Why are my woofers pumping?

Dear @o_holter : Nice result you experienced with the Clavis ( that ovbiously is not even a " small " challenge for the great Atlas. ).

""" So the "subsonic overwork" of the woofers seems far less. Or mainly absent. """

Either the Clavis/Atlas compliance and weigth puts the resonance frequency in the " green " territory as you said. So, seems no trouble for that and very specific tonearm/cartridge resonance frequency issue.

I imagine that you already tested both cartridges using the SME V in static and balanced way about the VTF set up.

Your Atlas has over 1,500 hours of use that are not way higher but not way low number.
Trhough those 1,500 hours stylus tip and cartridge suspension are the ones that could starts to work outside manufacturer specs and I’m not saying that’s your case but only thinking " fully loaded voice ".

Who can tell you if any problem down there? not a single re-tipper but the manufacturer it self. maybe time to talk with J.Carr for he can take a look to your beloved Atlas.
In the mid time you can re-tip your Clavis with a re-tipper using boron cantilever and you will be surprised the Clavis improvements.

Anyway, I think you need to try JC directly.

R.

Invictus005 wrote: " This has to be the most ridiculous thread on Audiogon at the moment. Everything and all of it. OP, I told you it’s a problem YOU can’t solve. Just enjoy the music. Some of these things are just part of vinyl. Many comments here have crossed the line of insanity. Seems like some people want to end up in a mental hospital?"
Let me posit this in a positive way. "Sound is good. Relax. With a good cart you get some vinyl pumping. Look away". Ok? If so, I agree. Fits my evidence, mostly.

But the thread, even if ignorant or repetetive, is not ridiculous. A large list of potential problems, regarding low rumble and woofer pumping, has been listed and described. Even if low cart-arm resonance is the main culprit in my case, the suggestions are interesting on their own, for anyone investigating low frequency vinyl problems in resolving systems.

I was maybe a bit optimistic in my last post. The thread is all over the place, yes. But so are most of the threads I’ve read on this subject. Compare this one: https://forum.audiogon.com/discussions/the-arm-cartridge-matching-myth . Halcro argues that resonance means ca nothing, others don’t agree, kirkus has a good post stating that resonance is only a rough measurement, the cart-arm-combo acts as a high-pass filter. For an even more esoteric discussion, compare this: https://forum.audiogon.com/discussions/strange-tonearm-tweak-long

Back to testing.

I've brought my (quite worn)  Titan i down from the loft. And will connect it soon.

Since the Clavis creates less pumping (next to none), I would expect that the Titan comes in the middle (if the resonance theory is right). This is due to the weight differences (assuming that the 10hz compliance is much the same, maybe 21, as suggested earlier in this thread). The tonearm effective mass is 10.5g, the two screws add 1.1g (I measured), the Clavis 9.5g. This gives a 7.6 hz resonance, according to the calculator. With the heavier Titan at 10.5g, there should be a 7.4 hz resonance. And with the heaviest Atlas at 11.6g, a 7.2 hz resonance.

This fits somewhat with my results, but I wonder if the compliance of the Clavis is in fact lower. Since woofer pumping goes from visible and maybe a problem with the Atlas, to not much visible, with the Clavis.

It may be that the wear and tear on the cartridge suspension plays a role here. The Clavis has only 200 hours, the Titan maybe 2200, the Atlas 1600 (rough estimates). My audio friend Eirik remarked that he had not noticed this pumping problem earlier, in my system. Myself, I am not sure, it may have been going on as long as I've used the Atlas, only we did not look for it, or it may have become stronger over time. I remember that, as the Titan became more worn, I had some rumble and bass problems, but I am not sure if the Titan was the culprit.

So it will be interesting to reinsert it into the system and hear how it compares with the Atlas. Like I've told you, ten minutes with Clavis made me think, this is decent, even very good - and then I ached to get back to the wider and deeper soundscape of the Atlas. Pumping woofers or not. The Titan should perform in a middle zone, but closer to the Atlas.

Testing the Titan i (ca 2008 model).

To my surprise, there is little to no subsonic pumping. Much like the Clavis. Or maybe a little more. But clearly different from the Atlas. The woofers are more engaged, more vibrations, changing from Clavis to Titan - but this fits what I hear, it is fast vibrations, not pumping.

Sonically the Titan is a clear step up from the Clavis (today, also) with wider, deeper, better detail, better e g on female voices (R L Jones: Evening..). On Pink Floyd’s Echoes, the soundscape is now almost as large as with the Atlas, although still a bit more harsh, less natural, with some sibilants (I could cure some of it through adjustments).

I had expected a gradient, according to resonance theory. The Clavis should pump least, the Titan some, and the Atlas most.

But the results - so far - are more one of a kind. The Atlas pumps, the others don’t. This makes me suspect suspension wear or some other non-optimal condition in the Atlas. Yet I was surprised to find no signs of pumping with the Titan - since this has been used maybe 500-800 hours longer than the Atlas, so if suspension slack, wear and tear, is the culprit, it should show up there. But no.