BIG Bass in a Small Room - Making Infinite Baffle Subwoofers
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- เผยแพร่เมื่อ 1 พ.ย. 2021
- After the very encouraging results I got from the open baffle subs experiment, I decided I'd go all in and put them directly in the wall. This is known as infinite baffle, where you are just getting output from the front of the drivers without any interaction with the back wave of the speakers.
My listening room's front wall has a utility room behind it, so it's nearly perfect for this setup. All I had to do was cut out the drywall directly behind the woofers to open them into the space. The utility room acts like an infinitely large box and completely eliminates cancellation from the back wave of the woofers.
I did have limitations on where in the wall I could put them, and this close to the floor isn't ideal. But the results are outstanding - flat bass extension down below 20Hz in the room and the woofers are neatly out of the way.
These are four 12" woofers with each pair wired in parallel (for a 4 ohm load) and driven by a 100 watts per channel Yamaha receiver that can deliver nearly 200 watts per channel into 4 ohms.
The "Mad Max" recording at the end was done on a Zoom H1 using the built-in mics from the listening position. The Zoom H1 has two mics built in for a "stereo" recording. Not the greatest mics or recorder, but close enough to give you an idea of how the room sounds.
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After the very encouraging results I got from the open baffle subs experiment, I decided I'd go all in and put them directly in the wall. This is known as infinite baffle, where you are just getting output from the front of the drivers without any interaction with the back wave of the speakers.
My listening room's front wall has a utility room behind it, so it's nearly perfect for this setup. All I had to do was cut out the drywall directly behind the woofers to open them into the space. The utility room acts like an infinitely large box and completely eliminates cancellation from the back wave of the woofers.
I did have limitations on where in the wall I could put them, and this close to the floor isn't ideal. But the results are outstanding - flat bass extension down below 20Hz in the room and the woofers are neatly out of the way.
These are four 12" woofers with each pair wired in parallel (for a 4 ohm load) and driven by a 100 watts per channel Yamaha receiver that can deliver nearly 200 watts per channel into 4 ohms.
The "Mad Max" recording at the end was done on a Zoom H1 using the built-in mics from the listening position. The Zoom H1 has two mics built in for a "stereo" recording. Not the greatest mics or recorder, but close enough to give you an idea of how the room sounds.
How about adding an “Aperiodic Membrane” behind the Sub drivers? Easy enough to do in your situation with the utility room behind. It would be another great video you could run before and after measurements! If not that’s cool too. I really enjoy your videos! Keep up the good work! 🤘🏻😎🤘🏻
@@doctersound9630 Thats interesting. If its infinite baffle whats the point in absorbing the backwave though>?
An "aperiodic membrane" is one part of a type of subwoofer enclosure. It is an air-permeable sheet which has frequency dependent acoustical resistance properties. The original design goes back to Naim, for use
in home systems, but has been applied by several individuals and
companies in car audio.The completed system will be aperiodic, which means it will prove to be over-damped with a Q well below 0.7. In contrast, the most commonly used sealed enclosures have Qtc's in the range of 0.8 to 1.1 which are considered, by definition, to be underdamped. When improperly used, a high-Q system may have poor transient response, nasty peaks in frequency response, and high rates of roll-off. Aperiodic systems will feature excellent Aperiodic systems are characterized by better transient response, flatter frequency response and somewhat extended low frequency response.
Cheers! 😎🥃 - Hope this helps!
I would pay to hear this set up
Doesn’t some bass bounce back in from the other room?
Woodworking audiophile, what a combination! Your studio looks amazing.
Finally someone doing it right. This is more like how I'd build out my room if I owned my own house with a basement. Good job
A new acolyte in the Cult of the Infinitely Baffled. Very nice.
That's a lot of bass.
The recording at the end did sound like being in a movie theatre, even with it coming through youtube and my open-back headphones.
The bass being inside the wall looks really cool, too! Nice job on the panels, one would not guess you had altered them like that.
Your videos answer my questions better than digging through tons of forum posts on open baffle/infinite baffle
I'm glad I found this channel. Nice work.
Circle cutter router jig using one threaded rod!! The idea is so simple and yet effective, cant believe I've never noticed it before in your videos! I'm gonna borrow your jig idea, thanks for the video! 👍👍
I have been running two manifolds of six, 12" subs in my attic for the past few years and absolutely love the quality and quantity of the bass.
I also have an infinite baffle subwoofer setup in my theater. They are amazing. Great video. Thanks for sharing.
Man - look at that flat response!!! 10-20Hz must feel amazing!
