When using the auto calibration in an AVR, if you run it, and it turns the line level to the sub up or down a tad, (i.e. +.5db, -2db, etc.), wouldn't it make sense to just adjust the level of your sub to reach zero on the auto cal?
I mean, most AVRs suggest running auto-cal with the sub at 12 or 1 o'clock, but that level is going to be slightly different on every sub. So wouldn't the ideal thing to do be to adjust the sub level to meet 0 on the auto cal, rather than having the AVR adjust the signal? That way, the sub is receiving more of a reference line level, and the sub's amp is doing the work instead of the AVR preamp.