STC of Johns room within a room constuction as per SAE

I have read and re read the SAE site, i am probably missing something simple, so i apologise if i have. I am trying to figure out what the reduction in volume would be if i were to follow Johns plans as per the SAE site, on building a room within a room. Building his panel type walls, seems like a great idea, as it takes care of sound reduction to the outside and acoustic control within the room in one foul swoop. Very nice stuff. So if i were to have say four brick walls (the exteroir walls of the building) and applied the room within a room concept as per the SAE site, and i had a drummer playing within the room very loudly, say 120db, what would you expect the outside volume to be? ( i realise we are gonna have to have a door there somewhere to let the poor drummer out...maybe... :wink: ) Also a second question. Does the STC rating mean that for example, if a method of construction is labeled as having say a STC of 50, that means that a source of 120 db, should in theory be reduced to 70 db on the other side? Third question. What is usually the annoyance level in db, for people within the house. For example you build a studio connected to a house, and its late at night, people are trying to sleep, what sort of level would be acceptable, is it for example 30db, 40 db, 20 db. Just so i can do some figuring of what to do or not do. thanks in advance Peter

Left bank is built with that system and outside the building you can just hear the low thud of the kick if you are within 6 feet of the building. cheers john

Thanks John Peter

John Sayers wrote:

Left bank is built with that system and outside the building you can just hear the low thud of the kick if you are within 6 feet of the building. cheers john

...And what can you hear in the Control Room? just curious... Thanks John.

about the same sen - maybe a bit louder :) cheers john