Do you have the Onkyo set so that right and left speakers are "large", if so set them to medium or small (not sure what might be available)This would be the first thing to check.
Type: Cerwin-Vega CLSC-15S
Reciever Onkyo TX-SR800
Problem: I just purchased this subwoofer and installed into my system but I'm not getting the "jawdropping" thump I expected. I'm hooked-up through my LFE pre-amp sub output on the Onkyo and have it turned on through my menu settings for the speaker config. The speaker test works fine for the sub but during regular playback I can barely notice the bass. I can turn the volume up on the sub but then it makes a real bad humming noise. This is my first atempt at introducing a sub to my system so I'm there is some tweaking that can be done. Any suggestions? Thanks

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