Could I have found the Holy Grail in CHEAP soundproofing?

[Hub67]

OK - so we are finishing our dedicated Home Theater in our new home. The room is 15' x 25' x 8' high - framed - has a single sheet of 5/8" drywall on the four walls with a concrete floor. The ceiling is engineered trusses and upstairs is hardwood flooring. Once the electrical is finished - the ceiling will be dry walled also. All of the walls/ceiling will be insulated as we can get 'behind' all of the theater walls. Doors will be solid core w/seals. No windows.

I've read just about every post and article on soundproofing the room without an unlimited budget. Most of the 'best' incorporate a "room in a room" type approach. I've ready that mass-loaded vinyl can help when sandwiched between two layers of drywall - isolating the vibration getting through. Since mass-loaded vinyl run about $2.00/sq.ft. I'm looking at about $2000 (1015 sq.ft x $2.00/sq.ft.) to cover the four walls and ceiling.

Here is my idea: What if I went to the carpet store and bought the cheapest (thinnest - about 1/8") carpet - with an extremely hard tight weave (like commercial) and cover the first layer of drywall - then applied a second layer of drywall over it? I can get this carpet for less than $0.49c/ft ... ... ... got you thinking? Wondering what if?? Could I have just found a way to soundproof (as much as possible) this room and save $1600?

So - thank you in advance for your thoughts!

 

[slipperybidness]

I think that approach really relies on the mass of the vinyl to change the resonant frequencies outside the audible range.

 

[Rickster71]

To answer your question honestly. It sounds like a lot of extra work that will have unknown or limited success.

With the 'Room in a Room' idea in mind.
A very effective and fairly inexpensive way is to stagger or offset the studs in the walls. This decouples the theater walls from the rest of the house and provides a greater area to add insulation. Seems like it would be less labor intensive than two layers of drywall with carpet in between.

NOISEPROOF YOUR LIFE® | Green Glue is what's often used between layers of drywall. Not sure how it compares in price and labor to a layer of carpet.

Good Luck

 

[j_garcia]

No, just like the rest who looked for the grail and the fountain of youth, you didn't find it unfortunately. Vinyl and carpet won't have the same characteristics, so I agree with slipperybidness that it will likely yield results in either helping in a narrow band and/or far less benefit than the vinyl that is intended for the purpose.

 

[Hub67]

Thanks Rick - we did look at this as an option. With the Sq.ft (1015) we need to cover I'm looking at about $1000 worth of Green Glue. I'm not opposed to using it - but am trying to see if there is a less expensive alternative to accomplish the same or similar results. Was even looking for a no-name brand type similar to Green Glue that might be a little cheaper.

We can not stagger the studs as they are already in place but I can get behind them to insulate. I have one layer of sheet rocked walls to work with (or on top of).

 

[Hub67]

Damn J - I thought I was on to something

I'm open to suggestions - what would you guys do with my situation?

 

[j_garcia]

It might work to some extent, but as mentioned, it is a lot of work to maybe find out it doesn't do what you want or have to do it again (or worse, find out it creates a different problem). One wall or all walls? I'd probably look at in room treatments (bass traps, wall panels) and good insulation in-wall at the stage you're at.

 

[Hub67]

J - I am working with GIK Acoustics (sent them room drawings) and am budgeting $1500 for this. Looks like I can get a pretty good set-up at this $$$ amount - am looking forward to their recommendations - and will follow them.

I would like (in a perfect world) to treat all four walls and the ceiling. I'm just trying to keep the noise - especially bass - from invading the rest of the house.

Suggestions for insulation?

 

[j_garcia]

GIK is exactly who I was going to recommend, so I think you're on the right track Maybe ask them what they think about you're idea? They'll likely have an opinion on the carpet concept as well.

 

[Rickster71]

My understanding is that GIK's products are more for 'in room' acoustics and not really isolating sound from the rest of the house.

 

[Hub67]

Your correct Rick - and since I'm planning on (2) Power Sound Audio subs XS30se - I'm trying to keep that bass in the room!

I'm open to any suggestions to help isolate the room - would like to keep this at or under $1000.

