My audio friend Eirik came around today and helped me tighten the housing of the spindle on the Hanss player. Luckily the needed 2.5 mm Umbraco driver was included in the set I had bought. So - what was the result? Pumping: no difference. It did not go away. Sound: maybe a tiny bit more relaxed, less tense, but this may be my imagination. Eirik brought along some fine-sounding records and we played tracks from the Mofi edition of Dylan's Another side, and from the reissued Grateful Dead Cornell 1977 box. They sounded very good, and neither he nor I could find any clear indication of too much rumble. But he did remark on the LOOKS - the visual (subsonic) pumping of the woofers especially between tracks. It does not look like that in my system, he said.
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?
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- 185 posts total
Dear @o_holter : Two question, how is conformed your system speakers and its frequency response? is a passive design or active? two subwoofers or none? well more than 2 questions and other one. I posted before that could be a good test to try to borrows a full SS phonolinepreamp instead buklbs you are using. I think you have to have that test, is a must. R. |
Dear Raul, thanks! 1) The speaker system is Audiokinesis, Dream Makers in front, plus LCS speakers firing towards the roof, in the back of the fronts. Similar to this one (but in much nicer light wood):http://www.audiokinesis.com/dream-maker-lcs.htmlThe frequency response is down to 20hz or lower in the combined system, not sure. It goes deep, that's sure. But if speaker energy into the room etc was the main culprit, I would NOT have woofer pumping on my vinyl recordings (made when the speakers were off) - and I have! 2 Borrow full SS phono pre - yes, good idea. But again, I wonder, if this would solve the mystery. If it was related to the phono pre, the pumping should appear, depending on the volume. But it doesn't. It only appears when the needle is in the groove. More or less, depending on the vinyl record. Usually - maybe always - in EXACT repeat, each turn of the record. The pumping pattern seems to follow its own logic, different from the normal vibrations and excitations of the woofer. As stated above, it is less obvious within than between tracks. This evidence suggests that it does indeed relate to the cart - arm match - it has too low resonance, and picks up too much down-below vinyl excitations, for some tastes, or just "good enough" for other tastes. The whole system goes deep down. We played Pink Floyd: Meddle, the intro number, with the hammering bass, and noticed that a bit of pumping was still there, but NOT in time with the bass notes, but repeating - like before - in a once per revolution pattern. |
"The highlighted noise on the LP playback, approximately 7 Hz, is absent on the CD. By
the way, the very low frequency noise was present on every LP I played
for this test: from new pristine vinyl to older worn LPs with more
clicks and crackles." https://www.vinylengine.com/turntable_forum/viewtopic.php?f=18&t=99388 |
- 185 posts total