The Courteous Vinyl Playback Discussion

[Snoopy]

Look like crap , send it back

Well I’m kinda done with Blue Note Classics , and most new LPs reissues. Literally returned every Blue note classic and a bunch more from other labels.

Verve AS series didn’t disappoint me yet. But they are overpriced as well in Europe.

Only used vintage stuff from now on.

Just placed a order for 15 used Japanese LPs ( from 1977 - 1985). Best thing Is they are all VG+ and NM and the whole order is only 122 euro.

 

[undeakyetonde]

Hi folks, maybe somebody can help me understand a thing about how record playing works

When discussing vinyl playback, people often mention that tonearm and cartridge must match in some way. A cartridge+tonearm system that tracks a record has a resonance frequency, and common wisdom suggests that it should be around 8 Hz - 12 Hz when components are properly chosen and set up, etc etc. The exact frequency and width of the frequency region depend on tonearm mass, cartridge suspension compliance, and probably other things.

Here's what I don't understand.

Let's say we have a vinyl playback system with an MM cart, in which resonance frequency of the tonearm+cartridge combination is 10 Hz. We play a record, we record output of a (flat FR) phono preamp to a digital file. If we compute an amplitude spectrogram of the recording, the spectrum will have a peak at 10 Hz. This means that the signal generated in the coils has a lot of energy at 10 Hz. Signal in the coils is generated when the magnet moves, meaning that magnet moves at 10 Hz with a rather large amplitude (above thermal movements or whatever). The magnet is connected to the stylus via the cantilever, so the stylus also should move at 10 Hz at comparable amplitude.

So, if cartridge/tonearm have resonance at 10 Hz, does it make the stylus to just bounce back and forth at 10 Hz? Sounds like this bouncing should interfere with our goal - to accurately track the groove, to move the magnet, to generate current in coils, and so on. Shouldn't this bouncing introduce mis-tracking, distortion in the audible range? If no, why? If yes, what kind of distortion and how much exactly?

I'm not good at mechanics. Please tell me where I'm wrong. Thanks.

 

[Newman]

So, if cartridge/tonearm have resonance at 10 Hz, does it make the stylus to just bounce back and forth at 10 Hz?

No, the resonance isn’t a force, it is a response. Something else has to provide the force at 10 Hz. This might be a sharply warped record, for instance. If there isn’t anything providing the stimulus at 10 Hz, then the system won’t resonate.

 

[undeakyetonde]

No, the resonance isn’t a force, it is a response. Something else has to provide the force at 10 Hz. This might be a sharply warped record, for instance. If there isn’t anything providing the stimulus at 10 Hz, then the system won’t resonate.

Thanks, that makes a lot of sense. Still, we would have a peak on the spectrum of a captured signal, even if the 10 Hz stimulus isn't there, just noise. Does that mean that the system just responds less to stimuli with the same amount of energy, but outside the resonance region?

Also, why did companies like Sony, Denon, JVC make electronically damped tonearms? Was that just a hi-tech gimmick, or was there a rationale to it? Given a well-matched tonearm+cartridge, what's the difference in playback between damped and non-damped tonearm?

 

[Newman]

Thanks, that makes a lot of sense. Still, we would have a peak on the spectrum of a captured signal, even if the 10 Hz stimulus isn't there, just noise.

"...we would have a peak...", are you saying you have measured such a peak? If the stimulus wasn't there, the peak shouldn't be there. OTOH if the stimulus was "just noise", you would need to check to see if the noise included 10 Hz or not. If it did, then that is your stimulus for the peak.

Does that mean that the system just responds less to stimuli with the same amount of energy, but outside the resonance region?

It does respond less. But I'm not sure if it is a logical consequence of what you wrote before, because I'm not exactly sure what your first paragraph is saying.

Also, why did companies like Sony, Denon, JVC make electronically damped tonearms? Was that just a hi-tech gimmick, or was there a rationale to it? Given a well-matched tonearm+cartridge, what's the difference in playback between damped and non-damped tonearm?

