Admittedly, I've NEVER calibrated my sub. BAD, BAD HT BUFF! I know. So...I'm trying now. I've used the Avia disc and done the best I can, but I seem to have a big hole in my low freq. sweep between 140-150Hz and 100-90Hz. I've got a JBL SCS300 5.1 speaker set up (5 small satellites) running on a Sony 444ES receiver. The JBL sub has a "volume" knob only, which has been calibrated to be in line with the five other channels using the SPL meter. The receiver does allow me to set frequencies on all 5 channels. All 5 seem to indicate the same holes. All speakers are currently set to "small" and the frequencies on the sub are currently at 100Hz. I don't even know where to begin addressing this problem. Is it in the cutover settings on the receiver? The volume on the sub? Any insight would be great! I feel so stupid...I've always picked up this calibration stuff on the first try. This sub stuff is really stumping me! The search function on this forum hasn't been working for a couple hours...so I apologize in advance because I KNOW this question has been asked before.