In-wall speaker install advice

[dragon1952]

I posted this in the wrong forum earlier.
I'm trying to design my speaker placement and was wondering what the size of the in-wall speaker enclosure should be. Each speaker (RCi85) is approx. 14" H x 10" W. They will each fit between studs which are 14" apart so that will leave 2" on each side. I plan on putting 2 x 4's above and below each speaker to enclose them, and I'm thinking I should leave about the same distance as on the sides ... 2" above and below. So the speakers are 14"H x 10"W and the enclosures would be 18"H x 14"W. Does that seem OK?
Also, I plan on stuffing some insulation in each enclosure for dampening but not sure how much. Would a little bit do or would you cram it in?
I drew a pic showing what I had in mind. The top of the TV would be at approx 48" so I was going to install the speakers 2" above that so they would start at 50". That would probably put the tweeters over a foot above ear level but the tweeters are pivotable so I could point them down. Optionally, I could put the L and R speakers lower than the center to get them closer to ear level.
In the pic of the fronts, the R speaker diagram shows the 2 x 4's as they would look inside the wall.
The rear speakers, I was thinking about mounting them in the same manner but at around 56" and angling the tweeters down a bit as I've read the rears should be above ear level.
Any comments and /or advice is welcome.

[mark090852]

One thing to keep in mind...if the center is inwall and just two inches above the top of the tv you might be limited in your ability to switch to a larger tv in the future without the hassle of moving the center. Is a center channel speaker mounted under the tv or on top of it not an option?

[Cyan]

Hey Dragon1952, I too am in the process of creating some custom enclosures for some new polk in-walls. For my surround and rear speakers (RCi85's) I framed in an enclosure leaving about 3" space around the perimeter of the speaker. I created much larger enclosures for my fronts (lCi65's) and centers (LCiC). I then placed sound insulation in the enclosures (thinner directly behind the speaker) and placed a vapour barrier over it (As some of my walls are exterior walls). This weekend I plan to coat the inside of the enclosure with car undercoating.

I got the idea of car undercoating from the head car installer at Future Shop (where I work). I originally went to him in order to obtain some cheap Dynamat in order to deaden the enclosure and he told me how he has been using standard spray car undercoating for years with great success. I’ll let you know how things turn out on my end when I complete the rooms renovation on August 1st.

Best of luck, and please pass on any tips you come across.
Cyanavitch

[dragon1952]

Mark...I just got a brand new 42" plasma so hopefully I won't have to worry about it for awhile :D But yeah, that's the chance I'm taking by placing the center in-wall. I wanted all the speakers exactly the same.


Cyan.....sounds like you're ahead of me so I'll be looking for the tips from you :D What exactly are you using for sound insulation?

Scott...where are you bud? I figured yours would be in by now

[Defiant]

Have had some set backs with mother in law heart surgery and also been working my ass off. Mine are ready to go in since we now have power to the house :D If you make the enclosure so that from stud to stud the dimension is 22"-24" you would be happier I think.(based on inside volume) I thought mine was going to be studded with 2x4 but vaulted ceiling is done with 2x6 so I had to adjust my dimensions alittle. Everything else looks real good tho from the pic. Ill get some pictures off to you real soon of the house bro.

[dragon1952]

Hmmm.....maybe mine are 2x6's too cause it is a vaulted ceiling. I'll have to check more closely. So 22x24, that means I'd have to cut a couple pieces out? Never thought of that. I think I'll run up there now and check it out :D Thanks bud ;)

[dave shepard]

Hmmm.....maybe mine are 2x6's too cause it is a vaulted ceiling. I'll have to check more closely. So 22x24, that means I'd have to cut a couple pieces out? Never thought of that. I think I'll run up there now and check it out :D Thanks bud ;)

If they are an outside wall they should be 2x6, an inside wall would be 2x4 unless it is a load bearing wall which would be 2x6. I don't think you should have any problems with the sound comming from the center. In the inclosures you would want to also put some batting in there and put a back on them to stop or limit the amount of sound transfered into other rooms through the wall.

Dave

[dragon1952]

Well I went up there and checked. Both the front and rear walls are 2x6's I must have known that because I've measured them for the depth of the speakers but it just didn't register I guess. They are both interior walls, BTW. The front wall has the stairwell on the other side and the rear wall has my wife's sun room on the other side. The 2x6's are between 14" min and 16" max apart, center to center. I'll have to talk to my builder and see if we can hack them off and frame them for the speakers :D
Yeah, I was thinking of 1/4" plywood backing and some fiberglass insulation.

[Defiant]

You might want to consider 1 - 1 1/2" foam rubber. something that doesnt fill up the whole volume of the enclosure. Just a thought, thats what I plan on using. ;)

[disneyjoe7]

I little off subject but somewhat related.


I have a set of RCi65 to install in walls in my house that are walls but only in half, ok so the wall is drywall on 2X4 interior wall that has insulation to its back. The wall is open on the other side, these half wall are walls which have different ceiling heights. These ceiling height change areas have walls which are half built so the other side is insulated but open to attic. So I don't think adding a drywall in attic to box in this wall, as I think the Florida moisture could be an issue. But then again I don't what to open wall place a speaker between the house air and the attic air even if backed by insulation. Or should I be concerned.