I'm not familiar with those tonearms, so can't help you there. But in principle, to dampen the resonance of a tonearm-stylus system is not a gimmick.

 

[undeakyetonde]

"...we would have a peak...", are you saying you have measured such a peak? If the stimulus wasn't there, the peak shouldn't be there. OTOH if the stimulus was "just noise", you would need to check to see if the noise included 10 Hz or not. If it did, then that is your stimulus for the peak

I’m assuming that stimulus is vibrations from a rotating vinyl record on a turntable. There is always a noise floor, which comes from imperfections of the material, or from motor vibrations reaching the stylus. Either way, I think it is pretty safe to assume its spectrum doesn’t have a peak at 10 Hz, but most likely has *some* energy in region of the peak. It is not dead quiet.

Given there’s a stimulus with flat spectrum (or tilted) at the input, a system with resonance at some frequency should show a peak in its response, is that correct?

And yes, pretty much any vinyl transfer (digitized signal from output of a phone preamp while the record is playing) contains such a peak in the infrasonic region. Assuming no high pass filters in the chain, of course. I’ve seen in my personal captures, I’ve seen it captures available on the internet, with peaks in consistent places when done with the same gear.

Edit: didn’t take long to find an example posted on ASR: https://www.audiosciencereview.com/...ta-pyxi-phono-stage-review.45076/post-1612389

I'm not familiar with those tonearms, so can't help you there. But in principle, to dampen the resonance of a tonearm-stylus system is not a gimmick.

Let me rephrase. Let’s say that resonance of a tonearm-cartridge system is below audible range, and above frequency of warps, record eccentricity, etc

Would this damping have a positive effect on groove tracking? Is it any more useful than a proper high pass filter in the preamp?

 

[dlaloum]

I’m assuming that stimulus is vibrations from a rotating vinyl record on a turntable. There is always a noise floor, which comes from imperfections of the material, or from motor vibrations reaching the stylus. Either way, I think it is pretty safe to assume its spectrum doesn’t have a peak at 10 Hz, but most likely has *some* energy in region of the peak. It is not dead quiet.

Given there’s a stimulus with flat spectrum (or tilted) at the input, a system with resonance at some frequency should show a peak in its response, is that correct?

And yes, pretty much any vinyl transfer (digitized signal from output of a phone preamp while the record is playing) contains such a peak in the infrasonic region. Assuming no high pass filters in the chain, of course. I’ve seen in my personal captures, I’ve seen it captures available on the internet, with peaks in consistent places when done with the same gear.

Edit: didn’t take long to find an example posted on ASR: https://www.audiosciencereview.com/...ta-pyxi-phono-stage-review.45076/post-1612389


Let me rephrase. Let’s say that resonance of a tonearm-cartridge system is below audible range, and above frequency of warps, record eccentricity, etc

Would this damping have a positive effect on groove tracking? Is it any more useful than a proper high pass filter in the preamp?

Yes... the resonance is a motion of a "spring" system... and the arm, cantilever system is moving with that resonance - damping the 10Hz resonance will result in improved tracking through the entire frequency range as the arm is kept still.

This damping can be achieved through mechanical sprung/elastomer systems, oil/hydraulic, magnetic, or electro-magnetic means.

It needs to be applied judiciously, as too much will limit arm movement, and worsen performance by providing resistance to the arm motion...

In appropriate small amounts the damping can allow cartridge/cantilever compliance mismatches with tonearm mass to work remarkably well, by damping the resonance... but again if the resonance is too far out, or too high then damping it would require excess damping to be applied which then worsens overall performance.... so balance is needed!

 

[undeakyetonde]

Yes... the resonance is a motion of a "spring" system... and the arm, cantilever system is moving with that resonance - damping the 10Hz resonance will result in improved tracking through the entire frequency range as the arm is kept still.

That's great

Is the improved tracking measurable in any way? Or is it just a common wisdom that damping gives better tracking? Do we maybe get less harmonic distortion?