Your are a true craftsman and you got a lot better at speaker building
What a great video and a nice finish to a huge project.
Subs are settled, now to finish the rear wall diffusers, door and then I can get started on the new main speakers.
The room response is crazy good
This is beyond insanity, I love it. Consider the V8 thoroughly honored by your deeds.
I gave you a thumbs up just because the title said infinite baffle
Welcome to the world of IB bass!
If you find that the direct wall mounting vibrates your front wall too much, make 2 more panels and build manifolds with the drivers opposing each other, with the opening where the drivers are now.
Block off 1 of the woofer holes in each panel for possible future expansion.
That setup will reduce/ eliminate any sympethetic vibrations that the drivers induce in to your wall
Wow this is so cool. well done.
I'm learning something new on every video!
I am too :)
Sounds great on my headphones lol.
Awesome setup man.
The wall looks cool with the subs in it. All modular/ woody/ componenty...
"Infinite" baffle designs are awesome. I love that you've effectively turned the room behind into a giant subwoofer cabinet. I wonder if there's any promise in adding a floor to ceiling, wall to wall enclosure behind the baffles in an installation without a room behind to use as an enclosure. I don't know, but I would imagine that there would be significant comb filtering from the backside of a shallow enclosure no matter how big the other two dimensions get. Just spitballing. Thanks as usual.
That response below 20 hz is ridiculous!!
It's all about the bass 🎯
Hello John,
First of all, thanks for the effort to bring us your experience with sonic acoustics tests in your listening room.
I have some questions:
- Which is the dimension of your utility room behind the front wall?
- Is the utility room (as an infinitely box) affecting only the subwoofers or the rest of your front wall? You treated your bass traps based on drywall structure behind...
- Did you make some frequency response measurements in the utility room before installing the open subwoofers?
Thank you very much.
Hi All - I have 4 x 15" original Adire Tempest subs in Manifolds build into the floor in my dedicated room. The floor cavity is the box.
2 Drivers in each Manifold, facing each each other to cancel mechanical vibration, with the top open into a hole in the floor. A manifold behind each main speaker, in the front corner.
Technically they are over-damped, QTS is 0.4, but practically.....awesome. Similar to John they extend well below 20hz. Rolloff stuff, F3 and all that....is irrelevant, it all happens so low it doesn't matter. As they are flat (room excluded) through the relevant frequencies, group delay is very low.
After EQ (Multiple Subwoofer Optimiser to EQ them together, then the Anthem ARC over the top), the in room response is very flat - but you will always be at the mercy of the room, and you can't move them around for a better response.
Excursion has never been a problem. At normal listening levels they barely move. There is no air spring to overcome, and loads of cone area. Therefore distortion is low.
At insane movie levels they move a bit....but the floor/room is shaking like crazy..and at ludicrous levels the floor feels like an earthquake. Power has never been a problem either, I drive them with a Rotel 200w per channel amp and have never clipped them.
But while they can go loud, it's really about a clean, articulated response that make your main speakers feel larger and opened up. Not chest-punchy car sub competition bass. (But with this much headroom, you can EQ whatever bass response you want.)
If you can do this...DO IT!
Anybody else remember The Cult of the Infinitely Baffled website?
Can't wait to see where the scrap diffuser pieces end up.
Excellent!!!
If they sound half as good as they look they are still amazing!
Pretty good.❤😀
Very Cool!
What's it sound like in the room behind the speakers when it is going? That would be an interesting to see the response from inside the "box". That's a beautiful flat response.
cool video John,
what did you use for drivers? Eminence?
It looks like your woofers are overdamped. This is a common problem when using conventional woofers in an infinite baffle system. A typical good quality woofer has a Qts of between 0.3 and 0.45. When installed in an acoustic suspension cabinet, the air in the cabinet acts as an additional spring to reduce the compliance of the woofer and raise the Q to a more desirable 0.7 - 1.0. Without the small volume of trapped air, the woofer's Q stays low, and so it is overdamped. This is what's causing the slow rolloff you're getting in the deep bass.
You could either try woofers made for infinite baffle, with a Qts of 0.7 - 1.0, or you could simply insert some power resistors between the woofers and your amplifier. Assuming your woofers are 8 ohms each, and the two on each baffle are in parallel, you could add a 2 ohm 200 watt resistor in series. This would waste a bit of amplifier power, but it would also raise the Qes (and therefore the Qts and Qb) of the system, flattening out the bass response. You can find such resistors for about $10-20 each, so it's worth a try.
