The sound of compliance mis-match

[Phoca]

When trying to fit a modern cartridge to my Kenwood KP-4021, I found I had to add mass to the headshell to get it to balance. Also needed it for shimming the cartridge to get VTA/stylus rake set correctly. There may be a VTA adjustment for the arm, but I'm not ready to play around with it yet (I've not found any manual anywhere that mentions anything about VTA, though there are two screws at the base of the arm unit).

In fact I had to add 3 pennies to deal with both issues. And that, obviously, adds quite a lot of mass to the arm. Now I don't have an effective mass for the arm so don't know how to determine compliance needs other than to listen for problems.

So my question is, if there is a mis-match, what would it sound like? I know the resonance that is thought to be the problem is sub-sonic, but if it's a concern at all, it must have some sonic signature (otherwise, why would we worry about it unless it causes record damage somehow - not likely given its low Hz). I've read that it's the overtones that end up causing a veiled, slurred sound quality. Any comments?

Thanks, all.

[lynnot]

Hi,

your Kenwood should accept regular cartridges with a nett weight between approx. 5 and 10 grams. Did you choose to mount an ultra light Ortofon OM cartridge?

Rgds, L.

[Ldg]

Mismatching sounds almost like vibrato, or modulation where there should be none. Notable on piano, for example, even in small doses. Or a general slight pitch muddling which can come across as poor general clarity. An unnaturalness. It can also affect lf level and sense of bass timing.

In extreme, it mucks up tracking too, even to the point of stylus flying out of the groove. Or generally degrading tracking, bringing forward the onset of mistracking distortion.

HTH !

[Phoca]

Nope, I was mounting an AT440MLa at 6.5g, and it's too light to balance without added weight. This table comes with a pivoting (!) metal cartridge insert for the headshell in which is mounted a cartridge with no mounting tabs (it's not a p-mount, just has no mounting screw holes). You can see it in my Kenwood KP-4021 thread here:

viewtopic.php?f=18&t=28325&p=358180#p358180 (can't figure out how to link to a specific post, but it's near the bottom).

I was able to get the AT reasonably well mounted, though it's impossible to align perfectly b/c when it is aligned at one null point, the other is off no matter how far forward or back, nor how straight or twisted I get it in the headshell. I think it's a Baerwald protractor, but not sure. This is a different issue, but despite less than perfect alignment, it sounds pretty darn good.

So I'm still interested in the sound of compliance mis-matches. By adding the pennies, I'm thinking I've made mess of something, and compliance mis-match seems like the obvious bugaboo. How would I know if I had such a mismatch?

Thanks again.

[Ldg]

Listen to a piano sonata, you'll hear unnatural modulation on notes with long sustain. Pianos don't have vibrato ! It can be subtle, or pretty obvious.

[Phoca]

Thanks, ld. This helps. So would it only show up on certain frequencies, or would it likely be present across the board?

Interestingly, I've heard piano vibrato or modulation on one or two records (just heard it today on a copy of Supertramp's Even in the Quietest Moments, on "Downstream"). I've always chalked that up to something in the recording, and since I'm hearing it on a Denon DL-110 that I just mounted on a Thorens TD-165, which seems like good match, I'm thinking it's not compliance mismatch in this case.

The AT440MLa sounds pretty clear and I haven't heard the modulation or vibrato yet (other than the Supertramp song, which I just listened to and sounds just like the Thorens/DL-110), so maybe there's no problem.

[Ldg]

It's present across the board. Just that piano shows it up well, because it sounds unnatural. Classical sonatas are mostly very well recorded and I find easy to hear, even in small doses. Rock piano recordings less guaranteed, and might be anything. I haven't got that Supertramp recording to check, BTW.

[Phoca]

Do you have a suggestion of a few sonata recordings that would show it well that I could try out? I'm willing to look for one just to educate myself. Or does the HiFi News test record have a track that would demonstrate it if it exists?

[Ldg]

Pretty much any of the Beethoven or Schubert piano sonatas, on Decca, Deutsch Grammophon, Philips labels. But any solo classical piano work on a quality label will do it. There's no music on the HFNTR, IIRC. You could listen to a tone, but couldn't then relate it to real music. Piano is best for this practical test, IMO.

[dlaloum]

The HFNTR does have a low frequency sweep with a 1kHz tone superimposed.

If you run the sweep, you will visibly see the cartridge "dance" when it hits the resonance - some cartridges more than others (regardless of where the resonance is located!)

Audible you will here the 1kHz tone go into vibrato mode... and you will hear it getting worse as it reaches the resonance peak and then fade away.

With the very high compliance SuperXLM on my mid mass JVC S-arm the mis-match was quite audible in music as well as on the test track.

With the arms servo damping activated, it would pass the test with nary a quiver.... and the sound smoothed out when playing music... (it is a very sweet cartridge!) - really the JVC is a mismatch with the SXLM ... which needs a low mass arm, but it can sound excellent on that arm due to the damping.
Of course it sounds even better on a low mass arm, with a touch of damping!

[Ldg]

Yes, matching is ultimately about stability. Making the most of what suspension damping there is, and applying arm damping that might be available. The 'rules of thumb' about frequency matching ignore damping. But happen to typically work because of happy coincidence.

Generally, zero arm damping often ends up somewhat underdamped, and a touch of arm damping can do wonders for stability.

A damping oriented approach to matching is far better in my book, but is a bit heavy on the theory and tools needed to achieve an optimum. But it's what I do. There's a sticky 'cartridge and tonearm damping' that goes into some of the theory, and provides some methods and tools. It is a bit heavy on the theory side, though !

[Phoca]

There's a sticky 'cartridge and tonearm damping' that goes into some of the theory, and provides some methods and tools. It is a bit heavy on the theory side, though !

Thanks, ld. I was just about to ask where I could read up on damping, as I may decide to experiment with that. Thanks also for the tip on sonatas, ld.

Dlaloum, I have thought about getting the HiFi News record for a while. Sounds like it might be time as I delver deeper into this vinyl thang.