VO-BB - 20 YEARS OLD!

cyclometh · Posted: Mon Mar 21, 2011 10:33 am Post subject: Sound isolation options

Hey folks- I find myself in need of a more sound-isolated environment than I can realistically get in my current space. I have a basement office which is fine as long as there's no sound of any note anywhere else in the house, but due to the poor isolation of one wall and the ceiling, any noise made upstairs or in the room next door can be detected.

For example, I can hear voices when people speak, even in relatively normal tones in the rooms above. I cannot detect *what* is being said, just the vocal "hum". The same thing happens with the room to one side of the space.

Some of these noise sources I can eliminate by simply asking people to be quiet or coordinating activities, but in the end I can't be demanding people walk on tiptoes; it's their house too. While it's quiet the place is actually quite nice for recording in, but the level of silence I'm discovering I really need for extended durations is not realistic when there's 5 other people who live there.

What it comes down to is I need to improve the sound isolation of my recording envirnonment from external noise sources.

I'd like to hear general advice or recommendations if anyone has them. The room is about 10x11 (I have exact measurements somewhere, I'll find them later) and has two walls of cement backed by concrete, one wall facing into a sitting-room area, but with a set of deep cabinets on the other side, and the fourth wall faces another room used as a bedroom. The floor is a tight-pile carpet with deep padding on concrete.

My current thought is an inbuilt booth along the back wall allowing me to create a much more isolated environment without having to make major modifications to the room itself. It wouldn't have to be very large, as I only do voice recordings; no musical instruments and so on.

Thanks for any thoughts you may have or advice.
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cyclometh · Posted: Mon Mar 21, 2011 10:59 am Post subject:

Couple of other datums that may be of interest:

The house is wood frame construction and sits on a concrete pad. There is no crawlspace.

The house is on a dead end street, with a watershed behind, unimproved city land in front, and the nearest neighbor over a hundred feet away. The nearest major road is at least 150 feet away.

Traffic is so light as to be effectively nonexistent. Pretty much every noise source that I need to address is inside the house.

I don't need something that will be totally silent if people are shouting upstairs; I need to make it possible to record if someone is carrying on a normal conversation.

Thanks again!
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Corey "Vox Man" Snow
http://voxman.net

Mike Sommer · Posted: Mon Mar 21, 2011 2:11 pm Post subject:

Wood frame homes transfer a lot of noise, especially between walls. This is due to the fact that most interior walls are not insulated, and the minimum thickness of drywall is used, most typically 1/2".

Since you're in a basement is the ceiling drywalled or is it a drop ceiling?
How high is the ceiling?
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Acoustics are counter-intuitive. If one thing is certain about acoustics, it is that if anything seems obvious it is probably wrong.

cyclometh · Posted: Mon Mar 21, 2011 2:18 pm Post subject:

ceiling is drywall. The entire room is done in a sort of textured putty of some kind. Looks like it was put on with a 3" putty knife.

The ceiling is 8 feet, maybe a bit over.

Edit: Found the measurements I did before:

Room is 10'2" (122 inches) W x 11'3" (135 inches) L x 7'6" (90 inches) H.
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cyclometh · Posted: Mon Mar 21, 2011 2:51 pm Post subject:

Whipped up a quick diagram of the room. The walls on the left and bottom of this diagram are poured concrete backed by earth, the one on the right has another room nearly identical to this one on the other side of the closet and the wall on the top faces into a large sitting room, although there are cabinets from floor to ceiling on the other side.

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Corey "Vox Man" Snow
http://voxman.net

ballenberg · Posted: Mon Mar 21, 2011 4:07 pm Post subject:

Hey Corey, Mike--

Since there's noise from both outside the room and above, I'm thinking a new set of walls inside the existing walls Then take down the sheetrock on ceiling, add pieces of sheetrock in the joist cavities, and build a new ceiling resting on the new walls.

The studs for this ceiling will go in between the joists which will then be filled with pink insulation. It's important there be no physical connection to the house above. I know from experience, believe me. It makes a huge difference.

The good news is that Corey is handy and can do this himself.

Oh, and replace door with solid door if it isn't already, and if possible, add second solid door to new framing--one opens out, one opens in--works great

What do you think, Mike?

cyclometh · Posted: Mon Mar 21, 2011 4:38 pm Post subject:

The door is a hollow-core luaun one. I thought that was required by code; no solid interior doors?

