soundproofing a warehouse
Two businesses in an all brick building under one roof share a back utility room (gas, water, and electric meters.) One of the businesses is a store front church, when in session, they have an amplified band and 50 perishers singing. They open up their back door, (and refuse to close it,) to allow air circulation into their space. While in our adjacent warehouse (a film production studio) with our back doors closed, their sound still travels into our space preventing us from recording. We are looking for solutions. We've already tried hanging heavy duvetyn on the back side of our door. This doesn't help at all. Now we are looking at installing a second set of doors, air tight, with an 8 inch air gap in between the two sets of doors. This could run a few thousand dollars, but I don't know if this will be worth the cost, and also if the sound will also be traveling through the brick wall or find another way in. The brick wall is 14" thick. Any suggestions? Thanks.