Yes, they are not the ideal drivers, but they are the ones that I have. Also adding mass will drive up Qts, but I'm quite happy with what I'm getting as they are. I may experiment further in the future.
Thanks for the comment, you obviously know the subject.
@@IBuildIt Actually, I think what your results show is an illustration of the difference between what people think they want and what they actually need. In your case the roll off is nearly perfect for your room as the results plainly show. People think they want flat extention to 20 Hz or below when actually a F3 of around 40 or even higher is much better in room. I will add the caution that without the rear air spring you may eat up your driver's Xmax relatively easily....Especially with movie soundtracks. I think you know this already as evidenced by the roll off on your EQed curve. Great video on a seldom covered topic!
@@russellanderson746 I've made several videos on the way to settling on this IB subwoofer setup, including measuring the the "safe" range of cone excursion for these woofers. If I thought this would exceed it, I wouldn't do it.
While this video stands on its own, it's worth watching the ones that lead up to it to get the whole story.
@@IBuildIt I think I've watched all your videos on this build(and enjoyed them). My comment on the Xmax issue was intended for others who may not be familiar with these concerns. I'm glad you're getting good results with the IB. The transient response should be outstanding considering Qtc should be very close to the Qts of your woofers.
One more thing....To anyone contemplating an infinite baffle install, be mindful of the effect that opening and closing the door to your listening room/home theater will have on the cones of your drivers....be gentle....slamming not recommended!!!!
Mr heisz
I am in new Brunswick and a friend built a infinite baffle for his theater setup
8 18" subs in a manifold mounted in his wall
Played the twister move and I was uncomfortable as in so real of a impact that I was scared.
I have never heard bass so strong smooth and extended
that response is freaking insane so much headroom you actually have to pull it back to get flat in the single digits!! lol
I can't recall if you plan to setup a tv in this room even only in stereo mode. It would be awesome to watch (and obviously listen) the latest Villeneuve's Dune release or his Bladerunner Sequel in this room.
What's the resulting f3 and total Q-value?
I like the look of the BAD panels.
7:10 Love it.
Hey John, great stuff.
SBA, single bass array!
Despite the fact I'm currently exploring all things open baffle etc., I'm an IB enthusiast/advocate as well.
I built an attic mounted (4)x18" IB firing thru a dual opposed manifold.
I also have two, double 15" SubMersives.
There's nothing like the bottom octave efficiencies that accompany an IB alignment.
An IB only needs a small fraction
of the normal power required for a sub... ~10%... that's huge*.
A typical high performance 18" sub driver may require a few thousand watts to hit full stroke in a typical sized enclosure.
My 18"s need only 200-300 watts to bottom at 30mm.
*(reducing power needed by ~10x dramatically lessens compression effects of instantaneous peak voltage drop from the breaker, the wiring, the amplifier, etc)
Even though the driver hits full stroke, distortion is lowered because those 10x efficiencies lessen current based distortions in the motor.
Le(i), Le(x), lessens both harmonic and intermod distortion (Klippel).
Also, power compression is equally lowered by 10x ... and that's mammoth.
Another big advantage is entirely eliminating SBIR, which plagues every system/room with freestanding speakers.
Thus, all that direct energy propagates forward, uniformly, without the impact robbing effects of boundary interference nulling.
Down low, IBs are excursion limited, not power limited.. so more likely to be damaged via bottoming, than burn up the voice coil.
As with flush mounted studio monitors, your flush mounted subs now increase the acoustic importance of your rear wall behind the listener. You'll likely need a ton of damping.
That's a lot but damn, I think your front wall is just the coolest!
The visual aesthetic... gorgeous natural wood tone, with the BAD like diffusion holes, is just straight up bad-assery!
I vote no black paint.
I find it particularly interesting because I'm currently rebuilding the front half of our room... heavy with wood slats, slots.
Thanks, all the best.
In my case, SBIR is a bit more complex. This wall is really just a 1/2" layer of drywall, since the front is covered with the diffusion panels. That's mostly invisible to low bass, so the wall behind this wall - 4 feet away and made from concrete - also has an impact. Not as big as it would be if this wall didn't exist, but still has an effect.
But the effortless increase in extremely low bass over the OB setup makes this well worth the time it took to do it. There's really no going back from this.
John, thanks for your video. Immediately I can say that your attitude is superb and your technical skills are adequate, far more than I can say about just about every other audio channel on youtube. So thanks for that. A bit more information about the room at the rear chamber would be helpful, as well as what sort of spurious vibrations are experienced in other parts of the residence while the new infinite baffle subwoofers are being pushed at normal spl.