[Defiant]

Yes Sir you might want to put a vapor barrier between speaker and attic(outside) air. FL air is heavy with moisture as you know, and even tho speaks are supposed to be able to handle it I would still protect them. Not to mention when your air conditioned air that will penetrate thru your speaks and mix with the warm air its going to condense on the speaks.

I had to re-read what you said and still not sure about the 1/2 wall stuff you were trying to explain. Are they just un-finished walls or designed that way?
Hope this helped some.

[dragon1952]

Wow Joe...I mean Steve...that was really hard to follow If I understand correctly, I think you'd lose a lot of sound to the back.
Scott, I think he means the wall on the other side is an attic wall with just insulation on it.

Hey Scott, it's really hard to find info on in-wall enclosures. I wasn't sure if you want to cram the open space with insulation or just throw something in there to dampen a bit. So are you saying just throw a bit of something in there?

[Defiant]

Ya dont cram the whole enclosure with insulation (not needed) Just alittle something for dampeneing. Im planning on glueing the foam rubber in place because its quick and no mess, and nothing gets down in speaks.

[disneyjoe7]

Well sorry I confused you all again, I try but not my god given talent.


So Pictures are worth a 1000 words... Help this doesn't confuse anyone.

[disneyjoe7]

The half wall I saying is drywall / 2x4 / nothing vs. whole wall where drywall is on both sides of the 2x4's as this is a wall to both rooms.

[dragon1952]

OK ... that's what I thought you meant. BTW, you might want to stick with pictures or maybe sign language in the future :p ;)
I'd be inclined to try and enclose the speakers from the attic side.

[dragon1952]

I was just thinking....... ......wouldn't carpet padding make a really good liner for an in-wall enclosure? yes, no?

[disneyjoe7]

I confused about the whole in-wall speaker feeling around here, that we all need a tight enclosure for best sound. Aren't Polk in-wall speaker designed for a normal wall cavity, with some insulation behind speaker to prevent woofer sound defections discoloring the woofers proper sound.



Now as to my open wall not sure but I like Defiant's idea of the "Vapor Barrier", but Dragon I like your idea of carpet padding. But thinking about this again not sure about the moisture thing about the Florida weather.


Also Dragon, I had that comment coming I opened myself up for that one.
But I have been given you the sign language think of the "International Love" sign, perhaps you didn't see / receive it

[dragon1952]

Also Dragon, I had that comment coming I opened myself up for that one.
But I have been given you the sign language think of the "International Love" sign, perhaps you didn't see / receive it

Umm, hey no offense man but I don't swing that way

[disneyjoe7]

No offense taken dud.


You're cool with me as I assume Dragon 1952 is a Chinese year thing, so I'm another Dragon 1964.

[dragon1952]

No offense taken dud.


You're cool with me as I assume Dragon 1952 is a Chinese year thing, so I'm another Dragon 1964.

You would be correct, oh fortunate one ;)

[dragon1952]

I confused about the whole in-wall speaker feeling around here, that we all need a tight enclosure for best sound. Aren't Polk in-wall speaker designed for a normal wall cavity, with some insulation behind speaker to prevent woofer sound defections discoloring the woofers proper sound.
:

I have seen references to in-wall speaker design where they specifically say they were engineered for the free air type of in-wall environment but nobody says how much space was used in the design. The air space is different if you have 8' ceilings and 2x4 construction or if you have vaulted ceilings of differing degrees and 2x6 construction or how far apart your studs are (or if the other side of the wall is an attic!) Most in-wall speaker manufacturers don't even really discuss it, they seem to talk about ease of installation and the fact that they are paintable, etc. I guess they figure us fools using them aren't that particular to begin with.
Polk makes mention of "Infinite Baffle Tuning uses the virtual enclosure of in-wall space for superior bass response". You'd think they'd give you the optimum space in cubic feet or something.
Whatever, there doesn't seem to be a whole lot of information available so that's why we're all sitting here scratching our asses I guess
Time for a brewski :D Later........

[disneyjoe7]

Thank you :)

[scottnbnj]

i don't know much about in-walls. though lc*i's have been on the list for the bedroom for a long time, i just haven't gotten to them yet. but,..

lc*'s used to have enclosure volumes in a "white paper" on the lc* pages. now it's called "cut sheet". i didn't see the equivalent under rc* series, but i'm sure customer service would help out.

aside from acoustic properties, you don't want to trap or encourage moisture in the walls that moves from the inside out any more than from the outside in. a couple of common ways this will happen is insulation packed against the sheathing on exterior walls and roof bays or when removing insulation, either not replacing it or by replacing it with something that doesn't breath. though i might be wrong, i have my doubts about plastic sheeting, undercoating, closed cell foam and even construction styrofoam found in building supplies for interior wall insulation, particularly if no consideration is given for moisture to escape from the cavity. i think i'd stick with insulations that are intended for in-wall/ceiling use for projects like this.

for dampening, in the roofing and window and door sections of building supplies you can usually find butyl or rubberized asphalt rolls of flashing tape. it might be a few inches wide by better than 15' long with foil facing. i've been thinking this would make excellent damping material, but again i'd leave space around it to let moisture travel through the walls naturally.

to make the enclosure air-tight, control resonances and fasten the blocking to the sheathing, i'd put a wide bead of construction adhesive (like pl-400) on the 2x sides of the blocking where it meets the drywall and sheathing.

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