While tuning my sub/speakers setup, I heard a gap between base and mid-range. Adire Rava sub was crossed at 80 Hz to match my Nakamichi AV-10 receiver crossover point while listening to stereo. B&W 602 S3 speakers were set to small. The gap disappeared and base "connected" to the rest of the frequencies when I notched up the sub to 100Hz - the problem is that base lost a bit of accuracy. Does anyone hava any idea why speakers and sub don't blend in at 80 Hz? Nakamichi AV-10 is a reveiver. BTW, lower freq/ cut-off used in sub - absolutely hated "Full" setting on Rava.