I'd like to see an impulse response measure unsmoothed from that room! rt60 and rt 30 Im guessing the resolution is around 300ms for that room. how many cubic ft?
how the vibration of the supporting members? 2x4 or 2x6, will it transfer ?
Damn John that opening of the video was something else, I thought I was at the movies... :-)
I have a 6" woofer on my old 5.1 and it was bouncing across the floor... Lol
I like the built in the wall idea. I bet the whole basement vibrates the house...
I can hear it now. "What that's noise Ethil? Oh that is John down the road watching the movies again!" :P
Enjoy the work and thanks for sharing!
LLAP
My family room is open to the kitchen. My speakers are open baffle along the long wall. This gives me the idea... I can add an open baffle subwoofer that I place at the open end of the room and since no back wall it is now infinite baffle. Yes?
I love that old Sony startup. Sounds great when you have a butt load of watts a d good speakers
Sony...? You mean THX, right...?
@@aperson6955 Your right, THX. Sony used them in a project and I got them confused.
Maybe I missed part of the video but is the rest of the drywall braced? Does the wall vibrate at all?
I would love to learn woodworking on this level but I have no idea where I would start.
I'm wondering if the acoustics of the adjoining room have a similar effect on the speaker performance to the acoustics of the listening room?
No impact of any significance.
Consider this; those same woofers where they are, with a normal size backspace box enclosure.
That would be significantly impactful to the operation of the woofers.
Slowly increasing backspace volume diminishes the backspace effect on the woofers.
Thus, an infinitely large backspace has an infinitely small impact.
Infinite Baffle is really cool. I'm planning on trying it out in my car with a Ultimax 18 I have laying around.
Though my goals with bass aren't a flat response. It's an increasing level of output to the lowest areas my subs can play. Which currently is 17Hz in my car with my Ultimax 10. I like to have at least 10dB more output at 20Hz vs 100Hz. If it's low volume listening a little bit more than that. (In car low volume might be 60-70dB for me, I try to stay under 85dBA though that doesn't always happen)
In that case, a big vented box that's tuned very low is best. Or if you have the room, a very low tuned tapped horn, but it will be a beast, and is more difficult to design.
@@TimpBizkit That's what the 10" was. A big "vented" (Passive radiator in my case which functions the same) box.
The infinite baffle Ultimax 18 I put in my car is great because I have all my trunk space back with the same or similar output in the 15Hz range.
How long do you think the house will stand up to this low frequency assault on its structure ?
You probably talked about this in previous vids, but are you considering painting this room black at some point? That would give a feel of an ultimate home cinema. And ye, I know you like natural wood, but maybe in this case black would sute better? Also it would hide some irregularaties and flos in hole patterns, not that there are many, but there are some)
I talked about painting them black in a previous video, and I may do that. I also might take them off and recut the holes on my CNC so that they are perfect, and also a mixture of holes and slots instead of just holes.
But when I'm using the room, the lights are turned way down, so I can't even see those panels. Painting the entire room black would be a huge mistake.
What is the tool your using to cut your speaker whole
That's a disney THX opening. I can hear tinkerbell's silly fairy dust sparkle chimes overlay.
What's there in the room behind the wall ?? Is it an open space ??
How was the sound? I mean this soundtrack is very particular not every audio system can reproduce it properly.
Do you have an idea what is the flow resistivity of the insulation material you're using?
for depths larger than ~20cm / 8 inch you need to use fluffier and less dense stuff, something in the range of 3000-5000 Pa*s/m².
Otherwise if you use very dense material (10000-15000 Pa*s/m²), air/sound cannot penetrate all the way through and you would not absorb frequencies below 200Hz effectively.
Too much attention is paid to that and it really doesn't have as big of an impact as some assume it does. The difference in practical terms is negligible.
@@IBuildIt
Thanks for the reply, I haven’t really tested it out in any meaningful way. It’s just what I heard from other people and the simulations really back this up.
Most dense material plateau around ~20cm in simulations. Did you test materials of different densities / flow resistivity?
Generally the deeper the absorber, the less dense it should be. But most people don't have enough space to come close to the point where that makes a measurable difference. And then when it's measurable, that doesn't necessarily mean it's an audible difference.
Better to concentrate on area coverage, at least 15% of the room's surfaces, and make it as thick as practical.
The ultimate subwoofer is that one your neighbors can enjoy :D
MAGNEPLANAR will solve most everything. They do not do the very lows, even you have said can no longer hear. Great sound scape. Not cheap. First time I heard them was in 1974. Nothing compared to now. My "little" HPM-40's still outperform and a certain volume than most everything. The 4 year old Cerwin_Vega SL-15's are mud after 30 watts on an ONKYO high end receiver, though "capable" of 200 real RMS watts".
