Why are my woofers pumping?

Han_n - yes I will test this more. The "low cut" option may be what I lack.
Toddc2 - thanks, I have followed up.

I mailed an audio tech the other day, is it likely my woofers are getting worn out? Even if I don't hear clear problems? Answer: after five years no - it is not likely.

Some more pumping and woofer cone vibration testing today.

Pattern confirmed: the misbehaviour is less than before, but still noticeable on very high volume. There is some subsonic pumping (I can see it but not hear it).

The interesting thing is: it happens at certain intervals per revolution of the record (playing silent grooves between tracks). If I turn up speed to 45, the pattern is repeated, only faster. This seems to indicate that player rumble or drive problems are NOT the main issue. The platter on the Hanss T-30 is perfectly levelled and revolves smoothly – the pitch is steady, there is no sign of imbalance or distress, and almost no perceptible vibration noise touching or stetoscoping the plinth.

So if the player is mainly fine, the answer must be that the cart/arm combo picks up “vinyl noise”. Please correct me if I am wrong!

Could this “inherent vinyl noise” be most strong down around the resonance frequency, at ca 7 herz?

I am investigating different filter options, with helpful answers from KAB and Satoni, thanks to your advice. Since I have invested in a balanced system (from the phono stage to the amps) I am not so keen to go back to single ended connections from the phono to the preamp, although this would be the easiest (and cheapest) way to know if I am on the right course – if a rumble filter would help.  

o_holter

Some more pumping and woofer cone vibration testing today ... still noticeable on very high volume. There is some subsonic pumping ... it happens at certain intervals per revolution of the record (playing silent grooves between tracks). If I turn up speed to 45, the pattern is repeated, only faster. This seems to indicate that player rumble or drive problems are NOT the main issue.

That actually sounds very much like a drive problem, such as a bearing issue or bad belt

.... Could this “inherent vinyl noise” be most strong down around the resonance frequency, at ca 7 herz?

I don't think what you're experiencing is “inherent vinyl noise.” I agree with @stringreen - it would be a good idea to start at square one and have Lyra check that cartridge. Did you buy it used? If so, it's immediately suspect, even if it isn't your only problem.

Before going on, I need to tighten the center shaft (with the magnets) to the plinth on my Hanss T-30. It is fastened by four screws from the underside of the plinth. Does anyone know the type and dimension? The screws are very hard to see unless the player is placed on the side. Thats a heavy and somewhat risky job, so when I do it, I need to have the right tool. The Hanss manual does not specify the type of screw, but they have confirmed that the shaft should sit tight. ("shaft" maybe not the correct term - I mean the cylinder that the spindle sits in.)

Tighten the center shaft - meaning: the housing of the spindle.

cleeds - thank you, yes I bought the Atlas new and it shows no obvious signs of wear so far.  You are right, it may be a spindle / bearing problem. So I want to eliminate this factor. I have a friend with a T-60 who may help me fix it, soon.

Resonance - a red herring? If so, reducing effective mass on the SME V may not be a good idea (+1 to Atmasphere, and others, for setting me on this track).

Therefore I thought, OK, let me go back to a normal setup of the arm. I screwed the upper bridge back on and adjusted the counterweight back so the spring weight does the job alone, tuning it to the 1.72g recommended for the Atlas. Then I checked, using the runout on R L Jones The evening..., on the same very high volume level as before. Did I see more subsonic cone movement / pumping? NO. Slightly more energy, touching the cones? MAYBE but not much. What strikes me is that the "tone" of the vinyl noise has gone down a bit, it reaches lower in frequency. (Usually a good sign, says my audio intuition).

This test result does not rule out a "demanding" combo that can easily pick up too much lowest-low frequency. Maybe there is a herring. But its not red?