Question about doors and drywall

-Location is Chicago and I am in the framing stages of this studio. -Room dimensions are approx, CR=15x12, LR=21x11, VB=9x4 and the overall average height is 10.5 ft -There is no one above me and it is located on a concrete slab. The exterior walls are 2 layers of common brick and there are no neighbors for at least 100 yds in any direction -Most of clients will be rock or jazz groups -My question is about doors. My budget for doors is around $1500. In the print below you see separating the control room and the live room 2 sliding glass doors, this is no longer so. I am going to go with a standard 36" door doubled. The same is going to be done for the vocal booth. What I want to know is can I use exterior steel doors with a foam core and a full length thermopane glass to achieve a good STC rating? These doors are prehung and come with very good weather stripping. They are basically off of the shelf from Home Depot. -Also I've read that 2 layers of 5/8" drywall is ideal and also I've seen to use 5/8" and 1/2" to kill different frequencies. Which is best?

Egg, My lurking here and reading of Rod's book lead me to believe the thermopane windows (2 panels with gas between) are not the best for isolation because they effectively set up a multi-leaf system. I have also ditched the sliding door concept in my design. I plan on using the super door concept (one really heavy door instead of two) described in Rod Gervais's book(check the stickies..). I will probably create a window in the door by installing my own single pane (thick) glass into it. I'm afraid quick and easy solutions are a bit hard to come by here..... Regards, Mark

Sliders main benefit is visual - and it's getting harder (in this country, anyway) to find anything BUT a double-pane glass, either slider or other windows; so you will almost always end up with a multi-leaf configuration going that way. One option MIGHT be having a local glass outfit custom glaze your choice of frames with heavy SINGLE pane glass, and make two such units for each doorway - an expensive option for sure. As to the different thickness vs. two 5/8 - while it's true that a layer of 1/2 and a layer of 5/8 will slightly improve (lessen) the coincidence dip in a wall, this is typically a frequency in the range of 2-3 kHz; for music isolation, the low frequencies are the hardest to contain and the solution is MASS. For this reason, both Rod and myself have come to the conclusion that double 5/8 is as good or better for this purpose than using separate thicknesses - plus, it's less confusing on the job site than trying to find room for separate stacks of drywall AND remembering which to use next... Steve