The idea of building a new room inside the one I have is one I've considered. For physical isolation instead of taking down the current ceiling, what about just setting a new one on top of the walls as you suggest and making it lower?

And is this a better option than building a booth?
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Corey "Vox Man" Snow
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cyclometh · Posted: Mon Mar 21, 2011 4:44 pm Post subject:

Here's the quick and dirty version of what I had been thinking of, although I don't have any specific objections to the idea of just adding new walls and ceiling and not building a separate booth.

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Corey "Vox Man" Snow
http://voxman.net

Frank F · Posted: Mon Mar 21, 2011 5:05 pm Post subject:

Treat the ceiling and interior walls with 2" JM insulation. Although many city/county codes do require interior doors to be hollow, there is nothing in the code(s) usually forbidding sliding glass doors. Check you local building code. Two sets will be required as you would likely desire a 6" (minimum) dead air space between the glass.

Frank F
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ballenberg · Posted: Mon Mar 21, 2011 7:00 pm Post subject:

I think you could just add a new ceiling if you can spare the height, but you'll lose a fair amount--I'll let Mike take it from here. I'm not an expert--just had a similar situation myself, learned by trial and error. Plenty of both.

ballenberg · Posted: Mon Mar 21, 2011 7:07 pm Post subject:

Hey Frank--What are your thoughts on how insulation would mitigate his issues?

Mike Sommer · Posted: Mon Mar 21, 2011 7:15 pm Post subject:

Well, if Corey had the ceiling height, 11 to 12 feet, I would say build a room in a room. But structurally you can not build a ceiling or a floor structure without a Rim Joist or Blocking. So you can not build between the joist above, even if it was free and clear of wires or piping.

I know of no Code that says that doors must be hollow core. A hollow core door is just a contractors way of saving a few bucks. Once upon a time that's all there were- solid core doors. As a matter of fact code requires fire rated doors in the corridors of any public building, and between the garage and the home. And that's certainly, an interior door.

One thing I forgot to ask, are there any AC vents leading into this room?

If you want to live in a little box, build the booth. But you may still need to deal with the ceiling noise.

If you're getting a foot fall from above, then you need to block off between any joist that run from room to room, and add mass to the bottom of the floor above. Caulk and seal every joint, crank and gap in the structure with a non hardening caulking. Then insulate between the joist, and double drywall the ceiling.

The walls will need pretty much the same treatment as the walls. You may need to widen the the door opening because 36" is the minimum width for a Fire rated door - which you will need.

You may need to add a second layer of drywall to the other side of the common walls to this room.

If it is just low end vocal rumble that you are dealing with, then this would be how I would address the problem.

If you need further instruction or details contacte me at
MikeSommerVO@gmail DOT com
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The Blog:
http://voiceoveraudio.blogspot.com/

Acoustics are counter-intuitive. If one thing is certain about acoustics, it is that if anything seems obvious it is probably wrong.

cyclometh · Posted: Mon Mar 21, 2011 7:39 pm Post subject:

Thank you all- Mike, I sent you a followup email per your request.
_________________
Corey "Vox Man" Snow
http://voxman.net

Frank F · Posted: Mon Mar 21, 2011 8:48 pm Post subject:

Mike is on the right track about walls (adding a second layer of drywall to the outside of the rooms wall) but failed to mention that the drywall should be de-coupled from the original wall.

As for the ceiling, there is another option,,, to fill in the holes and seal the empty space - use spray-in foam insulation. Not cheap at around $800.00 USD and available at most Lowes and Home Base as a DIY project kit, but it is fairly easy to work with.

Using rigid insulation will attenuate the walls to eliminate 80% of the outside noise. As for the ceiling approximately 50% of the low frequency noise will be eliminated.

Good Luck

Frank F
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Be thankful for the bad things in life. They opened your eyes to the good things you weren't paying attention to before. email: thevoice@usa.com

danbrantley · Posted: Mon Mar 21, 2011 10:01 pm Post subject:

If all the noise is coming from above...

Would the "identical room" next door be quieter? Is it below a less used part of the house?

Would it make any sense to start with the room above? Replace the flooring with a layer of playwood, caulked per Mike's instructions, then a high quality sound deadening pad and new carpet?
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