Something I'm a little confused about. \n\nI followed HTG MiniDSP tutorial as he said. Mainly, the idea that level matching the subs to 75db is what throws me off. Starting, I set the sub gain in the AVR itself to 0, turned Audyessy off, and then to start calibrating with REW he says to adjust the volume with the main AVR volume to 75db on the SPL meter in REW, and then start your sweeps to calibrate with REW.\n\nI did that, everything went as it should. But my room is 16x24. I like to listen to my movies loud. I recently build 2 18" LaVoce Marty's with an NX6000D. I went thru the calibration, but when I turned it up unknowingly at that point, at high volumes it reached a point where I'm guessing it was input clipping, or perhaps even just reaching a point of distortion it made a awful sound in the woofer itself. I thought they were blown or ruined. I really had no idea. \n\nI unhooked the DSP and went straight to Audyessey, loaded my old calibration, and the noise went away at high volumes. Hooked the DSP back up, the noise came back. I started reading a bit and noticed people talking about input clipping, so I started lowering the gain in the AVR itself.. Went to -8, turned up the gain on the amp and in the miniDSP software - I can now play at any volume I want, turn the subs up to any level I want and the noise is gone. \n\nWhat causes what I'm guessing, is the input's clipping? Is it not enough voltage in the signal? Just a point where is distorts?