Woofers getting workout, but no bass


I'm puzzled: I'm noticing just about every LP I've played in the past couple days has my 10" woofers moving like mad, but not in time with the music and regardless of whether there's any audible bass.

I can only conclude that I have subsonic frequencies occuring (my phono stage doesn't have a filter). What would cause this?

Relevant components:
Speakers: Wilson Sophia 2's
Turtable: TW Acustic Raven One
Phono stage: Tron Seven

Thanks in advance.
madfloyd
YEs, changing cartridges may have an effect but I am not certain how to determine what to switch to to assure desired results. Higher compliance maybe? Something that produces a different resonant frequency with the specific tonearm utilized perhaps?

PErsonally, I am not a fan of filters of any type. With proper setup and match of equipment, the problem is usually not an audible issue to start with. GEtting to that is the trick of course though. Record players can be tricky beasts and not easy to get right!
One thing you might try is to put a gram or two of something like blu-tack on your headshell and a corresponding amount on the counterweight so that your VTF remains the same.

This will change the effective mass of your arm and the resonate frequency of the arm cartridge.

It may or may not work but it is cheap and simple to try.

Regards,
Todd
Here's more background info on cartridge compliance, resonance frequency, and potential impact for rumble, etc.

http://www.gcaudio.com/resources/howtos/tonearmcartridge.html

Hope this helps.
Madfloyd,

I am considering buying a TTweights peripheral ring, so I would greatly appreciate your feedback on whether it reduced/eliminates the woofer pumping and also you perception on its effect on sound quality.

Although the woofer pumping generates frequencies that are (mostly) too low to hear directly (unless the woofers are bottoming out), it does load your room with low frequency pressure that will affect the sound (ala REL sub, but in an uncontrolled way).
I have some records that are worse than others when rumble is observed via cone excursion. Same cartridge. Concrete floor...shelves made with carbon fiber/epoxy 1/2 inch thick. The Navy uses this material on bulkheads to minimize internal shrapnel from external explosions. No clamp or other weighted object reduce rumble in my case. Probably in most cases.