John Sayers' Recording Studio Design Forum Archive

a few months ago I start building 11 rehearsal rooms and a recording studio in the same warehouse. the rehearsal rooms are finished and the studio isolation is next to finish, but there are some problems...

the rehearsal rooms are made by 20 cm concrete block sand filled and the studio first wall, idem. then the inner side of the studio is 40 mm 70kg/m3 rockwool and 15 mm sheetrock on steel framing with silent blocks.

yestarday while we're building the inner walls, a band were playing in the 3rd room. The studio is 4 concrete block with sand and the inner rockwool and sheet rock wall from this room. But, the sheetrock wall vibrates on low frecuencies and this vibrations run through the wall to the floating floor ( 40 mm 145kg/m3 rockwool + 60 mm concrete with steel mesh).

Perhaps this band were playing around 130 dB... but ... the studio isolation is next to finish.



Any question or advice??

some pics...

the second problem is what to do with the ceiling isolation... The person who are building sheetrock walls tell me is no necesary to isolate the ceiling because is made with concrete and 30 cm of foam bowel, and the inner ceiling with 40 mm of rock wool over it will be so enough.

this are the panels:

armstrong ULTIMA dB

http://www.armstrong.com/commceilingsna ... ineId=47.0



what about this??

Hugo, I'm thinking that you are having low end isolation problems with your wall because it has only one layer of drywall. This will give the wall a higher resonant frequency (not good). Also, one layer of drywall is not very much mass so it will vibrate fairly easily. If it's possible, I would try and add more mass/layers to that wall with 2, maybe even three more layers of drywall. I also suggest waiting for more replies to get more opinions.

Chris Yeazel

Hugo, you need to resize the image... It's 813 pixels wide, but the rules call for 700 pixels maximum.

what about deadsheet like this: http://portal.danosa.com/danosa/CMSServ ... g=2&site=4
between drywall layers??

is better two layers of drywall with deadsheet than 3 layers of drywall??

Hugo, as long as you've been a member here I would have hoped that you learned NOT to take the advice of people who have ONLY dealt with NON-acoustic construction; from your descriptions, I would say that it won't matter if you add TWELVE more layers of ANYTHING because your main problem is FLANKING sound at this point.

At nearly every turn, you've decided NOT to isolate (I do NOT mean INSULATE) parts of your construction that SHOULD have been - and now, you're surprised that you're hearing a 130 dB band in other rooms than the one they're playing in??!?

As I've suggested several times, you need to SLOW DOWN and LEARN before you build.

In the REFERENCE section, there is a large PDF document from our very helpful Canadian friends at the IRC - although it deals with WOOD construction, keep this in mind - concrete is an even BETTER sound conductor (for flanking noise) than WOOD, which was the main study of this document. Still, I think if you read through at least the summaries of

http://irc.nrc-cnrc.gc.ca/fulltext/rr103/rr103.pdf

it will clear up where most of your sound leakage problems are coming from.

Again, remember -

A gypsum wall installer is NOT an acoustician.
A framing carpenter is NOT an acoustician.
A Concrete contractor is NOT an acoustician.
A Painter is NOT an acoustician.
A Brick layer is NOT an acoustician.

So if you're going to take ALL those people's advice about soundproofing and acoustics, WHY DO YOU EVEN BOTHER COMING HERE?

If I sound just a bit irritated, it's because I AM - the MAIN reason I do this at all is so that OTHERS don't have to endure the ANGUISH I went through after finding out 20+ years ago that the rooms I THOUGHT I was building were NOT EVEN CLOSE to being as soundproof as I'd intended. So, when I have to read about people who've ALREADY BUILT and THEN ask for advice, it causes me MORE anguish, which is painful enough when that person DIDN'T KNOW BETTER and just found this (or other) forum.

But when I have to explain these things AFTER construction to someone I've already advised to SLOW DOWN AND LEARN MORE, it gets REALLY frustrating.

I'm sorry I'm sounding so mean and cranky here, but I'm 60 years old and only have so much energy (it's never enough) - so I hate to waste it on people who WON'T LISTEN... Steve

Would have picked you for mid thirties Steve!!

Thanks John, but it's just my immature personality

Perhaps I was in a hurry...
So, there is no solution?? No mass could help to isolate the low frecuencies...???

Soon I'll restart the studio contruction . . .

But, how can I have flanking sound problems if I have 1 block wall and steel framing with silent blocks (rubber pads), there is no contact with the flanking walls...

Hugo, sorry I got so testy; been a madhouse around here so I was already irritated and probably shouldn't have answered at all at that time.

cyeazel may have found at least PART of your problem - remember, the basic theory of isolation is mass, air, mass - the more of each, the better. If you only have ONE layer of gypsum on your iso blocks, it's not enough for decent isolation especially at LOW frequencies.

If making a sketch of exactly how your construction is done is too difficult, maybe you can just review the parts in REFERENCE section about inner mass leaves NOT touching outer mass leaves other than through isolators (like neoprene, RSIC's, RC, etc) - and if all that is done right, make sure all SEALS are good; after that, adding more mass should help. In your case, you'll probably need THREE layers of 15mm drywall (review the rules about staggering seams, seals, mudding, etc) before you kill that 130 dB band enough to be usable... Steve

maybe this draw helps...

when I put my ear in the sheetrock layer, I can hear low frecuencies (bass and drums an a bit of distorted guitars...).

the rehearsal room next to the studio is mine, no problem with music in this room, but the next is used by a metal band.

So, 3 layers on the bottom wall and 2 on the lateral wall may help on low frec isolation??

Yeah hi!

I'm doing something similar, but everything is controlled by an acoustics expert. When interviewing builders i had so many people telling me many false facts about this technique. Rules are rules, i suggest you read this whole forum back to front and as many books as possible before making similar mistakes.

As far as i know it is the layers of different matirials that mostly absorbs the sounds at different frequencies which have to be carefully selected by experts with a proven concept. You can see how many layers are required. Cutting corners saves money but in the long run if it doesn't work, what's the point?

This is my technique garaunteed, it's in German.