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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?  


Ag insider logo xs@2xo_holter
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o_holter OP
977 posts
 
More surprises: Simple Minds: New gold dream, 2016 half speed remaster - pumping - yes. Procol Harum: Home, UK orig - some.

Thanks vpi. This is my thinking as well. I will first try a different cart, and then maybe, a filter, if I get a money back option. A significant fact in all my investigations so far, is that "pumping" LPs are often very good sounding. Lean back and enjoy it.

Raul - yes, I have a somewhat worn Clavis is on my loft. I could test it. But I think the compliance is similar to the Atlas so the test may not tell much. Let me tell you, I don’t like exchanging cartridges....do I get my former adjustments back...or do I have to start from scratch, for cart adjustments.
invictus005
597 posts
 
This has to be the most ridiculous thread on Audiogon at the moment. Everything and all of it. OP, I told you it’s a problem YOU can’t solve. Just enjoy the music. Some of these things are just part of vinyl. Many comments here have crossed the line of insanity. Seems like some people want to end up in a mental hospital?
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o_holter OP
977 posts
 
Invictus005 please. What may be ridiculous to you may not be so, for fellow a-gon members. You seem to "know" it all - but where is your actual listening evidence? We're all in this hospital together.
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rauliruegas
13,101 posts
 
Dear @o_holter : """   compliance is similar to the Atlas so the test may not tell much........ """"

well, you have a " problem " that till today you don't know exactly the reason or reasons for it. You assumed that cartridge/tonearm resonance is the culprit but you really don't know because you just don't want to make tests as listen the same system with different cartridges ( Clavis DC. ) or with different tonearm that you can borrow from somewhere or some one.

Clavis has same compliance: so what? from where came that can't tell you nalmost nothing?

makes no sense that kind of answers from you because you need to find out ( or maybe not. ) what's happening making different kind of tests and if you don't want to do it then is better to just forgeret about as invictus005 said and try to enjoy MUSIC.

R.
audiotomb's avatar
audiotomb
1,112 posts
 

one thing to try

play a record Try to move your tonearm on the record sideways with a light feather

if the tone arm doesn’t move sideways
chances are the bearing in the tone arm is rigid causing It to not move correctly

if the bearing is locked up
all the up down motion of the cartridge to the record is occurring via the cantilever not the arm bearing

the cantilever going up and down produces woofer pumping



Best wishes
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