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Why are my woofers pumping?

The other day, with sunlight direct from the side, I noticed that the woofers in my speakers are pumping in and out, much more than I was aware of, when the stylus is in the groove, even between tracks (no music).  I can see it, even if I don’t hear it. Why does it happen? The woofers behave normally (no pumping) with digital music, and when the stylus it lifted from the groove, so it is not the speakers, amps, preamp or phono stage. 

I’ve read that the typical reason for woofer pumping is that the cartridge / arm resonance is too low.  I tested, with my Hifi News test record, and yes, the lateral test puts the resonance at 7 hz or so – too low (but I’ve seen some doubts about the results from that test record).  It is strange, since the combo I use – Lyra Atlas cartridge and  SME V arm (on a Hanss T-30 player) is supposed to work well. I tried to strip my arm of extras, cleaned the damping trough, etc – but it did not help much.

Anyone has an idea, why it happens, or what to do about it?  


o_holter

Showing 2 responses by krelldog

krelldog
323 posts
 
I've had that same issue. I bought the rumble filter....it degraded the sound and didn't cure the problem either.
I actually had a post on these forums and someone recommended moving the turntable away from the speakers.
I moved my speakers out into the room as much as I could and the problem was solved. I now rarely get this to happen....and when it does I lower the volume a couple notches and it goes away.
I'm convinced that if I could move the turntable completely away from my my speakers...there would be no issues.
The issue is with your cartridge and speakers. That's my opinion.
krelldog
323 posts
 
I think it was the KAB filter....or something similar to that.

I'm not saying its not a good product....it just didn't work for me.
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