that sub a lot? The Meso?
I would assume that because the high side is so small it’s acting like a mass loaded t-line.
every time ive seen a series 6th the high tuned side had the bigger chamber and the lower tuned was smaller maybe that was the issue
thank you for your dedication to the bass head fam, your videos are top notch and very entertaining
learning alot , very cool
Glad to hear that!
with the way this is set up could you throw another sub in and run isobarically
Maybe with the window I removed, but not with the current baffle.
You might want to download REW speaker testing software ( roomeqwizard ) then do a frequency sweep. I would say you've hit a limitation in Winisp, so try Hornresp (as Brian Steele comments below). Like the confetti though - tufts of wool is another visualisation technique.
Did your Tang Band double chamber bass reflex work as predicted? (You called them 6th order bass reflex, but to me that implies -36dB/octave bass rolloff). I was curious if that approach could be used for bandpass - does that make it a series series 6th order? 😵💫
Thanks for the suggestions. The Tang Band build was a good one, I've moved on since then though. I am now using Hornresp. Its great.
Maybe the wood mixed with the Plexiglass is causing the tuning frequencies to be different
The plexi definitely has influence in the 80+ frequencies.
The reason why they sound different after you block the port because front and back of the speaker is like positive and negative. After you block the port, that’s mean only one side of the sub is flowing through the end. Sorry I don’t know how to explain but the perfect example is try use one box that hold 2 sub. One sub face up and the other face down. Play the music and you hear the difference from being both face up and from face up and down. When u face up one and face the other down it cancels each others out. 😂 sorry English is not my first language so I’m trying hard to explain lol
plays in the 20s I call that a win.
What if you flip the speaker