 

[Bob from Florida]

That's great

Is the improved tracking measurable in any way? Or is it just a common wisdom that damping gives better tracking? Do we maybe get less harmonic distortion?

You can verify tracking improvements by using the resonance tracks on a test record. Hi Fi News test record has both vertical and later sweep tracks to test for resonance. You also have 300 HZ track-ability tracks in 3 different locations.
A well match cartridge - arm is always desirable. Damping is a way to try and "fix" cartridge - arm matching.

 

[undeakyetonde]

You can verify tracking improvements by using the resonance tracks on a test record. Hi Fi News test record has both vertical and later sweep tracks to test for resonance.

That is a test for "how well cartridge+tonearm" tracks a groove with infrasonic content. Well audible modulations of the main tone means we arrived at the resonant frequency of tonearm+cartridge. I don't understand how this test shows anything about how well a cartridge+tonearm system tracks music. I don't think people wilfully press 10 Hz content into their LPs.

You also have 300 HZ track-ability tracks in 3 different locations.

That's great, but how can damping at 10 Hz (or wherever resonance of a specific tonearm+cartridge lies) improve 300 Hz trackability? Or trackability of other audible signals, like music? This is exactly what I don't understand. What would be the mechanical reason for it? What would be the measurable positive consequences of damping, in audible band? Would we have lesser THD or IMD?

A well match cartridge - arm is always desirable. Damping is a way to try and "fix" cartridge - arm matching.

That makes sense. But the original question was about usefulness of damping the resonance when cartridge and arm are already matched and resonance lies in the acceptable region.

 

[Bob from Florida]

That is a test for "how well cartridge+tonearm" tracks a groove with infrasonic content. Well audible modulations of the main tone means we arrived at the resonant frequency of tonearm+cartridge. I don't understand how this test shows anything about how well a cartridge+tonearm system tracks music. I don't think people wilfully press 10 Hz content into their LPs.


That's great, but how can damping at 10 Hz (or wherever resonance of a specific tonearm+cartridge lies) improve 300 Hz trackability? Or trackability of other audible signals, like music? This is exactly what I don't understand. What would be the mechanical reason for it? What would be the measurable positive consequences of damping, in audible band? Would we have lesser THD or IMD?


That makes sense. But the original question was about usefulness of damping the resonance when cartridge and arm are already matched and resonance lies in the acceptable region.

The vertical and lateral low frequency sweeps identify when the cartridge - arm resonance is excited and causes the stylus to start "dancing" out of the groove. You can test this -with and without damping and see if the dance attenuates with damping.
The 300 HZ track-ability tracks are at +15 db. If the damping is helping, then you should be able to hear / measure less distortion with the damping - if it is doing anything to help.
Keep in mind - you can measure improvements that are below audibility.

 

[Bob from Florida]

Here is an article from 1995 by Bob Graham - on damping.

Tonearm Damping Article By Bob Graham The BAS Speaker Volume 3 No. 4, January 1995

Tonearm Damping Article By Bob Graham The BAS Speaker Volume 3 No. 4, January 1995, Enjoy the Music.com Review Magazine

www.enjoythemusic.com

 

[dlaloum]

You can verify tracking improvements by using the resonance tracks on a test record. Hi Fi News test record has both vertical and later sweep tracks to test for resonance. You also have 300 HZ track-ability tracks in 3 different locations.
A well match cartridge - arm is always desirable. Damping is a way to try and "fix" cartridge - arm matching.

Even a well matched arm/cartridge will be improved with a bit of damping!

Lower compliance cartridges also tend to have more damping built into the cantilever suspension....

Very high compliance cartridges (like the late 70's 50cu cartridges!) - have very close to zero damping

Different cantilever suspension compounds have different amounts of damping ....

So yes even a "perfectly matched" cartridge/arm setup - with the resonant frequency, can use damping.

The perfect match just "places" the resonance where it can do the least harm.... but it is still present, and still causes issues - hence a touch of damping, combined with a perfect match is the optimum balance.

 

[Bob from Florida]

Even a well matched arm/cartridge will be improved with a bit of damping!

