a questions about sound-proofing your basement (1 Viewer)

[Rob Michaw]

Currently, my home theater is in the basement of a two-storey home. I havne't done "anything" of significance to quiet the theater from the rest of the house, but since my house is old (75 years), my wife and son cannot hear anything when I am watching movies at near reference levels (-10 dB) when they are asleep on the second floor. So my question is now this...

We are looking at moving, and potentially to a bungalow/ranch. With only one floor between us, how much sound proofing will I need to do? I am willing to invest some money and time to get it right, but to what extent will I need to? For a theater roughly 200 sq ft, how much money will I need to spend to turn an average drywalled room into a vey quiet drywalled room (not using any expensive 3rd party boutique materials)? Do any of you have similar stories? What are your results? Can your theater be heard in the adjacent/upstairs room? How much so, and how much quieter since the "sound proofing" took place? Can a young child sleep through the sound now?

Thanks.

 

[Wayne A. Pflughaupt]

I can’t give you any estimates, but I can tell you what needs to be done and you then you can do the necessary calculations.

The absolute best and most effective way to sound proof is to do it the way recording studios do it. It's all technique and doesn't require much (if anything) in the way of "boutique" materials.

Essentially this requires building a room within a room: A few inches out from the existing walls, and a few inches below the existing ceiling additional, free standing walls and ceiling of 2x4 or (even better) 2x6 construction are erected. Double sheetrocking is applied, and both walls are all fully insulated. The two structures must be completely and physically isolated from each other for maximum soundproofing.

It’s a good idea to apply a second layer of sheetrock to the existing walls and ceiling before construction begins. Even better, first tear out the sheetrock and insulate it fully before installing new double-layered sheetrock.

The new interior room absolutely must be airtight, so it’s a good idea to apply a layer of caulk between the sheet rock and all studs. The double-layered sheetrock is staggered so that you don’t have at any point straight-through access to the underlying studs. If the interior room is not airtight, soundproofing will be compromised.

There will now be two doors entering the room, and they should both be heavy, solid-core. They both must be fully weather-stripped and airtight, including an airtight threshold for each.

There will be specialized A/C requirements. Since the room is airtight there will have to be both inlet and outlet ventilation in order for the AC to function properly.

Keep in mind, however, that even all this will not absolutely eliminate leak-through of the lowest frequencies (although they will be reduced considerably).

If you can live with merely improved soundproofing rather than near-absolute, there are other more cost-effective solutions. If no one replies with their ideas, try this link.

Regards,
Wayne A. Pflughaupt

 

[Rob Michaw]

Wayne -

Thanks for the post. I do understand what you are talking about, and it even appears possible for me to achieve it. Your response has prompted a couple of questions for me though.

1) How can free standing walls support any weight? (i.e. hanging rear speakers, posters, drapes etc. or accidental leaning on a wall by a person, not to mention hanging doors)
2) If you double side the ceiling, how do you run electrical through there to provide lighting?
3) How do you bring in A/C or heat? If you link up the vents from the outside wall, don't you then give a channel for the sound to escape again?

Thanks.

 

[Wayne A. Pflughaupt]

Rob,

I must say I’m impressed – most people, when I spell this out for them they’re backpedaling in a hurry!

I can answer a few of your questions.

If you link up the vents from the outside wall, don't you then give a channel for the sound to escape again

By the time the sound travels all the way through the air ducts, into the main unit, back out again to the other areas – don’t think they’ll be much left to hear by that time.

Regards,
Wayne A. Pflughaupt

 

[Erik Farstad]

I too built a theater in a basement and documented the ENTIRE process on my website (follow link in sig). Wayne's sharing of a "room inside of the room" is the best approach for complete sound isolation, but if you don't want to do that there are still many things you can do that will help reduce sound transmission. I do much research and reading and then picked and chose as my budget and desires dictated...most importantly have fun.

E

 

[Wayne A. Pflughaupt]

delete

 

[Michael Whitney]

Erik,

You site is an excellent visual primer for all of our theatres. It is a great reference for all. Thank you for keeping it up.

 

[Travis_R]

Indeed, Erik has some great Ideas, a few of which I have implemented in my theater as well, in my ceiling I used the R19 Insulation between the joists and then put the Resilient hat channel over them like he did, I was going to use roof felt on the joists as well but decided against it, I have trouble getting people over here to help me and I couldnt do it myself on the cieling, I did however put the 90lb roof felt on the studs walls that are not exterior walls, I figure since my exterior walls are 2x6's and the outside is brick that I probably didnt need it, and yes a big thanks to you Erik, I have used many of your Ideas in my theater