False wall IB TC9 Floor to Ceiling Line Array

The TLDR question is basically that I've done quite a lot of reading about the various floor-to-ceiling arrays and it seems like there's nothing preventing it from working infinite baffle, but am I missing anything in my research? Comments & advice welcome... more details follow.



Mounting would be wall integrated baffle, into a rear area approximately 3500 liters that I can specify whether or not it is open to the attic. See picture for rough plan for implementation. Custom framing of "false wall" (actual wall that will have no structural need, but will completely isolate front and rear of speakers) will allow for the baffle to be screwed directly to (or through with T-nuts) studs. Open back, possibly make it semi-enclosed with some foam / stuffing / fiberglass just to keep any dust from settling directly on the rear of drivers. Room will be ~12x18ft rectangle with the TV approximately centered on one of the long sides. The area to the left of the left speaker would be a closet for equipment with a door further to the left. Area below the TV will integrate some wall mounted shelving that matches whatever I use on the decorative over-baffle that gets used. Either veneer or Corian or whatever my wife picks.

The wall mounting is a WAF haggled implementation. I promise no speaker boxes in the room and she promises to be flexible with what I choose to do with the wall. So something is getting mounted to the wall (and likely run IB), but aesthetics needs to be a consideration.

The main alternative to the TC9 array is using a more normal speaker, probably the Modula NeoD CC as L/R, as I have been sitting on parts for 2 of those since well before all the drivers stopped being manufactured. To get appropriate bass extension with those, I'd likely need to add in subs, which would go in the labeled areas either on wall or in a manifold, again with support custom framed into the wall. I think with the line array, I can get adequate output down to 30Hz or so without a sub, which would make everything so simple and elegant, and is a good part of why I'm leaning towards the line array.

Either setup will likely be driven by 2 Hypex amp / DSP plates that I would fab a box for them with a quiet fan and sit in the equipment shelves. If line array only, they'd run bridged 8-ohm, then if I determined I needed subs, could run a channel for main and one for sub each side.

I should note that I am pretty "casual" in terms of listening and HT uses. I like great sound, but I don't go overkill. Current speakers are basic vented 6.5 / 1inch dome 2 ways I hacked together quite some time ago and they run from the receiver amps... and realistically these are pretty adequate, despite being fairly mediocre drivers from a THD standpoint and the crossover being outright poor on phase alignment. Anything will be a decent upgrade, and implementing DSP will allow for response tuning to our liking. Planned output levels are decidedly sane, I don't need things to play at 100+dB.

Thanks for any help.
 

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I promise no speaker boxes in the room and she promises to be flexible with what I choose to do with the wall. So something is getting mounted to the wall (and likely run IB), but aesthetics needs to be a consideration.
Hi Concillian
I would like to give you an idea for an in-wall system with my MDD projects. I don't have the possibility to try it but it can also serve as a starting point for other DIY, the scheme is also valid for other omnidirectional diffusers.

The geometry of the MDD speakers allows it to be housed in a vertical niche to be covered with a cloth. The niche has two oblique walls at 45 degrees from the wall. With this configuration the rear emission is reflected in the room. The red drawing shows the direct sound emission, the reflections in blue.

For the 21M7 project which has a square base 80 x 80 mm, a triangular niche with a base of 240 mm and a depth of 120 mm would suffice.
 

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nc535

Member
2011-04-08 5:12 pm
NC
Checking the specs, I see the TC9FD has a relatively high Q and thus suitable for IB. The one problem I see with your plan is that both left and right mains will be IBing into the same space. That is OK in subwoofer territory but not ideal for higher frequencies. Thus I would suggest absorption on the back side of your IB arrays.

The TC9 requires a relatively high volume sealed. Other drivers can do well on much lower volume. For example, based on my own results, I would think you could make a sealed array with 32 SB65WAC25 2.5" drivers just about thin enough to fit inside a stud cavity and thus avoid the issue with IB. (it might stick out an inch or so) The SB65's sound delightful but unfortunately cost almost 3x the TC9s.
 
Hi Concillian
I would like to give you an idea for an in-wall system with my MDD projects. I don't have the possibility to try it but it can also serve as a starting point for other DIY, the scheme is also valid for other omnidirectional diffusers.


In practice the front would end up significantly wider than 240mm if you account for thickness of wallboard at a minimum, and wall framing at a maximum. Plus some addtional width to mount grilles. Not sure I want something that wide, as any additional width directly reduces the usable closet space to the left.



Also seems questionable on the ability to reach acceptable SPL for 80Hz crossover to sub when used in HT application. I don't need massive output, but I do need some. I suppose it could be tuned for better extension.



It's an awesome concept and I commend your design & creativity, but I think such a design would require more experimentation and more complicated integration with the contractors for framing & drywalling than I'm willing to undergo. I'm not planning rear access for this wall, so keeping the mounting simple and in a way that I won't need to tear into the wall later is valuable, this is where just flat mounting a baffle to the studs is such an advantage. All I have to do is tell the contractor to put studs where I need them and it's done.