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Discussion Starter #1
Hello,

For my next project, I'd like to build a subwoofer into the wall where my television is mounted.
The television is mounted on a wall that is shared with the garage. Most of that wall is nothing but the garage on the other side. However, some of it is shared with the stairs going down to the basement. Then, there is a small section of the wall, which I've labeled in the picture below as "SUB??" which is actually a box, 3'x3'x8'. That box currently houses a single recessed light at the bottom of the basement steps. Picture (walls are thick black lines):

3039886


I want to turn that 3'x3'x8' box into a subwoofer enclosure (front baffle being the north side of that picture). I don't necessarily want the entire space to be used- I just want the drivers to be in the wall. So really, it would be either an in-wall ported subwoofer- port(s) opening into the TV room. Hopefully along with the drawing, this all makes sense.

Questions:
1) Can I take any sealed/ported design and build it into the wall, with the front baffle being that shared wall? Or does using the wall as the front baffle throw off the entire design of the box, as now it is an "infinite baffle"? For instance, I'd really like to build something like a THT or a Marty design into the wall.

2) Will using that wall as a baffle cause tremendous vibration problems for me, like I have to worry about my television falling off the wall? I know with enough power, you can blow the windows out, but that's not what I mean here. I'm talking about the physical movement that causes the wall to vibrate.

3) If I do use the entire space, can I take the volume and plug it into WinISD as the box volume? This kind of goes along with question 1, will the whole "wall as a baffle" make the modeling moot?

Thanks a lot in advance. Take care.
 

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no other options for sub (s) placements?
If not, make that thing IB, go whole hog
maybe 3 x21 or 24's
 

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Or
abut 12 of those 12" subs would fit in there . . .
 

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Discussion Starter #4
no other options for sub (s) placements?
If not, make that thing IB, go whole hog
maybe 3 x21 or 24's
Well of course I can put subwoofers anywhere I want, but the point of this thread was find out the effects of using that wall/area specifically, and how box designs would be affected by being built into a wall.

I've done a lot of reading, so much so my wife has to remind me dinners been ready for 30 minutes (whoops), all about infinite baffles. This isn't the route I want to take. I don't want to have to power 4 subwoofers and brace the wall all to hell and back. If it's a terrible idea to build a marty box or one of bill's tuba home theater boxes into the wall, I'm probably just going to build them outside of the wall as regular, movable units. This seemed like a fun idea to me.

Maybe my idea of infinite baffle setups are way off but it seems like you need a lot of moving mass/displacement, and a lot of power. Fun, but not what I'm going for in the living/TV room lol. Plus then I'd have to worry about sound leakage, and my neighbors are 10ft away from me on either side. Honestly if i wanted infinite baffle, I would have just made a manifold in the garage/ceiling/basement. Just not what I'm going for. Thank you though.

Or
abut 12 of those 12" subs would fit in there . . .
Now we' re just risking the structural integrity of the house itself, and I'm pretty sure that I'd accidentally blow the large window out on the right side of the room. Lol thanks for your replies though.
 

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1) sure you can. Is it the best location for a sub, who knows?

2)probably some, but not as much as you think.

3)No. Just pick a sub that has the output you're after and models well with a box size that fits the space.

4)be sure to post pics when you're done.:)
 

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that space will fit a SUBMAXIMUS V3, using a 21".
check out the build by @hd0823
 
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Maybe check the Devesatator Index and see it there's a good fit too... I bet the 4x JBL Dev would work well there, with pretty insane output.
 
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be advised that a V3 with a 21" will weight maybe a bit over 350 lbs.
but it's worth it
 
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Discussion Starter #9
4)be sure to post pics when you're done.:)
Oh I will for sure! Thanks for the replies.