Lower compliance cartridges also tend to have more damping built into the cantilever suspension....

Very high compliance cartridges (like the late 70's 50cu cartridges!) - have very close to zero damping

Different cantilever suspension compounds have different amounts of damping ....

So yes even a "perfectly matched" cartridge/arm setup - with the resonant frequency, can use damping.

The perfect match just "places" the resonance where it can do the least harm.... but it is still present, and still causes issues - hence a touch of damping, combined with a perfect match is the optimum balance.

Once you've had an oil spill and the subsequent cleanup, the enthusiasm for dampers will dampen.

The right way to do it is the way Graham does it with his uni pivot arms. Downside is the high cost of admission.

 

[egellings]

No, the resonance isn’t a force, it is a response. Something else has to provide the force at 10 Hz. This might be a sharply warped record, for instance. If there isn’t anything providing the stimulus at 10 Hz, then the system won’t resonate.

Also, any damping in the system could reduce the amplitude of the resonant movements or at least make it fade more quickly after a stimulus for it passes.

 

[undeakyetonde]

If the damping is helping, then you should be able to hear / measure less distortion with the damping - if it is doing anything to help.

So, if it helps, helps. If not, then not. Huh.

The question was: if damping would help, *why* would it help, mechanically speaking?

Here is an article from 1995 by Bob Graham - on damping.

Tonearm Damping Article By Bob Graham The BAS Speaker Volume 3 No. 4, January 1995

Tonearm Damping Article By Bob Graham The BAS Speaker Volume 3 No. 4, January 1995, Enjoy the Music.com Review Magazine

www.enjoythemusic.com

"As for my own arm and cartridge, the XLM has never sounded so good. The previously annoying records are now playable with absolutely no "bounce," no warbling tones. The stylus stays virtually motionless (to the eye) relative to the tonearm, so I'm not generating low-frequency tones to modulate all my music."
"Although my system is somewhat clumsy-looking, the improvement in performance is so profound, particularly with a high-compliance cartridge, that I would not consider being without it."

Idk, sounds like common audiophile talk, not a technical article. I looked the guy up, he sells $7000 tonearms.

So yes even a "perfectly matched" cartridge/arm setup - with the resonant frequency, can use damping.

The perfect match just "places" the resonance where it can do the least harm.... but it is still present, and still causes issues - hence a touch of damping, combined with a perfect match is the optimum balance.

Do you mind explaining what issues exactly? Does the resonance cause any issues with a flat record? If yes, why does damping solve them?

 

[dlaloum]

So, if it helps, helps. If not, then not. Huh.

The question was: if damping would help, *why* would it help, mechanically speaking?

"As for my own arm and cartridge, the XLM has never sounded so good. The previously annoying records are now playable with absolutely no "bounce," no warbling tones. The stylus stays virtually motionless (to the eye) relative to the tonearm, so I'm not generating low-frequency tones to modulate all my music."
"Although my system is somewhat clumsy-looking, the improvement in performance is so profound, particularly with a high-compliance cartridge, that I would not consider being without it."

Idk, sounds like common audiophile talk, not a technical article. I looked the guy up, he sells $7000 tonearms.

Do you mind explaining what issues exactly? Does the resonance cause any issues with a flat record? If yes, why does damping solve them?

There is no such thing as a perfectly flat record... and the surface noise itself is wideband - so there will be stuff within the resonant "peak" of the suspension/mass system.

That means that the arm will be cycling up/down around the resonant frequency (in a perfectly matched setup, circa 10Hz)...

It will do that because it is triggered by anything that is close to that freqency, the less triggering vibrations there are, the better, obviously - but things like feedback and footfall will also trigger issues - any form of vibration/motion.

So now picture the mechanicals.... the headshell is riding up and down, drawing a simple sine wave at 10Hz in space... the needle is in the groove, but as the head moves up and down, the cantilever angle changes, keeping the needle in the groove... the angle of the needle is being changed vis-a-vis the surface of the record ...
Also the pressure of the needle on the surface of the record is varying, being higher on the upswing, and lower on the downswing, with peaks/trough of pressure at the extremes. (this means it then affects EVERYTHING the needle is trying to read from the record surface... all frequencies...)

