Hi all,

I hate to ask this but after searching through the threads, I am confused on some things.

First: Sound Isolation
My room is roughly 14x19 with 9 ft ceilings in some areas and 8ft around soffits. The theater is in my basement so really keeping sound from above is my main goal. The room is framed and elecritcal work starts next week. I am planning on using fiberglass insulation in the theater walls/ceiling and also the ceiling of the whole basement. Most walls are 2x4 so R13 was what I was planning to use.
1. Will the use of Accoustical caulk around the walls be any help? Like on the floor plates or where 2 walls meet?
2. I don't really want to use 2 sheets of drywall. Can the use of a type of wall treatment be help in isolation or is this just for acoustics in the room?
3. I see fiberglass panels wrapped in fabric used a lot. Is this for sound isolation/absorption.

I am trying to get the most sound isloation/absorption as I can for the money.

Second: second row seating
My wife actually wants 2 rows of seating and we are planning on getting the Coaster Showtimes. Do most allow the second row enough room to fully recline? You need 26" in front of the Showtimes to recline fully. This is more space than needed for just getting in the seats. I believe we have the room for this but wanted to see what most do. I am unclear if the seats allow for a partial recline on the seat back without hitting the front row with the foot rest.

Any help would be greatly appreciated
Thanks

For the walls, you can use 1/2" 'sound board' between the framing and sheetrock. I didn't think to do it on my exterior walls, but they are R19 anyway. But when I decided to add a wall between the back of the LR/HT and the dining room, I put one layer of sound board on each side of the wall and then 5/8" sheetrock. You could probably use it on the ceiling.
Just make sure you use longer drywall screws, at least 1 3/4", instead of the typical 1 1/4"

Not to sound stupid, but what is sound board?

Acoustical caulk might help, but IMO if you're not doing 2 layers of drywall it may not be worth the effort or expense.

Wall treatments are usually thought of just as in-room acoustic treatments for absorption, and not particularly useful for isolation. Seems like any sound getting absorbed is sound that's not otherwise going to leave your room, but the general answer to the question is that the in-room treatments are not for isolation.

Second row seating: Yes, I would allow room for the second row to fully recline. Another thing to consider, though: I have the directors, rather than the showtimes. I'm 6'0" and they are extremely comfortable. However, when I recline all the way, my legs/feet extend an additional 12" beyond the front of the recliner. So if the directors are any indication, you may actually need about 38" in front of the seats to recline fully, and even then, you won't be able to use a walkway there while someone is reclined as your feet will be right at the back of the chair in front of you. The seats do allow for partial recline, but personally it would drive me nuts to be sitting in the back row and feel "crunched" and unable to recline all the way due to the chair in front of me.

Thanks for the replies.

Hmm, might have to look at the double dry wall again. Is it a all or nothing job? I guess if you do it, it should be all walls and ceiling? I just think my drywall guy is going to think I am nuts. Not sure what the additional cost would be...

BTW, I read a write up on the net that a guy used drop ceiling tiles wrapped in fabricover top of the drywall. He then trimmed around them to create panels. I noticed at Lowes today that they say they stop 55% of sound. Anyone used these? The guy that did the write up also did the double dry wall though.

Thanks

Not to sound stupid, but what is sound board?

Sound board is a fiber sheathing that is 1/2" x 4' x 8'. If I remember right, it is made by Celotex. It can be bought at most lumber yards, or home centers-Lowes, Home Depot, etc.
Here is another product I just came across.
http://www.supressproducts.com/products/index.htm?gclid=CNqq8r3GzIkCFR29YAodYW1DvA

Any benefit to using the double drwall on the ceiling only? Bleed through upstairs is my main concern. I am insulating the ceiling in the rest of the basement and the theater is on the opposite end of the house from the master bedroom. All other rooms are up on the 2nd level.

Is the double drywall of any use without GG? I guess I could do one layer and go simple on any trim. Then if it is not enough, go in and add another? Sucks to have a budget ...

Also, my screen wall and 1 side wall are concrete behind the 2x4 stud walls. There is about a 2" gap between the concrete and the stud wall. Does this help me at all?

Did you bother to look at the link in post #6?
Its a special drywall product, that they state, one layer is better than 8 layers, I think it was.

For the walls, you can use 1/2" 'sound board'
Worthless for sound isolation. Numbers like 50% are nonsense numbers which cannot be supported, and where it might apply is at the higher frequencies.

Two layers of drywall with green glue between the layers is a preferred method. If you're just doing the ceiling, don't bother. You must do the room...rather like building an aquarium with only a bottom.

I am aware of the genesis of the Suppress Product...it is good as well.

I did read about the Suppress product. I have requested some info but after reading about Quietrock and the prices per sheet, I figure it will be the same scenario. In the threads I read about Quietrock, 2 layers of drywall and GG was cheaper and as good or better than the QR.

We will be ready for drywall next week.

Numbers like 50% are nonsense numbers which cannot be supported, and where it might apply is at the higher frequencies.
This refers to what?

Maybe he was referring to the 55% number I said about the ceiling tiles I saw at Lowes?

soundboard will cut high-frequency sound only and should be considered useless for your application. lows and mids require serious engineering like double drywall with green glue. Dennis is an acknowledged expert in theatre design and construction and is quite right when he says (I paraphrase) do it right, or don't bother. If you don't also do your walls/doors then the low/mid energy will just propogate into the rest of the house anyway.

Yes, your walls and ceiling should also be stuffed with batt insulation. My preference is Roxul (rock wool or mineral wool) because it's very dense and also flameproof. Do the cavities beside the concrete walls as well.

I have not been on this forum long but I have read about Dennis :)

I started finishing out my basement a few weeks ago and just wanted a nice place to watch movies. I have a 53" Hitachi rear projection non-HD TV now and started thinking about a bigger TV. I read about the Infocus IN72 and decided I wanted one. Then I found AVS. I decided to step up a bit and do the Mitsu HD1000 w/ 100" screen.

Then I started looking at everyones HT designs and setups and was wanting that too :) I had already planned using insulation in the ceiling and walls. In my last basement, we finished it out and I insulated the ceiling for sound control. I have 2 kids and it sounded like a freight train upstairs before I added the insulation. Before the theater room was dreamt, insulation was already there :)

I guess I will be going with my original plan as there is no way to skimp and the budget just is not allowing any more.

Thanks for setting me straight.

"Two layers of drywall with green glue between the layers is a preferred method. If you're just doing the ceiling, don't bother. You must do the room...rather like building an aquarium with only a bottom." Love this analogy, Dennis!

Have been only visiting this forum for a few months, what an education I've received!

This one's for you Dennis, we are framing our theater, will start with dry wall soon, have the green glue awaiting application. Are having troubles finding a good sealant. USG is nearly impossible to find (I haven't yet), and the stock for sealant is limited at Lowe's/Home Depot. Any suggestions on finding a reasonably priced yet effective acoustical sealant?

Thanks in advance!

Liza

Liza:

If you're looking for something to seal between the floor and the bottom of the drywall, a 50 year caulk will do just fine.