Axiom Home Page Forums General Discussion Stereo In-Wall Speaker and adjoining room

I'm thinking about picking up a pair of M22 In-Walls.

I was hoping to hear from owners of Axiom In-Walls specifically in regards to what the sound is like in a room (bedroom) that is on the other side of the wall they are installed in.

Is it possible to add any type of soundproofing material during installation or do the In-Wall speakers rely on the wall cavity (since they don't have an enclosure)?

Thanks in advance for your time.

It is my understanding that the purpose of the enclosure that sits within the wall is to keep sound in the intended room, and not to interfere with rooms on opposite walls.

Randy has it right. The rear of the in-wall speakers is completely enclosed to both minimize the wall cavity's effect on the speaker's overall sound and to reduce sound transmission to adjacent rooms. Of course, it's impossible to completely eliminate transmission through the wall, but in reality any such transmission should be not significantly greater than a standard bookshelf or tower speaker placed near the wall.

Agreed with the above.
Of course adding some Roxul Safe n Sound or other similar product into the wall will help to a certain degree, but I think bass from a subwoofer will be your primary soundproofing concern - if you'll be using one that is.

When I built my room I planned for inwalls and one room is a bedroom, I did a double studded wall and filled with Roxul safe n sound there is more sound passing threw the bedroom door than the wall. If you have not yet bulit the room consider this but by the sounds of thigns you have it built already. Just stuff it with SnS.

Instead of some of the expensive methods like MLV (mass loaded vinyl), Acoustiblok ($$$$), Roxul, or the less expensive Audimute (which would be my choice if you don't DIY) you can use 2 layers of 30lb roofing felt from Home depot. If attached under the drywall you won't hear anything coming through the walls. This is what I'm using on my Porterplex V3 construction.

Oops. Deleting duplicate message.

Mass, damping, and decoupling. If tar paper worked as damping matter, then it would be used often in soundproofing. So far, I haven't read where someone has successfully used it, and experts say it doesn't work.

To the contrary, I have actually read many papers from Dr's in Acoustics, some that own Soundproofing business's of their own. It is all about what is impregnated within the felt, not tar paper. In addition, there are many people on AVSforum, Hometheatershack, to mention a few that would beg to differ with you.

Ok. I'll have to re-evaluate what I read, or thought I read on that topic.

Thanks for that tip Randy. Roofing felt is a new one for me. How do you apply it for soundproofing? Do you staple it to the studs and then screw up the drywall like usual? Does it work by decoupling or damping or...?

When I built my HT I used the 2x6 with 2x4 uprights double studded wall with Roxul which I thought was fairly cost effective. However I will likely be helping my brother build an HT this year so the more means at our disposal the better. Perhaps that could be combined with the 2x6 walls - just starting to think out loud now...

Here's what it is I remember reading from avsforum about the ineffectiveness of roofing felt.

What you did works great Dan and I thought about doing that, but was limited on space and didn't want to reduce the size of the pool table room. Decoupling is one of the major keys to seperate the two rooms involved. Actually air is best, why some create two seperate walls.

Here's another article on soundproofing with roofing felt. The article describes how to do it in a positive fashion. Then it's followed up with a reply saying that no one should attempt to do this in the inhabitable part of a building because of the carcinogenic gasses given off by the paper.

That is one of the articles I have read in the past. I am not using standard roofing felt, but rather a organic felt made of recycled materials and saturated with impregnated asphalt.

Ths product, manufactured by GAP, proposes no health hazzards. You can read the MSDS sheet if you want.

So the asphalt babies will just live behind the wall, too?

I'm all for finding a way to increase the soundproofing quality. After reading that, I'm still not clear as to it's carcinogenic qualities. "Inadequate Evidence that bitumen's alone are carcinogenic to humans" doesn't leave me feeling all warm and fuzzy.

They only become a problem when they grow up to be asphalt teens and start sticking their "things" through the wall outlets.

Further studies I've just read say that there is no evidence that exposure to asphalt (bitumen) fumes is a known carcinogen. But they advise to only be around it in a well ventilated area. HT rooms probably don't qualify as a well ventilated area. But if it's on the in-side of the walls, there would be little exposure, I guess.

Just go with Green Glue or ASC WallDamp under a second layer of drywall.

The MSDS mentions this manufactured product as protected and when used under ambient conditions poses no health hazard.
However, if the product is heated beyond 200 or if it catches fire, then, the major constituent asphalt (bitumen) will emanate slightly toxic fumes.

I've discussed via IM to about 4 others that have used a similar product, one person even used 90lb felt, and the only thing heard once in awhile at very loud levels was his dual svs subs. Only time will tell, not to worried about it.

1. Did they use 1 or 2 layers of this stuff (same side of wall)?
2. Was it on both sides of the wall (with 1 or 2 layers on each side)?
3. Did they also use DD and GG?
4. Did they decouple in some way also?
5. Did they use staggered studs, or a double wall?

Curious minds want to know.

One guy that used the 90lb role (very heavy and hard to find) just put it under the drywall on the home theater side, as well as above the ceiling drywall.

One guy that used the 30lb roles like I have from Home Depot put it under the drywall on both sides of the wall and ceiling.

Another guy took a lot of time and weaved the first layer around each stud to the halfway point of each cavity all across the wall to form a barrier at the half way point, then a second layer above that under the drywall. I tried this and it was not easy to work with.

For me I am going to try just putting a layer behind the drywall on each side of the wall. Since the material is 30" wide I will have to cut sections and overlap as I go across. So far I have been stapling and havent' decided if I'm going to use sealant/caulk yet. I think the drywall should hold it pretty flat. Who knows it might be a waste of time.

At the least, it might keep the ghosts and evil spirits out.