cost effective sound 'proofing' (1 Viewer)

I'm getting ready to start drywalling my theater and want to do some lower cost sound proofing to the ceiling. I was thinking about some fiberglass insulation between the joists and then double drywall. I'm not expecting it to be completely sound proof, but want to make it at least bearable upstairs. Should this do the trick?

What is the best way to 'double' the drywall? Screw up the first layer, and then glue the second? Use screws for both layers? Should the seams be lined up or should I stagger them?

Thanks.

Here is a link to w web page that I have found to be very helpful, to me at least. I'm nearing the end of my design work so I've been trying to determine how much sound proofing I really need. http://www.soundproofing.org/infopages/soundwalls.html If you scroll down the page just a bit, you will see a comparison of different types of wall construction and what the resulting sound proofing value is. Keep in mind they are trying to sell their products, but I think the information is still valid.
To save a bit of reading, when they mention calking. What they mean is that none of the drywall edges actually touch the floor, ceiling or in the corners. They leave about a .25" gap and then fill it with calk.

To answer your question, for double dry walling you would want to stagger the seams, and personally I'd prefer screw attachment over gluing, but I don't really know if there is a significant acoustical difference.

Hope this helps...

Hi Dan

You might want to consider using resilient channel, a 12 foot long flimsy sort of metal channel that "softly" mounts the drywall to the wall studs and joists. It "de-couples" the drywall from the studs, at least as far as acoustic enrgy and transmission are concerned.

At first I was a tad intimidated by resilient channel because it looked too flimsy to screw into, and too weak to hold the weight of drywall. But after a did a little test section, these concerns proved to be non-existent. It was easy to use, and surprisingly strong.

It's cheap to buy, easy to install, and if the studies by various acoustic labs are correct, effective in reducing the sound that makes it through walls and ceilings. I haven't finished my drywall, so I cannot comment on effectiveness yet.

There are lots of sources of info on resilient channel, so have a look and maybe think about it. You have to add insulation in the empty spaces of walls and ceilings too, but it all works together.
Cheers, Tom.

Resiliant channel is more designed for stopping noise. Its affects on the acoustics in the room are unpredictable at best. You may obliterate bass performance inside your theater room.

Really?

I can't completely agree with this. Yes, resilient channel is for soundproofing. It has been pretty thoroughly studied, and will attenuate sound by as much as 10 STC points, depending on construction details. However, it has little effect on frequencies below around 100 Hz.

Wall and ceiling acoustic characteristics are quite variable in these low frequencies, regardless of construction details. This is because wall and ceiling structures resonanate at between around 50-100 Hz. Such resonances may positively or negatively affect room acoustics, depending on existing room modes.

Regards,
Terry

Well, I was just saying that it is designed from a "stopping noise" perspective, NOT an in-the-room acoustics perspective. If you do it right, I'm sure it can help your room sound, but I wouldn't go using it willy-nilly is all.