can i treat a room thats 1/2 BRICK 1/2 SHEETROCK?

i found a large room with good dimensions that im thinking of using for a mastering room. the problem is that the room front and left walls are BRICK, and the right and back walls are Sheetrock. can i still treat the first reflections with absorption on the front half of the room? or will i need to build Sheetrock walls over the concrete to make it all the same surface? any info on this is really appreciated. thanks

I would say that it depends on what type of mastering you are planning. If it is a high-end mastering suite, meant for serious professional mastering of movie sound-tracks, commercial music for well-known artists, and suchlike, then I would at least get the two side walls similar, but if it is more of a hobby or mid-range mastering setup, them you are probably OK leaving it like it is. But in either case, a mastering studio will need far, far more treatment than just "treat the first reflections with absorption": Mastering studios need to be accurate, neutral, precise, and carefully tuned. Even a low-end mastering room needs substantial treatment to make it usable. The entire room needs to be very carefully designed, laid out, and treated. In all aspects. The goal is to meet or exceed the specifications published by the AES, IBU, ITU, and others, which define the acoustic response that is necessary in such a room. If you are aiming for a high-end professional room, then I would indeed try to get the two side walls behaving similarly. You could do that by either adding more rigid mass to both sides, probably with a couple of layers thick fiber-cement board, then base the actual acoustic design of the room within that new shell. You don't need to worry about the front and back wall being different: that's not a problem. However, a high-end mastering room usually also needs to be extremely quiet, something like NC-15 or even better, so I would start out by ensuring that you have enough isolation to get to that level, which probably implies doing something to all of the walls and the ceiling too, to increase isolation. - Stuart -

Stuart, thank you VERY much for your reply. it was extremely helpful. i completely understand. thanks