I have a customer that asked that I place 5/8″ sheetrock on walls opposite of walls with 1/2″ sheetrock in the same room because of the resonance. He belives that having the same thicknesses on opposite wall will cause sounds to resonant and increase the noise level in the room. He is paying the bill so he gets what he wants. I would like to know if there is any truth to this?
Thank you,
Ash
Ash
Replies
i know this works on glass but never heard of it on rock. i think there is more effective ways of controling sound.larry
Sounds logical. Different thickness of the same material resonates at different frequencies.
Is he concerned about low frequency transmission?
Don't know about the sound transmission, but since he is paying the bill, and there seems no argument agianst it.....
Be sure to point aout the addtional cost of that 1/8" in wall thickness, in terms of jamb extensions. Not an issue for split jamb doors, but a standard rabbeted jamb is going to be under sized for the wall thickness. Also be sure to tell the electrician, so he can set the boxes out to match the wallboard thickness on each side.
Dave
Well, then, it's time to tell your client about the "wellness hotels" you encounter in Europe, particularly in Switzerland and Austria, where a master wall switch in each room, next to the door, is used each night at bedtime, to disconnect all the wiring.
Allegedly, one sleeps better without being surrounded by hot electrical wiring.
Most hotels in Europe I've stayed in have a master light switch by the bed that turns off all the room lights. I find it very convenient. The switch didn't disconnect the outlets (my phone still charged), just turned out the lights.
Leigh
I have heard of this done on opposite sides of a framed stud wall to reduce sound transmission. The 1/2" rock filters certain frequencies and the 5/8" rock filters different frequencies, and you are less likely to get resonance inside the wall cavity.
I have never heard of it being done on opposite walls -- I doubt that it will work very well for sound reflected off the walls versus sound transmitted through the walls.
Billy
That is the basic theory behind soundproofing a room with two walls really close together and useing different thicknesses of DW to cover them. It works to a lesser extent on one wall, but there is still some sound directly transmitted through the studs.
It reduces the coupling of the two walls wich further reduces transmitted sound. Also, since the walls vibrate at two different frequencies, they won't resonate and that keeps sound between them at a minimum.
If the sound between them is lessened, the sound transmitted out side is lessened.
If you want to make some more money, explain to the client that If he were to use different thickness on the outside or other side of those walls, he will get better results, due to no resonances in the wall cavities.
If you're also doing the framing, one wall should be 2x4 and the other 2x6.
SamT
In theory there's some truth to it, and, given the (low) relative cost difference, it may not be a bad idea.
How much difference there is in practice is hard to say, and would depend on a lot of variables -- humidity, fastening technique, stud spacing, etc.
In college I worked with some guys at Wright-Patterson AFB who measured the vibrations in a "skin-stringer structure" (the aircraft equivalent to a stud wall with rock on one side). They found that the tightness of the rivets made a lot of difference in the resonance of the structure.
(It actually would be a fairly cheap/easy thing to test, if someone has access to some sort of sound studio or lab. Would be a good article for a grad student, if anyone knows someone in that position.)
Actually, on re-reading your post I see he's taking about opposite walls, vs opposite sides of the same wall. I'd be more inclined to try it on opposite sides of the same wall, to reduce sound transmission. Transmission depends a lot more on the flex/resonance of the material than does reflection.
Of course, on opposite walls it's still in the "can't hurt/might help" category.
Tell them that a pyramid shaped hat made from aluminum foil does the same thing
;-P
It seems like he thinks too much. But, he's paying the bill, no harm in doing it the way he wants.
Cater to his comfort level without comment. He needs to feel comfortable in his enviorment. There's no point in knowing more about it than he does!
blue
Warning! Be cautious when taking any advice from me. Although I have a lifetime of framing experience, some of it is viewed as boogerin and not consistent with views of those who prefer to overbuild everything...including their own egos
Additionally, don't take any political advice from me. I'm just a parrot for the Republican talking points. I get all my news from Rush Limbaugh and Fox and Friends (they are funny...try them out)!