Why are my woofers pumping?

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?

@o_holter - You mentioned earlier in the thread about an XLR filter. I was struggling with the same woofer pumping problem and finally commissioned Dan Satoni at DTS electronics to build a custom balanced high pass filter for me. Problem solved with no obvious loss of sonic performance. I know Dan has a minimum board order of 5 units so I am pretty sure he can quickly build another one for you if interested. It wasn't exactly cheap ($550 CAD) but I feel it was an exceptional value at that price.

Todd

VPI Classic 3 w/Lyra Delos -> Whest PS.RDT30 SE -> Custom Filter -> ARC Ref2 MkII -> ARC VT100 MkIII -> Magico S1

Please note that woofer pumping is not only caused by the cartridge/arm. Some CD's cause pumping as well. Hopefully you have a "low-cut" option. Use it only when needed.