Cartridge Compliance

the thin end of the wedge
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Post by Guest » 06 Nov 2010 23:38

BigE wrote:How do you separate the mass of the headshell from the effective mass of the arm?
It's easy at signal frequencies, just say that the armtube isn't rigid. If armtube flexes, all bets are off as to effective mass MOI based model, enter the TL model !

It's OK though at suspension/arm mass resonant type low frequencies, where wavelength is much longer than armtube. But signal frequencies..............yes, it's a can of worms on a slippery slope :wink:

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Re: Cartridge Compliance

Post by Luxman78 » 13 Aug 2019 10:53

I'm where this guy was in 2010. A lot of you (or perhaps former members) answered it doesn't matter, but I'm not stressing over details, I just need to know when buying a EU made cartridge for a Japanese TT, or vice-versa.

I'm also trying to go as high as possible with compliance for a certain tome-arm mass but not cross the line, which makes it even more important.

Also, our calculators here are n x 10-6, so if you enter 20 µm/mN you have no idea where you are with the resonant freq.

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Re: Cartridge Compliance

Post by Alec124c41 » 13 Aug 2019 12:32

The 1/2 inch mount is standard, around the world. The only thing that won't work is mounting a cartridge with threaded holes in the top to a headshell with threaded holes on the bottom, and there are few of those any more.
Trying to get as high a compliance as possible with a particular tonearm is like trying to put as soft a spring as you can in a car. It does not compute.
What arm do you have, and which cartridges are you considering?

Cheers,
Alec

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Re: Cartridge Compliance

Post by Luxman78 » 13 Aug 2019 18:14

Alec124c41 wrote:
13 Aug 2019 12:32
The 1/2 inch mount is standard, around the world. The only thing that won't work is mounting a cartridge with threaded holes in the top to a headshell with threaded holes on the bottom, and there are few of those any more.
Trying to get as high a compliance as possible with a particular tonearm is like trying to put as soft a spring as you can in a car. It does not compute.
What arm do you have, and which cartridges are you considering?

Cheers,
Alec
Thank you very much for your answer.

I asked for advice on a cartridge for a Technics SL-Q202 turntable with a 11g relative tone-arm mass. I got the advice that said Audio Technica should do fine and that it is an all around performer that can do various music styles to a certain degree. Not being able to read Japanese numbers for compliance, I didn’t know that the resonant freq. I got was a rather low 8.33 and that this cart might do well on perfectly flat records, but I don’t have many of those.

Sure enough I got the woofer pulsating with long, slow excursions.

I was convinced I got a good cart so I started worrying that there’s something wrong with my TT. I thought suspension, I thought platter friction, I thought acoustic feedback. I did a hundred tests and finally took it to the shop. Nothing wrong with the TT, I got a mismatch in tone-arm / cart resonant freq and it is augmenting the pulsation in the cones. So I want to move away from this range of 8-9Hz maybe closer to 11Hz.

There were three ways we calmed the cones down, the repairman and I; flat record, subsonic filter and a different cart.
Notice, when we replaced my cart for another one, the speaker cones had no pulsating even without a subsonic filter. I’d say that’s just a better match, but that was a very old Ortofon cart they don’t make any more so I couldn’t just buy that one.

Original cart specs for this TT said 10x10 but this is measured at 100Hz and I can’t find any reviews on the original cartridge (we haven’t got this one in VE database).

As a rule of thumb, one would calculate that 10x10 at 100Hz is 17.5x10 at 10Hz and the AT would be 12.25x10
The way I posed the question was; I know I shouldn’t go to high with compliance for a 11g tone-arm and all the calculators reassure me of this, but I’d like to go as high as possible for this specific tone arm without overdoing it.

Thanks again,
Kruno

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Re: Cartridge Compliance

Post by Alec124c41 » 13 Aug 2019 21:12

The choice would depend on your budget.
I think something with a compliance of about 20 should be good.
If you go too high, the bass gets bloated.
It is easier to add mass to the arm to fine-tune it, than to lighten it.

Cheers,
Alec

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Re: Cartridge Compliance

Post by Luxman78 » 13 Aug 2019 21:37

Alec124c41 wrote:
13 Aug 2019 21:12
The choice would depend on your budget.
I think something with a compliance of about 20 should be good.
If you go too high, the bass gets bloated.
It is easier to add mass to the arm to fine-tune it, than to lighten it.

Cheers,
Alec
Thank you! 20 always shows very bad figures when I use our calculator. My budget is alright to go even for a 150$ - 180$ cartridge ONCE. What I can't do is keep buying them and have bad results. That's why I try to use the calculator to see what can I expect. I gave 60$ for this combo already.

When I put a very light cartridge into the calculator and use 9 compliance, I get 11, which is recommended from what I gathered so far.

I'm not sure I understand what happens when I change the weight around the arm. I mean going 20, that's at the top of recommended for the 11g tone-arm, if I add a weight at the headshell wouldn't that make the CU even higher?

Also, it seems adding an extra weight at the counterweight side makes the tone-arm lighter... :? :?

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Re: Cartridge Compliance

Post by Alec124c41 » 14 Aug 2019 01:21

A compliance of 9 might be a bit low for that arm.
A low number means low compliance, i.e. a stiffer "spring." With a medium-light arm the resonant frequency would be a bit high, manifesting as a thin bass response. This can be alleviated by adding mass to the headshell, thereby lowering the resonant frequency, and increasing the bass response.
Note that the compliance numbers run down the left side of the chart. The numbers across the top are the weight of the cartridge.
A 5g cartridge with a compliance of 15 shows a resonance of 10 Hz.
A 5g cartridge with a resonance of 9 shows a response of 13 Hz, which is getting a bit high.

