In-Walls in ICF Construction

[snmhanson]

I am trying to get some speakers to go serve as general speakers for a zone in a whole-house audio system. They may also serve as rear channels in a 7.1 system in the future, so I am going with the company that I intend on purchasing the remaining speakers from as well (Paradigm). I think I want to use in-walls or in-ceilings for these particular speakers as there is just no room for bookshelfs where they need to go. Therefore I think I am going to go with the Paradigm SA line to ensure I have enough capacity in the event that they are used in the 7.1 system.

Anyway, the construction of the room that they are going to go in is ICF walls with a regular joisted ceiling. For those who don't know, ICF walls are concrete sandwiched between styrofoam blocks. In other words, the walls are 4" of pure foam and then 8" of concrete. I intentionally used the thicker 4" foam on the interior wall to allow plenty of room for deep electrical boxes and whatever else needs to fit in there.

So, my two choices are cutting out some foam to create a cavity for an in-wall speaker (and having to drill a channel through the foam and top cap up to the ceiling cavity to fish the speaker wire through), or simply using an in-ceiling speaker. I am thinking I would prefer the in-wall option as the positioning would provide better sound dispersion - especially if they are used for rear speakers. However, I'm not sure if the foam and concrete walls will hurt or help the accoustics. I assume they will help but I am not too keen on accoustics and sound pricipals. The in-walls would also help isolate the sound from travelling up to the second floor when compared to an in-ceiling speakers. The in-ceilings, on the other hand, would be much easier to mount but I do think I would be making sacrafices in terms of the overall sound field in the room.

What do you guys think? Do the in-walls sound like the way to go and will they work well with our construction type? Or should I stick with the in-ceilings?

Thanks,

Matt

 

[AVRat]

Paradigm specs provide the Minimum Internal Volume Required for the speakers and it seems anything larger than the SA-25s may require some extensive work to obtain the volumes beyond what the cutout dimensions portend. Depending on how your room is laid out, I don't think there's much detriment to using in-ceilings for the back-surrounds.

 

[snmhanson]

Paradigm specs provide the Minimum Internal Volume Required for the speakers and it seems anything larger than the SA-25s may require some extensive work to obtain the volumes beyond what the cutout dimensions portend. Depending on how your room is laid out, I don't think there's much detriment to using in-ceilings for the back-surrounds.

Thanks for the reply. The room layout is what part of the issue may be. It is a 28' long room and the primary listening/viewing area is just about in the middle which would put the speakers about 14' away from the viewing area. We have a pool table and game table near the back wall which will be the primary use of those speakers. However, I am wondering how well in-ceiling speakers would function as rear surrounds from that distance if I choose to use them for that purpose. Would in-walls aimed more directly at the listening area work better? Maybe it's not too big of a deal.

Concerning the cavity requirements, I did see those requirements on the paradigm website but didn't do the math. If I took out the foam behind only the cutout it would give me only .2222 sf and the speced minimum is .71 sf. I figured I would have to take out about 26"x12" of foam to get an appropriately sized cavity. Removing some extra foam behind the drywall shouldn't be too tough. It would really only be about 7" above and below the cutout and 2" on each side. It would be a kind of messy job to say the least, but I am sure I have the tools to do it. The real trick would be to fish out the wire which is hidden in the ceiling above, but worst case I will just cut out a small opening to work through and then cover it back up. I think I am going to beam the ceiling eventually anyway to it shouldn't be too big of a deal.

So, assuming I can create a large enough cavity and I'm up for the chanllenging installation, is there anything else that would be a deterint in using in-walls for this application? If I can achieve a large enough cavity, how will the speaker perform with a concrete slab behind it and foam all around it? Will it help or hurt performance?

Thanks,

Matt

edit: I also should mention that I would probably go with the S-30s for an in-wall solution and probably SA-15s if I am forced to use in-ceiling speakers.

 

[AVRat]

I really don't see any detriment to using them. Personally, I think the SA-25s are more than adequate, but that's your call.

 

[snmhanson]

Thanks again for your help. I may end up going with the SA-25s but I also may be able to get a good deal on a pair of SA-30s. Additionally, I am thinking the SA-30s will be a better fit if I end up using them as rears for my planned surround sound system of Studio 60s and ADP sides. I am sure I wouldn't be dissapointed with the 25s either though so I guess it just depends mainly on the price difference between what I can get them for.

Matt