I appreciate the feedback! This forum is great - unbelievable the amount of knowledge on here!

 

[j_garcia]

Haven't used the stuff, but here's a thought:

Soundproof Sheetrock: Construction Uses, How It Works & More Info. - SupressProducts.com

Acousti-Board A Sound Blocking Material

Bass is tougher to keep in a room, especially larger subs that dig deeper. My former 15" Tempest was vented and would vibrate things on the other end of the house (open floor plan). The fact that you chose sealed subs may help some too, as I noticed my Empire rattled fewer things, though that may be due to the opposed design and very inert cabinet rather than just being sealed, and the XS30s are opposed as well.

 

[Rickster71]

Unfortunately there's no easy and cheap fix here.
All of the OP's questions were best asked before the framing and rock went up.

 

[Hub67]

Rick - the inside of the room is rocked. I have access behind every wall - the ceiling won't be rocked until after the electric is in. Then we will insulate all four walls and ceiling - add a second layer of rock on the four walls (with something in-between) and finish the ceiling.

Then GIK! I emailed them Tuesday with the room measurements (see below) - Bryan emailed yesterday with some additional questions - and again today. Since this room is a blank canvas - this is really helpful. Here is some of what he said:

The riser can be used but I would not do a Helmolz. That’s very narrow and tuned. I would like to use it more broadly by having the joists running front to back, insulated, and holes cut in the front as large as you can get them and still maintain the strength.

Seating position, try to stay out of the 40-60% range of the room length. Normally I’d do the first row at 62% of the room length from the front wall but that will push the back row likely too close to the doors to have a decent walkway. Might have to go 38% from the front wall for the front row and 33% of the room length from the rear wall to the back row. 120” diagonal at 9’ away (front row) is big but not out of spec.

So the equipment will have a 62” wide opening? Is it just in another room and this is a door or is it a built in? How tall? It’s smack in the middle of the reflection zone.

 

[MixmasteredAcoustics]

Not sure where you are at with this project ( I just saw this post and became a member ) but if you have any unanswered questions. I'd be happy to help.

Cheers,
Dan

 

[Hub67]

Hi Dan - welcome! I think I'm going to use 1/8" high density packing foam between the sheets of 5/8" & 1/2" drywall. It's sold in 4" wide rolls and I can get 500 linear ft. for around $150.00. I tried it between two sheets of rock and did the 'knock test' - definitely heard a difference! It had a much more solid sound than none.

Our HVAC is going in this week - Electrical right before Thanksgiving. Any suggestions are welcome!

 

[MixmasteredAcoustics]

Foam is the absolute worst thing... it is very flammable and does not perform nearly as good as acoustically designed insulation. An excellent resource for comparing materials is (I cant post weblinks yet, but google Bob Gold Absorption Coefficients ) check that out and you will see what I mean.

Best of Luck with this project!

Happy Thanksgiving!

 

[Hub67]

Hey Mixmaster!

The thing I see in your post is 'not perform nearly as good' which means it will do something? My goal is to reduce the amount of noise transfer as much as possible with the least amount of $$$ spent (I know - doesn't everyone?). The cost of the foam is about $150 for 2000sq.ft. It's 1/8" thickness between two layers (5/8" & 1/2") would provide some additional reduction?

Given the details I've put in previous posts - and what I'd like to spend what would you (or anyone) recommend? Would this NOT be better than just two layers of drywall?

 

[mtrycrafts]

Hey Mixmaster!

The thing I see in your post is 'not perform nearly as good' which means it will do something? My goal is to reduce the amount of noise transfer as much as possible with the least amount of $$$ spent (I know - doesn't everyone?). The cost of the foam is about $150 for 2000sq.ft. It's 1/8" thickness between two layers (5/8" & 1/2") would provide some additional reduction?

Given the details I've put in previous posts - and what I'd like to spend what would you (or anyone) recommend? Would this NOT be better than just two layers of drywall?

If your previous post was correct, 500 lineal feet and 4" wide, better re-calculate the total sq ft. I come up with 1/3 of 500 sq ft, not 2000.

And, cover only 20.8 lineal feet of wall 8 ft high.

 

[Hub67]

Oops - it's 4' wide