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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
vegasears
1,173 posts
 
rumble

http://en.wikipedia.org/wiki/Rumble_measurement
snofun3
601 posts
 
Check phase
swampwalker's avatar
swampwalker
5,138 posts
 
Could also be DC at your amp output.
madfloyd OP
411 posts
 
Check phase: you mean speaker phase? This is correct.

DC at amp output: can you explain this?

I probably should have mentioned that I'm using a Triplanar/Dynavector XV-1s.

Read up on the rumble and it does describe my situation. How normal is this? Is there something that can be done or does one just live with it?
dlcockrum's avatar
dlcockrum
2,190 posts
 
The cause of this problem is most likely very simple. Is the woofer pumping worse at the beginning of the record and then lessens as the tonearm moves toward the center of the LP. If so, the outer edge of the LP is probably not coupling with your platter. You may even be able to see light between the outer edge of the record and the platter when viewed on-plane from the front.

If you are using a clamp, try lessening the downward clamping pressure to see if that helps. If it is a problem with LP/Platter coupling, the best solution is a peripheral ring (like the one sold by TTweights and others), but some say that these rings deaden the sound as well. I don't have one so I don't personally know about that.

If the pumping occurs across the entire LP, then Cpk likely has indentified the cause(s) above.

Good luck.
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