In-wall speaker installation in an exterior wall. Can it be done?

bpotter

I'm building a new home theatre 7.1 system in a basement media room and am currently in the framing stage. My initial thoughts were to use Polk 265-LS (mains), 255c-LS (centre), 700-LS (surrounds and rear), and DSWPRO505 (sub).

I'll be using a projection screen at the front of the room which is an exterior wall with 2 x 4 framing, insulation, and a cement basement wall. This is where the 265-LS and 255c-LS in-wall speakers would be located. Surrounds and rear speakers will be in-ceiling speaker (I have 18" between ceiling and floor above and I wasn't planning on using enclosures).

Question..........unfortunately, my local Polk dealer told me that I should avoid putting the 265-LS speakers in an exterior wall because air movement behind the speaker was important and with insulation in the exterior wall, this would negatively affect performance.

I'm not sure I agree - but I can't find anything to suggest that exterior wall placement of Polk in-walls is acceptable. If possible, I would like to avoid building an enclosure as that would reduce the effectiveness of the insulation (although, if I have to, I will).

Has anyone done this successfully? Was it done with an enclosure built to allow for the Polk recommended 1.2 cu ft of air?

Thanks.

tonyb

You do need some air around them, hence the box. I take it your framing over an existing concrete basement wall ? Maybe a better alternative would be Def techs on wall speakers, slim, flat and every bit as good.

http://www.definitivetech.com/products/mythos-nine

disneyjoe7

How about adding a fake wall over the exterior wall. Would loose what 4" of room, but no issues on speaker being in wall.

kcoc321

You could create you own "performance box" to match the performance enclosure.
I would use a Hi density foam insulation behind the speaker "box" to keep the same R-value.
You would want to use 2X6 studs on that wall to account for the 2 1/2" of insulation
(@ R-6 per inch = R-15 which is as much as you can get in the 2x4 cavity you were going to be using)

Info on the "Performance Box"

NEW Polk Audio ENCL-LC65i Performance Enclosure

Product Features:

Constructed of high-density MDF, braced for rigidity, and damped with professional-quality, fire-rated poly fill material.
Fits easily between normal wall studs or ceiling/floor joists. Adjustable.
Rigidly reinforced for vibration-free efficiency.
Hides a perfect-volume, professionally damped enclosure right inside your walls, for the ultimate in stealth audio performance.
Performance enclosures guarantee the most consistent, most dynamic, full-spectrum high performance sound, with better low frequency extension and reduced audio “print through” (sound through walls).
Exact volume custom enclosure fits between studs.

Works with Vanishing Series 65-LS, 625-RT, 65-RT, LCi Series LC65i, LC65F/X, TC Series TC65i, MC Series MC65, SC Series SC65

14" W x 55 5/8" H x 3 3/8" D

bpotter

Thanks for the responses. Adding the additional 4" of framing sounds like it may be the best option for me.

I'm not sure I would need to build a full speaker enclosure if I did that. Would it make sense to add a layer of foam insulation which would sit between the studs at the back of the new wall cavity? This would provide a firm surface instead of the poly and insulation that would otherwise back the speakers in the existing exterior wall.

Msabot1

Check out Stealth Technology line of in walls ...low profile and very good for that ap!

StantonZ

I would seriously consider NOT buying (or placing) any "in wall" speakers. It will never sound as good as a floor/free standing speaker AND limits future options.

bmor

I would build the additional 2x4 wall in front of your exterior wall if you have the room. That way you can ensure your vapour barrier is installed properly on the exterior wall, you can add insulation to the interior wall for better R value and you will have a cable chase between the two walls if needed for future reference. You can always drywall the back of the stud wall cavity where the speakers will sit if you think necessary.

Midnite Mick

disneyjoe7 wrote: »

How about adding a fake wall over the exterior wall. Would loose what 4" of room, but no issues on speaker being in wall.

To me this is the best option. I did this on the main floor...not for speakers but just for running conduit in the wall for wires.

Mike

GospelTruth

I'm about to embark on my own theater room in the basement as well. I will be building 2x4 studded walls along a large portion of the basement which is concrete (walkout basement). However, putting 2x4 studs against bare concrete is not a good idea as the wood will suck out any moisture in the concrete. I will be putting up either 1/2 inch or 3/4 inch foam board sheets against the concrete first and then putting the studded walls next to the foam board. This helps insulate and keeps the wall from touching the concrete.

If you were to put a cavity in the wall for speakers, I would think this would be fine without any additional insulation provided you put in the foam board between the concrete and the studded wall. That's just my opinion though. I don't think you are going to have a terrible heat loss if you go that route. In this way you wouldn't have to build two walls.

You could also try building a 2x6 wall against the concrete to give it a little more depth and put additional foam board behind the cavity holding the speaker.

pdxfj

Do you have enough depth do make a screen wall?

My theater is also in the basement, although I didn't frame in the foundation walls since they were already finished with plaster and a heavy knock down texture. I built a screen wall 8 inches out from the foundation wall. I covered the foundation behind the screen with acoustical insulation.

See post #2 here: http://www.polkaudio.com/forums/showthread.php?147443

disneyjoe7

GospelTruth,

Why not use pressure treated 2x4's instead?

GospelTruth

disneyjoe7 wrote: »

GospelTruth,

Why not use pressure treated 2x4's instead?

You can use pressure treated lumber, but typically that would only be against the basement floor. Pressure treated lumber for the entire studded wall would be more expensive, heavier and wouldn't provide any additional insulation. All the forums I've been reading would use the pressure treated as the base of the wall (on the concrete) and regular 2x4s for the studded wall with the foam board as the barrier between the concrete and the studded wall.

I'm sure you can go with all pressure treated lumber, but I wouldn't want insulation up against the bare concrete either. You'd have to check out the building codes in your county or township to see what is acceptable.

I'll leave you with the following on insulating basement walls. It's one of many examples you'll find on the net about good ways to insulate basement walls.
http://www.homeconstructionimprovement.com/insulating-basement-walls/

Also check this link about vapor barriers in basement wall construction.
http://www.homeconstructionimprovement.com/vapor-barriers-for-basement-insulation/

Look under Hybrid Foam & Fiberglass Insulation to see the method that I plan on using. It does require that there be no sign of water in your basement at any time. For my home here in Nevada, not really a problem with water.

disneyjoe7

GospelTruth wrote: »

You can use pressure treated lumber, but typically that would only be against the basement floor. Pressure treated lumber for the entire studded wall would be more expensive, heavier and wouldn't provide any additional insulation.

But PT lumber wouldn't rot as I felt this is your issue.

GospelTruth

disneyjoe7 wrote: »

But PT lumber wouldn't rot as I felt this is your issue.

No, that's not my issue. I was just commenting that wood on concrete sucks out any moisture in the concrete. That's why building code requires PT lumber where it comes into direct contact with concrete. Studded walls on basements are normally built with either a vapor barrier or something in between the studded wall and concrete so that PT lumber isn't required. In my case I'm going with the foam board to act as the barrier and it also doubles as adding insulation.