Are you a computer guy
you mean hZ(hertz) not mhz
On my Axiom sub, there is a volume control and a crossover control. I have the volume set around 11'o clock position. I believe the crossover on the sub is for if you had a receiver that does not have crossover managment. I'm sure some of the others will chime in here if I'm wrong, but if you have the receiver set to small on all speakers, with a crossover of 80hz, then any frequency for all of the speakers below 80hz will be sent to the sub. You want to turn the sub crossover all the way up, or clockwise to its highest setting so the receiver and sub are not both trying to manage.
However, you say you have the mains set to large, so in that case your mains and sub are getting all of the low frequencies, and the crossover is only sending the stuff below 80hz for your other speakers, to the sub (center, surrounds)
I'm confused on why the bass would get louder if you turned the sub crossover up to 150 or whatever the highest point is, maybe someone else will help out....