In your room, very nice by the way.....scalp a pare of magneplanar... sorry old school name... Magnepan 3.7i for your room size.
Sound Stage..........
Heart pounding........
Clarity.......
Pick out the location of each instrument, absolutely amazing.
John, even with your and my destroyed hearing from loud noise and tinnitus. These are your answer to enjoyment.
Be very careful. 100 watts may necessitate a foundation rebuild.! 400 watts and the house falls down. Large volume of air movement. That's why you "feel" the instruments as well as hear them.
hello, what does baffle subwoofers mean? stay safe always 😊
baffle is the plate you mount the subwoofers to
Should have shown below 10hz. I know some people dont care- but one the main points of open baffle is ULF- getting as low and as loud as possible
next make a flat plane bass array. It will reduce your room modes to just one.
Wait...stop.! I want to look at the cool compass again.... NEED IT..!!
you don't risk damaging the woofers by bottoming them out when you open/close the door to the rooms?
The door status will not make a difference, the woofers can bottom out either way.
IB 's are excursion limited, not power limited. My 4 x 15's can thermally handle over 2000 watts, my amp is set up to max out at 600 watts to limit excursion. Even with that, output is over 122 db at 20 Hz without room gain taken in to account.
I use a brick wall ( 24db/ octave) high pass filter at 15Hz to prevent over excursion and still have significant output above it.
If you build an IB, plan on having a MiniDSP or other parametric equalizer as part of your cost, you will need it to get the best response.
@@joesabato9736 not the state of the door, opening or closing the door
@@fuzzy1dk Thats what I was referring to by status, the door being open or closed. My IB array is in the unfinished basement firing in to the room through a floor grate. The basement is around 16,000 cu ft, even if was 1/10th of that size, the drivers could bottom out at real low frequencies.
@@joesabato9736 I'm talking about the action of opening or closing the door
@@fuzzy1dk
The action of opening or closing will make no difference.
Modeling my IB drivers with 180 watt input in WinISD, the excursion at 10Hz barely moves with change in box volume ( size of the room behind the drivers)
1060 cu ft size, excursion is 16mm
2118 cu ft size, excursion is 16.18mm
17500 cu ft size, excursion is 16.26mm
Xmax on the driver is 16.3 for reference
So whether the door is open, closed or in the process of changing anywhere in between, the impact on excursion is negligible, hope the numbers make it easier to understand what I was trying to convey above
It's all about the bass.
For me it's all about clean, even response.
Would you be running material over the front and rear to keep it somewhat cleaner?
Was hoping it was going to be Runnin with the Devil
Rock songs from that time period actually have very little low bass in them. Kind of disappointing when you have a well treated room to listen in and one of the downsides.
@@IBuildIt Just build a set of K horns or any horns will do for that matter, to compensate👿
@@IBuildIt Pink floyd, Comfortably Numb is a track that I use for bass response testing. As well as Bob Marley -Three little birds. You're right on rock bands not having much bass in them, especially Van Halen. The mixing on most of their albums ducked most of the bass, the same with Metallica, until ...And Justice, where they ducked just the actual bass (poor Jason). There's a few outliers though. Rush should have some good response.
@@robertbarcus1963
K-horns are excitingly impactful, but can be really weak in the deep bass... I believe in the mid 40s they drop off like a rock.
Headphones 🎧
shame you had to cut down the diffuser and instead setting back the woofers behind the diffuser mounted on the other side of the wall so they would be behind the diffuser and be hidden so you hear the sound but no sight of speakers
That would be cool, but I'd suspect the acoustic effect of the holes wouldn't be ideal, ie., they'd impede the output.
If there is an attic or unfinished basement above/below your listening room/theater, an infinite baffle subwoofer will offer you the lowest extending bass you have ever heard for the price of a midrange boxed sub ($1000). Its such a travesty that its implementation is so rare in amateur and even professionally designed home theaters.
?
He implemented an infinite baffle sub ... that's what this video is about.
@@FOH3663 Yeah, I watched the video, but did you actually read my entire comment?
@@conchobar
Absolutely, I read your entire submission, that's why I commented.
I too have implemented an IB sub, a quad 18" attic mounted manifold serving my primary system.
@@FOH3663 " Its such a travesty that its implementation is so rare in amateur and even professionally designed home theaters." What about that statement confuses you or you disagree with?
Just buy inwall subs instead