Woofer sucking in and out

I have a problem with my analogue set up that once it starts play, the woofers of my speaker will move in and out like crazy, unrelated to the music! It relates with volume as when the volume is low, the woofers will not move as much. May it has to do with oscillation between cartridge and arm but my set up is new. The turntable is Acoustic Solid-Transparent and rega301 arm with cardas wiring and weight mods, Herron VTSP 3A pre and VTPH phono. I wonder if placement has anything to do with it or power connection.
I hope someone who has the same problem before can give me some hints.
Hi Luna,

As Ralph (Atmasphere) said, you should make sure that the arm/cartridge relationship is correct. If there is a mis-match between the resonant frequency of the arm and cartridge it will cause very low frquency problems which will translate into pumping woofers.

If your analog set up is new you may want to contact the dealer that put it together for you for assistance. Brooks Berdan is widely considered to be an analog expert.



Absolutely the arm/cartridge relationship needs to be correct. But if you read the post from the OP.

"I have moved my TT to another spot at the back with some success. The movement is not as big as before."

With no other changes to cartridge/arm. This indicates an isolation/vibration issue.
Hi Ct0517,

Thank you for your reply.

I did see that but I still feel the arm/cartride relationship needs to be examined again. Moving the TT probably only reduced the problem exhibited by that relationship.

The low freuency pumping of the woofers is probably not sourced from the speakers because it is much lower than their cutoff frequency. If it is sourced from some other source (like a large ac/heating system or a nearby industrial plant or highway) it can be verified by removing the belt from the platter and lowering the needle into the groove of a stationary record. If those are the source the pumping will be evident. The owner can also start the TT motor to see if that is the source coming up through the platter. If none of those are the source it is most likely an arm/cartridge mismatch or misalingnment.