John Sayers' Recording Studio Design Forum Archive

Let's assume I build my walls & ceiling CORRECTLY with proper isolation...

Can anyone tell me what types of noise, sounds or sound-levels a double wall with an STC rating of 60-65 will block out?

For example, if I get an STC 60-65 rating on my double wall that seperates my live & control rooms, is it possible that a band can be playing in the live room, will I be able to hear them (or very faintly)?

Could I hold a conversation in the control while the band plays with no difficulty?

If someone is in the live room and goes up to the glass and speaks, will I NOT hear them? What if they yell? If so, that is WAY Cool!!!!

I'm just trying to gauge what to expect from my walls...

BradJacob wrote:Let's assume I build my walls & ceiling CORRECTLY with proper isolation...

Can anyone tell me what types of noise, sounds or sound-levels a double wall with an STC rating of 60-65 will block out?

For example, if I get an STC 60-65 rating on my double wall that seperates my live & control rooms, is it possible that a band can be playing in the live room, will I be able to hear them (or very faintly)?

Could I hold a conversation in the control while the band plays with no difficulty?

If someone is in the live room and goes up to the glass and speaks, will I NOT hear them? What if they yell? If so, that is WAY Cool!!!!

I'm just trying to gauge what to expect from my walls...

Addition to my post:

Also, could anyone tell me what STC Ratings pro-studios get from thier walls? And what STC rating should I be shooting for?

I think you won't like the answer in the short term. STC ratings are not important for studio applications. What is important is the low frequency transmission loss (TL). As great an explanation as any that I have of this in the excel spreadsheet found here (STC visual sheet), about three posts from the bottom of the page.

http://forum.studiotips.com/viewtopic.p ... sc&start=0

The sheet has lots of good information summarized and presented with graphs to illustrate.

If you are up to it, read the entire thread. Note it is two pages of threads.

Quite often studio designers will use a partition with a LOWER STC than similar ones of the same cost because the low end TL is much better.


To answer a couple of your questions, normal speech would not be heard through an STC 60-65 wall. Music, it is unknown. The above material will explain why.


Andre

Also remember that sound goes by the weakest link - to come close to matching the performance of your wall example, you'd need at least 1/2" and 5/8" glass (preferably laminated) spaced 10" apart - this would have better low frequency TL than a typical double layer double framed gypsum wall, but not as good up around 1 kHz, which is the coincidence region for glass.

Here is an example STC comparison with sound files - follow their directions for setup so you don't blow your speakers -

http://www.auralexuniversity.com/

And remember Andre's comments - two walls can have exactly the same STC rating, but since it's a single-number spec that has nothing to do with lower frequencies than 125 hZ, they can respond vastly different at lower frequencies (which are generally the most annoying to most people)

HTH... Steve

Semi related thread
http://www.recording.org/postt21117.html
RadioShack sound level meter shows 114db on one side of a double wall, and 55db on the other.

Saw that Bob, note that he use "A" weighting for the test - "C" weighting would have been more accurate for music... Steve