Cheers,
Alec

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Re: Cartridge Compliance

Post by lini » 14 Aug 2019 01:36

Kruno: Dynamic compliance usually refers to the horizontal plane, static compliance to the vertical plane. So if you'd like to ensure, that you get no problem with woofer pumping with somewhat warped records, you'd better get one of the new AT MMs from the AT-VM95 family, which have a significantly lower static compliance than the VM5x0/7x0 family models.

Greetings from Munich!

Manfred / lini

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Re: Cartridge Compliance

Post by Luxman78 » 14 Aug 2019 08:20

Alec124c41 wrote:
14 Aug 2019 01:21
A compliance of 9 might be a bit low for that arm.
A low number means low compliance, i.e. a stiffer "spring." With a medium-light arm the resonant frequency would be a bit high, manifesting as a thin bass response. This can be alleviated by adding mass to the headshell, thereby lowering the resonant frequency, and increasing the bass response.
Note that the compliance numbers run down the left side of the chart. The numbers across the top are the weight of the cartridge.
A 5g cartridge with a compliance of 15 shows a resonance of 10 Hz.
A 5g cartridge with a resonance of 9 shows a response of 13 Hz, which is getting a bit high.

Cheers,
Alec
Perhaps this is where I made a mistake in my calculations... You can't really calculate a 5g cartridge, right? You need to add the weight of the headshell and fasteners. My headshell alone is 9.4g
In that case I have tone-arm mass 11g + 14.4 combined cart and headshell which is then 24.4 and then I don't get 10Hz. And not just that, that is if you take a 5g example, but AT-VM95E is 6.1g, so it's 11+9.4+6.1 so now we have 25.5g.

Or should I leave out the headshell? (but this wouldn't make sense to me as not all headshells weigh the same)

Thank you for your time and effort!!
Last edited by Luxman78 on 14 Aug 2019 08:28, edited 2 times in total.

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Re: Cartridge Compliance

Post by Luxman78 » 14 Aug 2019 08:26

lini wrote:
14 Aug 2019 01:36
Kruno: Dynamic compliance usually refers to the horizontal plane, static compliance to the vertical plane. So if you'd like to ensure, that you get no problem with woofer pumping with somewhat warped records, you'd better get one of the new AT MMs from the AT-VM95 family, which have a significantly lower static compliance than the VM5x0/7x0 family models.

Greetings from Munich!

Manfred / lini
Thank you as well, Manfred. I will say I found your explanation on coverting compliance numbers to be of great help and I quoted you in another forum (I put your name under it) :D

It is exactly AT-VM95E I have now on my TT and the entire problem with woofer pumping (and they DO pump like crazy) comes from this cart precisely.

This entire voyage I undertook to find a matching cart, started with having woofers pumping very lively with AT-VM95E.

Thank you very much for your help, but unless I'm doing something wrong when calculating, that AT cart shows a rather low res. freq. of 8.3

I'd be happy to find myself between 10 and 11.

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Re: Cartridge Compliance

Post by Alec124c41 » 14 Aug 2019 14:38

The effective mass of an arm is usually quoted with the original headshell included. Therefore you can change this by changing the headshell.

Cheers,
Alec

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Re: Cartridge Compliance

Post by lini » 14 Aug 2019 14:49

Kruno: Hmmm, that's odd. There shouldn't be any problem with that AT on an arm, which is on the lighter side of medium heavy - but maybe you've got an exemplar with a rather loose suspension. That's not really typical for new (current production) ATs, though, and even in case of new old stock ATs it's not really a frequent problem - but it can happen, especially on old exemplars, on which the damper ring has shrunk enough to reduce the tension on the flexible filament between the visible part of the cantilever assembly and the rear part, that's fixed in the plastic holder. Unfortunately the VMN95E of your AT-VM95E will most likely belong to the AT needles, in case of which this fixation is done via rivet instead of via screw, so that the problem can't be easily cured.

Greetings from Munich!

Manfred / lini

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Re: Cartridge Compliance

Post by Luxman78 » 14 Aug 2019 16:35

Thank you both again!!

@Alec, In deed it says effective mass without cartridge, it doesn't mention headshell, so you say this is usually calculated with the original headshell?? This should make things easier... I hope...

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Re: Cartridge Compliance

Post by Luxman78 » 14 Aug 2019 16:43

Alec124c41 wrote:
14 Aug 2019 14:38
The effective mass of an arm is usually quoted with the original headshell included. Therefore you can change this by changing the headshell.

Cheers,
Alec
So, if it says 11g and I'm using another headshell, i should just make up for the difference?

Also, if I use Concorde that needs no headshell, the right calculation would be; 11 - 7,5(headshell) = 3,5 + 18,5(Concorde) so the total is 22g?

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Re: Cartridge Compliance

Post by Luxman78 » 14 Aug 2019 16:47

Alec124c41 wrote:
14 Aug 2019 14:38
The effective mass of an arm is usually quoted with the original headshell included. Therefore you can change this by changing the headshell.

Cheers,
Alec
Why does our calculator have a "fastener" section then? I must've been doing something wrong.