Material To Deaden Sound

[Steve Kalle]

I am looking at the various Owens Corning 703 & 705 boards but everything I see is designed to cut EITHER low frequency or high frequency, but I need something to reduce sound coming from outside my studio door. I can hear people talking and keys clanging around when they walk by. The studio is in a city's town hall so there is no way of preventing people from walking past our door. My idea is to use velcro to adhere the material to the door and have it overlap the sides of the door. If it matters, the room is 25x15, has carpet floors, drywall on left/right and cinder block on front/back and has a drop ceiling. The front is where we shoot and the edit bay is in the back.

What about the pink foam insulation at Home Depot & Lowes? I was told that this foam board works great to reduce sound in general.

On a side note: with the drop ceiling, what benefit, if any, would there be if I cut sections from the OC 703 1inch and replaced the drop ceiling sections directly above where the talking heads sit?

Thanks

[Jon Fairhurst]

Is this 703/705 material for absorbing sound in the room, or isolating sound outside of the room?

Lead sheet is often used for isolation. I have no idea about cost and availability.

[Steve Kalle]

The OC material is for absorbing sound, either high or low frequency. Here is the site that I will buy from: Owens Corning 703 : Ready Acoustics!, Hear - Sound - Better

[Seth Bloombaum]

I'm no expert in this, but, you do need to cover some basics.

Isolation is different than absorbtion of reflections. You use different materials.

People walking around outside but heard inside is an isolation problem.

Rigid fiberglass board's primary use is for reflection issues. Mass is what tames isolation issues.

Drop ceilings are notorious for transmitting sound. Your problem may not (only) be at the door. Get on a stepladder and get your ears near the ceiling when it's noisy and see what you hear up there.

Take a close look at the t-bars that your ceiling panels are in. Is there a t-bar running along and touching each wall? This indicates a wall that goes all the way to the true ceiling (good!). Does it look like the t-bar pattern just continues over the top of the wall? That's bad because it indicates you have plenum space in common with other offices or common areas, depending.

There are ranges of remedies, but do be sure you know what the problems are before throwing solutions at them!

[Bruce Watson]

Originally Posted by Steve Kalle

... I need something to reduce sound coming from outside my studio door. I can hear people talking and keys clanging around when they walk by. ...

The problem you have is that your space is physically connected to the space where the noise is. Seems like I'm stating the obvious, but it really is about that simple.

One of the biggest problems is that steel is an excellent conductor of sound, and your building is almost certainly made of I-beams. You can cover your walls is all kinds of things trying to knock the sound down only to have it transmit beautifully through the floor and the ceiling on I-beams. And let's not even talk about the evils of HVAC systems -- ducts are amazing at transmitting sound. As are water pipes and electrical conduit.

The classic way to fix this kind of problem is to build a room within a room. The walls and ceiling are spaced away and do not touch the building at all -- not even HVAC ducts, or electrical conduit. The floor is built on top of special reinforced sound absorber pads. I seem to recall that there's special plastic flexible water pipe for use in sprinkler systems in sound stages and recording studios.

You can go as far as you like to isolate from the noise. You probably won't want to go this far. The question is, how much is enough to get what you want done?

The person who can answer that for you is a local acoustical engineer. Someone who has the training and experience in noise transmission in buildings. And who is local to you so they can inspect your individual situation and make valid recommendations.

Or, you could just start slapping stuff on the walls and curse a lot when it doesn't do much. Which is what I did. I can tell you from experience that it's not a lot of fun. But it will make the acoustical engineer laugh when you finally do call -- you won't be the first he's seen do that.

Knowing what I know now, I suggest floor to ceiling heavy drapes across the entire entry wall, including the door. Space 'em off the entry wall a bit so they don't touch it, and make sure they overlap by a foot or more where each side meets (hopefully, in front of the door so it's easier to get in and out when the drapes are in use). Drag on the floor and ceiling, and make a seal with the two side walls. This will at least knock down the air transmitted sounds (cracks around the door, light switch, etc.). Just pull the drapes when you want it quieter. If you don't want to call an acoustical guy, that's where I would start.

