Speakers "pumping" with record warps - normal?

I just set up my Technics SL-3200 with an AT440MLa cartridge, Sumiko headshell, and Herbies mat. The table is properly isolated on a Target shelf that is mounted to wall studs. Using the Hi-Fi News test record, I determined that the resonant fequencies of the tone arm are approximate 8Hz (vertical) and 7Hz (lateral).
I've noticed that on warped records, the speaker cones do a lot of low-frequency pumping (visible movement in and out). I'm afraid that I could damage the drivers if I turn up the volume. Is this a normal consequence of warped records, or do I have a resonance problem with my TT?
Yep it's 'normal' (I use the term normal very loosely) and you could most certainly damage your speakers.

You can solve the problem by using a rumble filter - KAB makes quite a nice one that doesn't cost an arm and a leg.

I had this problem when my table was just _slightly_ off level due to a platform settling. Leveled it again; problem gone. Hope yours is that simple!
Dear Mika: I think that it because of the same trouble that you already posted where I give my advise:


The Ablang post is a good one tp check about.

Regards and enjoy the music.
Hi Raul -
I've measured the reonant frequency of the tonearm/cartridge combo - it's roughly 8Hz (at the low end of the desirable range).
If I want to increase the resonant frequency, I'd have to find a cartridge with an even lower compliance... is there such a thing? I thought that the AT440MLa is about as low as the come... any recommendations?
I had the same problem once, and discovered it was a very low "hum" which came from the wall power. I changed power cords and it went away.
Anything that moves your stylus/cantilever will translate to speaker movement. That's always been a factor with turntable/cartridge systems. If you can find a record clamp or weight that will take out some of the warp, it will help. Hopefully you're not using any kind of bass boost or "loudness" control in your listening. If the speakers don't exceed their linear range, or bottom out: there shouldn't be any damage to the system. With regard to your tonearm/cartridge resonance: 8hz is above record warp freq., and below audibility(close to the lower end of ideal). For more insight: (http://www.gcaudio.com/resources/howtos/tonearmcartridge.html) If your house is of frame construction: mounting a turntable platform to the wall is not a great idea.
What are people's thoughts on using a little bit of tonearm damping to help reduce this? I think that's onle of the reasons those trouchs/cups/whatever are built into the bearings, no?

The issue I see with using tonearm dampening is that it will affect the entire frequency range. If the woofer excursions are only with warped lps I can't see subjecting the entire vinyl collection to the dampening because of a few warped lps.

I think it is important to make sure these excursions are not pushing the amp into clipping. It takes large amounts of current to move those woofers like that, even if you don't hear any sound.