i want to know about limiter function, what dose it work for? what's difference between limiter on and off? i'm using tascam DR 40, i was spoiled my ourdoor live concert recording , the sound was distorted especially base drum part except other parts were very clear, setting was dual rec, dual LVL i don't know how to set it up, dual LVL is raging from 0- -12db, should i off or setting at -12db, and is there mics gain control on tascam DR40 ,please give me your tips for best sound setting