in my experience, they sound roughly the same (quality wise).... some will argue, but test it for yourself. compare a track off beatport(320kbps mp3) and a track from itunes (256kbps aac), but generally any track is only as good as it's production. but in answer to your original question, I rip all my albums at 192kbps and have zero problems playing them at house partys of 50+ people The lowest I have played on a bigger sound system at a venue is 256kbps (mp3), but generally I would only opt to use 320kbps whilst playing out. hope that makes sense