Maybe check the Devesatator Index and see it there's a good fit too... I bet the 4x JBL Dev would work well there, with pretty insane output.
Devastator looks pretty cool, and amazingly cheap.
I'm considering putting servo subs in there for sound quality reasons.
I've never heard a servo subwoofer, though. I have no idea if the whole idea is even snake oil.
Subwoofer sound quality, driver vs driver is such a highly debated topic.

be advised that a V3 with a 21" will weight maybe a bit over 350 lbs.
but it's worth it
You're go big or go home my friend. I see that :) haha I appreciate it
 

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Discussion Starter #10
Heading out to cut a 'subwoofer maintenance access panel' in the garage so I can accurately measure this area. In fact, it could be much, much larger than I thought if the opening extends all the way up the stairs.
I'll be back with specifics.
If I'm not.... well I guess I fell or something.
I'll post pics of how it looks now.
 

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there is no guaranty that servo will play any better in that room than any other sub . .
 
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I figured I'd get that response. What is the purpose of servo subwoofers?
 

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Well turns out it is in fact much larger than I thought! It opens up into a large diagonal area that is the stair ceiling going to the basement. I'll post pictures soon.
 

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look up
Cult of the Infinitely Baffled,
that space and it's potetial need a smart look see
 

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Discussion Starter #16
look up
Cult of the Infinitely Baffled,
that space and it's potetial need a smart look see
I was actually thinking that now. I could throw a manifold in there. Might be easier that constructing a whole box. I'll have to measure the angle of the ceiling to get the correct size but I guarantee I've got 4x the vas of many subs. Would look sharp too with just one covered opening into the room.
 

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Discussion Starter #17
20200925_190645 - Copy.jpg

It's a pretty large space. Like I said, I'll measure it tomorrow and figure out exactly how large I've got. Those cobwebs are crazy too, lol

For tonight, I picked up pizza and we're watching some Soprano's. Have a good evening and thanks for the replies!
 

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Discussion Starter #18 (Edited)
Alright, I measured her today, and it is a big number.
My naïve self as a kid said I'd never use trigonometry, hahaha. :)

The easy one to figure out was the main, rectangular box. Easy- L*W*H. 38*44*82" = 137104in^3 = 79.3426ft^3
The wedge was where the trigonometry came in. I couldn't find the length, but I had the diagonal and the height.
Length = SquareRoot of (Diagonal^2 - Height^2).
L=sqrt(124^2 - 82^2)
L = 93"
Now to find the volume, since we know the length. I'm sure there's an easier way, but my teacher never marked me down for not showing my work!
(L*W*H)/2 = (93*44*82)/2 = 167772in^3 = 97ft^3

Total volume of the space is about 176 cubic feet which is 4984 liters.

That being said, I did some more reading on infinite baffles and I was dead wrong about the power requirements. Even though you're using more drivers, the amount of power required per drivers is much lower than it would be in a sealed box, due to the driver not having to work against the compression/decompression of air in the box. Sidenote: I could nerd out on stuff like that all day. This also brings up a drawback- I'll have to be extra careful I don't feed too much power to the subwoofers as they can more easily blow. There is nothing acting against them to prevent it. That is my understanding- I love learning if I got that wrong ;)

Finally, the thing that draws me most to the infinite baffle idea is having dual or quad opposed drivers to cancel out a lot of the physical vibrations. Brilliant.

New question:
-How would YOU go about making sure the space was ready for an infinite baffle setup? I don't want the ceiling falling down onto the stairs going down to the basement.

Of course, I'm going to do my own research and report back but if ya wanna chime in, it's always really appreciated!

Hope y'all are having a great weekend.

Edit:
So I'm pretty positive I'm going to go with either two or four Fi IB318 V2s. No other IB subwoofers seem to come close, pricewise.
Funny the direction this thread went!

I'd just like to make sure two 18s would be enough for the space, as I really, really don't want to do this again.
 

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Discussion Starter #20
Thanks, I did read that before and the part that stood out to me the most was when he said he thinks he should have gone with just two drivers, instead of four. That's really the crossroad I am at right now. I'll have to compare how large his room was vs mine. As I said, I don't want to have to open this back up to install more.
Life happens when you're making other plans, but I'd like to only do this one once :)
My Polish ancestors would be proud if I get this right the first time, HA.
 
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