I'm renting an apartment (should I post in that forum instead?) that has a 7'x8' room in the basement that is cinderblock and earth on three sides. I'd like to turn it into a place that I can play my trombone without waking anyone sleeping upstairs, ideally for about $500. Already, with no acoustical treatment, I have a 30dB decrease in volume from that room to the floor above. However, there are hvac ducts and whatnot that do carry the sound up, and it's not quite quiet enough for someone to sleep through it.
Because three walls and the concrete floor have enough mass that they really transmit no sound whatsoever, I'm not worried too much about isolation in the walls. If some sound escapes to the rest of the basement, that's not a problem. It's only sound traveling up that I'm worried about.
My current plan to soundproof the ceiling involves 2 layers of 1/2" drywall sandwiching green glue, suspended from genie clips. However, I'm going to have to invest a fair percentage of my budget in ventilation and moisture control to keep that basement room dry and sanitary. So, I'm a little overbudget, and I'm wondering if there are any obvious ways to minimize costs.
Are there things I can do that I have not considered that will improve my acoustical isolation? Is it better to cut the green glue or the clips? What are your opinions?