room in room contruction neccesary?

Hello all, i'm still in the design/material/ cost calculation phase for my mix/control room and booth. the mix room size is 10.6x14.7x8.2. walls front and back of the room bordering on the neighbors are concrete, right wall is glass, left wall is Ytong blocks. floor and ceiling are concrete. i'm thinking to do a room in a room construction. but the space is already small so i rather not do it if not absolutely necessary. other option is to do just the walls that need extra mass and seal that off properly. i cant see how adding a leaf of gypsum/studs construction would add anything to a 1 ft thick concrete wall, and ceiling. if at all effective i would just treat the 2 walls that have less mass. is this an effective approach or is my way of thinking incorrect? thanks! J.

generally speaking, the concrete walls will conduct sound very efficiently into your neighbors space. you might want to do some tests to determine how much is making it through. using a rubber mallet and a metal hammer, have someone tap the wall and floor in various spots while you make notes on the sound coming through from your neighbors place. also, if you have a stereo or PA capable of playing something with a lot of bass and drums (or pink noise) loudly, you can take some measurements all around using an inexpensive sound level meter. this will give you some idea on how much sound is escaping your room and from there you can determine how much isolation you need and what it will take...

i will do that to determine whats needed. if not much sound travels through( and i suspect it wont, i know the building and not much sound travels to the neighbors) is it possible to only build another leaf along the walls that need it, or if i do anything i have to go with a full room in a room construction? thanks! jaye

in my opinion, if you don't have much transfer, then you may be able to get away with adding the single leaf or even just treatment walls (like John's inside-out walls). you would then concentrate on windows, doors, etc. to keep sound from getting outside or upstairs (if you need it).

uuummmmmmm........... that's actually where it gets pretty hairy......... checking things out with a SLM is one thing - determining where the sound is coming through is another thing altogether......... for example - assuming for a moment that the walls aren't your weak point - then adding 10 layers of mass to them is not going to add anything to your isolation. Determining what levels are making it through is a good start - but if you really want to know how it's making it through - then you should hire an acoustician in your area for a couple of hours to check things out for you...... it's foolish to just make assumptions based on measurements that can never tell you the path the sound is taking. Sincerely, Rod

thanks, @ Rod, i don't think theres any leakage anywhere, the building is contained within its own concrete walls however that wall is shared with the neighbors. the floors are not attached to the neighbors floors in any way, its a different slab. so is the ceiling. i do think it touches the 1 foot concrete steel reinforced wall that i share with the neighbors though.i noticed theres practically no leakage through the walls. any leakage there is comes through the weakest part of the construction, the prefab window construction. Apart form hiring an acoustician, is it worth it to only deal with the weakest walls i.e. the prefab window/wall construction and the wall build of ytong blocks? i know for sure they leaking. Or would you say to to be on the save side do a full room in a room construction anyway?

Listen - I agree right now that the windows / doors are probably your weakest links - but you might find little difference if you close them up - HOWEVER - make your window and door openings equal to (or better than) your walls and floors and then check it out - even if it doesn't get the whole job done - you would have had to do it anyway as a part of the room withing a room.......... and then you will know what your next target level is................ if anything....... Rod

right.. I'm gonna take that approach and then do some tests to see if what i ended up with is acceptable, if not i 'll just do the rest. i probably still get an acoustician in to see what he thinks. thanks!