BTW, really in that large room, I'd be covering the concrete walls with 2x4" framing with drywall to help soften the sound. The hard walls will make your sound, well hard! Good for Viagra, not your sound system. You need balance here, not unyielding sound.
The blance of reverb should still be good, with the cement walls directly behind also. Then, just do some diffusion pannels around the room, on sides/front. This will be all you'll need trust me. You should be good to go acoustically...no large bare wall surfaces for you on front/sides!!!
The blance of reverb should still be good, with the cement walls directly behind also. Then, just do some diffusion pannels around the room, on sides/front. This will be all you'll need trust me. You should be good to go acoustically...no large bare wall surfaces for you on front/sides!!!