Damping basically absorbs the energy of the resonance... instead of generating up/down motion, it is removed/absorbed via one of the various available damping mechanisms (typically that means it is converted into heat... but the energy amounts involved are so small that you would be highly unlikely to be able to sense it without very sensitive instrumentation)

You don't want to absorb so much energy that the arm motion on the surface of the record is constrained - it still needs to follow the groove, as well as the imperfect surface of the record (no such thing as a flat record... not at the scale of the needle/cantilever)... so it is a balancing act... you adjust the system to get the resonant frequency to where it can do the least harm, and is least likely to get triggered... or triggering is minimised (10Hz is the typical recomendation, to keep it away from footfall, environmental vibrations at 3hz to 4hz, and keep it away from recorded material starting at 20Hz) - and then you use damping, to reduce the resonance.

 

[Bob from Florida]

So, if it helps, helps. If not, then not. Huh.

The question was: if damping would help, *why* would it help, mechanically speaking?

"As for my own arm and cartridge, the XLM has never sounded so good. The previously annoying records are now playable with absolutely no "bounce," no warbling tones. The stylus stays virtually motionless (to the eye) relative to the tonearm, so I'm not generating low-frequency tones to modulate all my music."
"Although my system is somewhat clumsy-looking, the improvement in performance is so profound, particularly with a high-compliance cartridge, that I would not consider being without it."

Idk, sounds like common audiophile talk, not a technical article. I looked the guy up, he sells $7000 tonearms.

Do you mind explaining what issues exactly? Does the resonance cause any issues with a flat record? If yes, why does damping solve them?

I think you are over analyzing this. Simply put, if the tonearm resonance gets excited by a warp, the damping device will limit the excitation amplitude and duration.
Check out the Korf blog for some additional info on resonances and other general turntable info.

 

[undeakyetonde]

So now picture the mechanicals.... the headshell is riding up and down, drawing a simple sine wave at 10Hz in space... the needle is in the groove, but as the head moves up and down, the cantilever angle changes, keeping the needle in the groove... the angle of the needle is being changed vis-a-vis the surface of the record ...

Doesn't angle of the cantilever change anytime it moves from side to side, meaning, anytime it reads a lateral modulation? Same for up and down and vertical modulation

Also, if the stylus is riding in the groove, reading audible signal, how can it draw a high-amplitude 10 Hz sine wave on top of that? Unless there's sine wave of that amplitude embedded into the groove I can't see how it could do it, there should be no space for the stylus to do that.

At this point I'm even convinced this 10 Hz high-amplitude component isn't really reflecting what is happening in the groove - maybe the tonearm wobbles at 10 Hz relative to the stylus in the groove, and this movement induces current in the cart. Even though we want only current cause my movements of stylus in the groove, we can't get it in isolation, since everything moves and interacts.

Also the pressure of the needle on the surface of the record is varying, being higher on the upswing, and lower on the downswing, with peaks/trough of pressure at the extremes. (this means it then affects EVERYTHING the needle is trying to read from the record surface... all frequencies...)

Why would we care about pressure on the surface if MM/MC cartridges measure velocity?

Basically you said "it wobbles at 10 Hz and it affects other wobbles at other frequencies". Sorry, but this doesn't seem a convincing scientific argument. In essence this is a statement about a tonearm/cartridge system being a nonlinear signal transducer. 10 Hz affects regions far from 10 Hz. While it makes sense, none of the above explanations say anything about the amount and inner workings of this nonlinear behaviour.

I hope somebody could give an explanation in terms of transducers (I guess cartridge could be called a seismic transducer?)

 

[Balle Clorin]

http://www.laudioexperience.fr/wp-content/uploads/2017/04/Bruel-Kjaer-Audible-Effects-of-Mechanical-Resonances-in-Turntables-AN17-233-1977-1.pdf