New Member Lost my Bass in Speakers...HELP

[singring]

I have a pair of Koss CM1030 speakers, and they have worked great for many years. While playing some vinyl yesterday, I selected a filter button on my Carver preamp, that send a loud low tone to the speakers, extending the woofer cones out. I immediatley selected the filter button again, the tone stopped, the woofer cones relaxed inwards, and there was a bit of a pop sound. I have opened the preamp, did some switch cleaning, and now the preamp is fine, but I have lost a lot of bass response from my speakers. The punch is gone; the air ports used to blast air out, now there is no air movement. When i first connected the preamp to the amp, I immediately noticed the total lack of bass unless I turn up the tone bass tone control knobs and select the loudness button. I then tried an old spare amplifier that also had tone and bass controls, and a loudness button, just like my Carver preamp. I turned the bass on at full and in with the loudness button. Now the bass appeared, but a bit under what I would call a normal level, and it also muddies the overall sound. The issue is with the speakers, as the loss of bass happens with both amps.

What can I do to test the woofer voice coils? I already did a movement test with a 1.5v battery on the speaker cabinet inputs, and the cones move out, and in when I reverse the battery terminals. There is no scratching noises when I gently push the cones into the cabinet.
Any adivce is appreciated. Thanks

[mashaffer]

May have damaged something in the electronics or the speaker crossover. Measure the voice coil resistance (disconnected from the crossover). It should be slightly less than the nominal impedance of the driver. If it looks good hook up to another amp and see if they do any better.

If no other amp is available try a different set of speakers on this system after checking to be sure there is no significant DC on the speaker outputs.