Help with ringing bass from Dynaudio C1

what are the speakers standing on? if they have feet or footers, tighten them (or remove them if the footers are on a platform); are the screws lose which hold the driver?

They are on Core speaker stands. I tried picking up the speakers and holding them while they were ringing; it made no difference.

The driver screws are tight.

Having owned the C1 and now the C1 Signature I have never heard of that problem. Does it happen with both speakers? Does it happen only at high listening levels? I've driven mine with a Bryston B100 and now an Octave V70Se. I've heard C1's with Naim - Sim Audio and Burmester. Since the speakers are passive I would think it is something upstream. Try without the conditioner. Any possibility of borrowing a different amp? Another option may be to bring the speakers to a friend or dealer and listen to the same passages but on a different system.

That being said I have overdriven mine to where the woofers bottomed out. But that sounded more like someone hitting the cabinet with a padded baseball bat. But it didn't ring or last past the low note.

You'd think if your silverlines were ok then it's got to be the speakers and there is something wrong, they are broken. There is no way this speaker just does this if it is such an obvious flaw. Hopefully you bought them new and can get warranty service done.

Having heard these speakers more times than I can count Id say there is an issue w/C1s.If your running the system in the same room with other speakers and you dont hear the problem,,its your Dynaudios as this is most certainly not common