Why are my woofers pumping?

>>>>>> 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. <<<<<<

In the day of phono only they had a button sometimes labeled "Rumble filter."  That's what you got.  Others may say "Low filter."  Interaction between the cartridge, tonearm and record cause ir.

Does your turntable have an attached cover? If yes, it catches low frequency audio like a sail catches wind. See if removing it reduces the feedback. If yes but you still  want to keep the cover attached, rotate it perpendicular to the speakers to at least reduce the pickup. Worked for me! Just a thought. - Andy

Whatever you do, don’t get a subsonic filter, unless of course you want to kill good sound.

This is nonsense. I use the cheap DB Systems filters and the loss in fidelity is barely perceptible.

I also discovered that, indeed, "silent" record grooves are not the same.

You discovered that subsonic noise is often cut into the grooves. This is why you're not getting pumping in the runout grooves. I once believed warps were the major culprit. They’re not. It’s usually acoustic feedback and poor album cuts

Read some of the reviews on these:

http://store.acousticsounds.com/d/60042/DB_Systems-DB_Systems_Subsonic_Filter-Turntable_Accessories

At only $20, it can’t hurt to try them. If you like the result, consider investing in the DB-12 or KAB filter.

+1 tkr and stereo5! A well designed subsonic filter (KAB) will do wonders for bass in your system! 

Thanks, all! I think we can conclude that

1) the Atlas / SME V combo is very “receptive” in the lowest frequencies, and that in some resolving systems this may give unwanted effects like woofer pumping.

2) this is mainly a resonance problem, not a rumble or player noise problem (it does not change much, with different platter mats, damping or stabilizing the turntable, etc), and the first measure is to try to move the resonant frequency up - reduce the effective mass of the arm. This is only slightly possible on the SME V, but even small changes may help

3) the somewhat "over-eager" reception at the lowest frequencies of the Lyra/SME combo makes it even more important to correct any residual system noise, drive noise or rumble.

4) if the problem persists, try a rumble filter.

I will now try to decrease system noise – check the turntable, bearing, oil, feet, etc.

I wonder, even if the pumping is already reduced, would a filter be an idea anyway? Are my woofers straining too much, in the lowest bass? Is this prone to happen more, when the suspension of the cartridge is more worn?