Have a '98 GS400 with Nakamichi. Found a factory 6ohm subwoofer at the local salvage yard, and plugged everything back in. Now spearker clips at anything above the smallest amount of bass. There's a functional relationship between the amount of bass, the location of the bass ****, and the volume of the radio, for when clipping occurs. It does just fine without any subwoofer hooked up, and is managable with the terrible aftermarket subwoofer, yet with the factory, for some music, I have to turn the bass **** all the way down... clipping gets that bad.

Bad sub-woofer? Bad amp? Thoughts? Thanks!

 

Most likely bad woofer. The coils can touch then not touch then touch. A trained woofer user (yes thats an official term LoL) can tell when the voice coil has been detached. If the coil is detached, but not completely, it can trigger the amp to 'clip' or rather, shut off due to a polarity cross. You can hook any random speaker to the leads and play bass and see if it still clips. If it doesnt, then you know for sure its the woofer. If it continues to clip, then its the amp. But I doubt that.