[Jon Fairhurst]

Seth and Bruce offer the two parts of the solution: decoupling and mass. The top solution is the room within a room, including lead sheet. But that's expensive.

Calling an expert sounds like a plan. I would avoid spending money on fiberglass. It's for absorbing reflections, not for isolating external sounds. An expert should be able to let you know what will and will not work.

[Allan Black]

Steve .. Bruce has nailed it (no pun) call an expert .. without a doubt you'll save those costs and more.

If you're paying rent to the city then they approved your operation and it's not satisfactory. From the sound of the problem you'll need some specialist work done and they'll probably have to approve that too.

So you may be able to get help from the cities acoustic consultants or at least get pointed in the right direction.

Remember you can't fight city hall .. but you can do it once and do it right.
Cheers.

[Marcus Marchesseault]

There are modular sound booths that can be put together inside your office. They cover all six sides and have their own ducting. They may not be cheap, but they accomplish the room-in-a-room function and look professional.

[Dean Sensui]

Check out Sheetblok, made by Auralex:

Sheetblok Sound Isolation Barrier - Acoustic sound studio construction products from Auralex Acoustics.

Description of the material and its application are on the website.

[Allan Black]

Originally Posted by Marcus Marchesseault

There are modular sound booths that can be put together inside your office. They cover all six sides and have their own ducting. They may not be cheap, but they accomplish the room-in-a-room function and look professional.

Hi Marcus looks like the OP is using his 25'x15' area as a sound stage, don't think you can buy booths of that size.

[Jon Fairhurst]

Sheetblok looks perfect. It uses the same principle as solid lead, but presumably avoids the environmental risks of lead.

I see that they have another version (Sheetblok Plus) that includes an adhesive backing:
Sheetblok Plus Sound Isolation Barrier - Acoustic sound studio construction products from Auralex Acoustics.

[Marcus Marchesseault]

Just make sure to note that the adhesive is not meant to be permanent.

I seem to recall a study done with results that sound isn't blocked by a material so much as the change in material's densities. I guess this is why a layered approach is often best.

BTW, the first thing you should do is put something under the doors. An amazing amount of sound goes under doors, especially if the floor is hard. A gasket all the way around the door is also a good idea if it is not already installed.

[Jim Boda]

Originally Posted by Steve Kalle

...., but I need something to reduce sound coming from outside my studio door. I can hear people talking and keys clanging around when they walk by. The studio is in a city's town hall so there is no way of preventing people from walking past our door.....

Thanks

This is considered an isolation problem. Although, there would nothing wrong with adding broad band absorption outside of the studio...the real problem may be the door itself.

Studio doors are traditionally 3" solid core with complete gasket seals from top to threshold.

What door do you have?

[Steve Kalle]

Thank You All. I really appreciate all of these responses.

Here is some more info about my situation:
-- the studio is for the town's gov't access channel.
-- the studio is located in the basement of a 2yr old $50 million town hall.
-- the only people walking past our door are the maintenance guys.
-- the drop ceiling is the 'good' kind
-- we need the drop ceiling because of all the hvac and pipes in our ceiling and now there is barely any noticeable noise coming from them.
-- the studio door opens into the room and is solid metal.
-- the studio door has absolutely no air gap around the edges when closed.

The sound coming from the hallway outside the studio can only be heard through the door. The amount of sound is not very high but would be easily picked up by our lavaliers.

My original idea for 'isolation' was to build a frame with 2 perpendicular walls that go from floor to one inch from the ceiling. This 'corner' frame would be moved in front of the door in the studio to block sound coming through the door when we are recording. I was thinking of using the 1" pink foam insulation from home depot and use 2 layers on each side.

[Jim Boda]

I would be much more tempted to add a second door w/ an air gap between the doors to produce the impedence change, density, and air tight seal necessary for isolation.

I wouldn't recommend pink foam as an isolation or obsorption material (it would be reflective). You need a material that has a greater density...Dry wall, or durock (cement board).

The 705 material or equivalent 6 to 7 lb density Fiberglass material is excellent for a drop ceiling and you can add isolation to it by glueing 5/8" drywall to the top side of it.

Oh yea, and add on "On Air" recording light outside of the studio to let those key clanking maintenance guys know that you are recording.