Why are my woofers pumping?

Listening to vinyl rips from main system, on my cottage system. No pumping of course - the Aurum Cantus speakers only go down to 40 hz or so. So music is limited but it also sounds nicely peaceful. No harm done - sins of omission not commision in the bass.

I think beyond the low cart-arm resonance we need to add the very fullscale speaker system in my main system. Four speaker Audiokinesis. Lots of woofer power. - Maybe other speakers is why some users and reviewers dont experience much problem.

Electronics bandwidth is an issue too- your amps are full power to 1Hz. Most tube amps can't go anywhere near that low.

But I have similar bandwidth with both the amps and speakers at home, yet don't experience this issue. I am using a Triplanar, which allows for a bit of adjustment of the mechanical resonance by using multiple weights for the counterbalance. My 'table is different too.

Its true that some lathes can impart low frequencies to the LP, but that usually occurs between tracks and also at the end, where the carriage for the cutter head is advanced at a higher rate than during a cut. It sounds like you are getting this pumping during cuts on the LP, so I would rule out the LP as the source.

I would try applying a light grease to the platter bearing, to see if it shuts it up. If so, I would be thinking that the platter bearing is worn as normally a light oil is used.

Thanks Atmasphere - yes the low reach of the amps in combo with the speakers  may play a role. But with the Triplanar you dont have the problem. Do you know the resonance of your arm cart combo?

Lathes - low frequency - ok - but if it happens between tracks why not also within them? I can see the pumping between tracks on my 'energetic' Lps. Not much within the tracks but i think this is because the music energy takes over the woofer. It does not show much but is still there. Giving more stress in the music. Just my suspicion.

Since degree of pumping varies with the LP and repeats precisely with the record's revolution, drive problems probably is not much involved - confirmed by cleaning belts and adjusting the player - no big difference.

I notice that Pink Floyd Echoes recorded from the LP on my system pumps the woofers also on my cottage system! 

O_holter:  I'm convinced your problem comes from acoustical feedback. With a TT, placement is vital. I too had the same problem.  After months of experimenting, I found that TT platform isolation cured my problem. I built a suspended platform using heavy duty dampened springs and cables. (my room is on a suspended floor on the upstairs portion of my house that exasperates the problem)  I also noticed feedback on my Theta Miles CD player, when playing anything with a lot of elf and high db levels. I installed four steel cones on the bottom of the player and now I enjoy outputs of 90 db+, without any adverse effects on both playback systems. Most rooms have areas, where the low frequency is somewhat exaggerated. Be sure your TT, as well as your CD transport is not in one of these locations.