I've been experimenting and adding a few dbx components in order to improve dynamic range of cassette and vinyl playback.? Component include sub-harmonic synth (120X-DS and Dynamic Range Expander with Impact Restoration 3BX III).? However, I have have recently notice left channel distortion coming from the left DQ10 woofer, when played at a higher volume and with all dBx equipment bypassed.? The DQ10 pair has all original cross-over components.? I have confirm that this is not an amplifier issue by swapping channels.? I am trying to understand the failure mechanism when a speaker is blown.? Is it an over heated voice coil wiring where insulation simply melts off the coil, a voice coil that over extends normal excursion, or perhaps failure of a cross-over component?? Wondering if I can repair.? Playing back a 200 Hz tone at higher volume and lightly touching the cone, the distortion seem to be tamed.? The attached image shows a left and right channel distortion measurement with REW and a UMIK-2.? Above 400 Hz, it seems (at least to my hears) to play normally.? Would hated to replace the one original advent driver.? Suspect I would have to replace both.? Any suggestion for a good replacement if Woofer is beyond repair.? ??