Are you sure the GC knows anything about acoustic treatment vs. soundproofing? The former is to improve the quality of sound inside the space and the latter is to keep it from getting out of the space. Not at all the same.
For info, take a look at:
www.rivesaudio.com
www.realtraps.com
Kal
For info, take a look at:
www.rivesaudio.com
www.realtraps.com
Kal