Resonance frequency testing: why does my cartridge have such a broad range?

[Faye_108]

I recently tested the lateral resonance frequency of my Denon DL-103R cartridge (w/ Technics SL1200 tonearm and heavier headshell) with the HiFi News Test Record.
To my surprise the wobbling and warbling happens on a very broad range. I think this is unusual and should not be the case.
It begins at 10hz and stops at 7hz.
The calculated frequency on resfreq.com is 8.3hz, so it lies more or less in the middle between the 10hz and 7hz.

Do I have a problem? If so, what could be possible reasons?

[nat]

Does the wobbling and warbling happen when you are playing music, not test tones? Resonance testing tones and sweeps are often recorded pretty loud, because the point is the make the arm/cartridge resonate. Those are frequencies that are not normally found on actual records to listen to. If the arm behaves itself in normal use, don't worry about it.

[analogaudio]

the difference between 10Hz and 7Hz is not large and probably not significant, the result is close enough to the desired 10Hz value for performance to be satisfactory.

[Alec124c41]

Remember that the vibration of the cartridge is a bell curve, not a sharp spike. What you are seeing is quite normal.
The resonant frequency is deliberately placed an octave below the audible range, and well above the frequency of any warps.


Cheers,
Alec

[chiz]

I recently tested the lateral resonance frequency of my Denon DL-103R cartridge (w/ Technics SL1200 tonearm and heavier headshell) with the HiFi News Test Record.
To my surprise the wobbling and warbling happens on a very broad range. I think this is unusual and should not be the case.
It begins at 10hz and stops at 7hz.
The calculated frequency on resfreq.com is 8.3hz, so it lies more or less in the middle between the 10hz and 7hz.

Do I have a problem? If so, what could be possible reasons?

That particular record is of questionable accuracy for resonance frequency tests anyway as discussed here:

https://forums.stevehoffman.tv/threads/ ... es.159661/
http://db.audioasylum.com/cgi/m.mpl?for ... l&n=594322

[Faye_108]

Thank you for your replies.

Well...on the few records I have listened to so far I didn't notice any kind of wobbling. As @nat suggested, I should not be worried then.
What worries me instead are these 2 links that @chiz posted. They suggest that the actual frequencies are even lower on the Hifi News record. This means that my actual resonance frequency range is even lower, somewhere between 9.5hz and 6.2hz.
I don't really know what to do with this new insight. Judging from your replies it's ok just to let it be and keep listening to records, as long as the cartridge behaves. As long as I'm not damaging any records I'm fine with that.

@Alec124c41 Yes, I understand that vibration builds up and reduces in a bell curve. I was just somewhat surprised that the curve extends over such a long range in which the wobbling is clearly visible.

[tlscapital]

I recently tested the lateral resonance frequency of my Denon DL-103R cartridge (w/ Technics SL1200 tonearm and heavier headshell) with the HiFi News Test Record.
To my surprise the wobbling and warbling happens on a very broad range. I think this is unusual and should not be the case.
It begins at 10hz and stops at 7hz.
The calculated frequency on resfreq.com is 8.3hz, so it lies more or less in the middle between the 10hz and 7hz.

Do I have a problem? If so, what could be possible reasons?

Do you use the extra SL-1200 counterweight ? This should allow you to add some more mass (inertia) to the headshell and improve your DL-103R performance. Allowing you to reach toward the higher 10Hz + (preferred) resonance calculation.

[Alec124c41]

At this point, listen to the music. If you feel that the bass is a bit heavy, then you might want to drop the effective mass a hair. If you are happy with the sound, then don't worry about it.

Cheers,
Alec

[abs1]

I recently tested the lateral resonance frequency of my Denon DL-103R cartridge (w/ Technics SL1200 tonearm and heavier headshell) with the HiFi News Test Record.
To my surprise the wobbling and warbling happens on a very broad range. I think this is unusual and should not be the case.
It begins at 10hz and stops at 7hz.
The calculated frequency on resfreq.com is 8.3hz, so it lies more or less in the middle between the 10hz and 7hz.

Do I have a problem? If so, what could be possible reasons?

I believe that you're overthinking things. This can only lead you into a rabbit hole and spoil your enjoyment of the music that you're listening to.

Besides, the test record that you're using is highly questionable in the accuracy department and is over modulated.

Your DL-103R will work well in many tonearms. I've run mine in everything from a VPI gimbaled arm with a effective mass of 10.2g to a 12" Ortofon with a 28.5g effective mass. True, the 103R's sonic signature improves as you increase the tonearm effective mass, but don't let it get you carried away.

Anyway, who can prove what the exact compliance of a DL-103R really is, considering how Denon publishes the specs?

If it sounds good to you - it IS good 8)

Cheers,
Al

Cheers,
Al

[Laila1]

.....
Do you use the extra SL-1200 counterweight ? This should allow you to add some more mass (inertia) to the headshell and improve your DL-103R performance. Allowing you to reach toward the higher 10Hz + (preferred) resonance calculation.

Isn't it the other way around ie, the more mass on
the headshell the lower the resonance frequency?

[chiz]

What worries me instead are these 2 links that @chiz posted. They suggest that the actual frequencies are even lower on the Hifi News record. This means that my actual resonance frequency range is even lower, somewhere between 9.5hz and 6.2hz.

I did not mean to worry you, just pointing out that sometimes in this hobby the tools we choose to try and obtain accurate measurements cannot be trusted.

I would not attempt to calculate the resonant frequency either without a reliable figure for the compliance at 10Hz and even then the results are of questionable value according to this article:

http://korfaudio.com/blog32
http://korfaudio.com/blog33

As others have said, if it sounds good to you that is more important than how it measures.

[Sunwire]

Copied from a post I made a few months ago:
I don't trust the online calculators to figure out the resonant frequency of cartridge/arm combinations.

I don't think the figures for effective mass of tonearms and compliance of cartridges are dependable since every manufacturer may be calculating them differently and actual products may not meet the specifications anyway. The position of the tonearm counterweight and the amount of play time on the cartridge may affect these figures, too.

I recently have been playing around with measuring tonearm resonance directly using Audacity.
https://www.audacityteam.org/download/

If you can record from your preamp to your computer, you can download Audacity for free from the web and use it to make the recording. If you then look at the resulting recording using the "Plot Spectrum" tool on the "Analyze" menu, you can see exactly where YOUR tonearm and cartridge are resonating.

Here's a screen shot of a recording I made using a Technics EPC-p22 cartridge with Jico SAS stylus on a Technics SL-D93 turntable. You can clearly see the tonearm/cartridge resonance is between 8 and 9 Hz. A little lower compliance would be better on this tonearm.
EPC-22 SAS on SL-D93 with AT record clamp -

I have a lot more testing to do, but one thing I've noticed is that it seems to help to sample a large amount of the recording (about 2 minutes) in order to get a good reading of the tonearm resonance. If you sample a section that is too small, you will notice the resonant frequency is different for different sections of music. The difference is relatively small, however. I don't think I've seen a range of more than 1 Hz either way when I take several measurements from different sections of a record. So, if most samples show 10 Hz, it's very rare that any other measurement using the same cartridge and arm would be less than 9 Hz or more than 11 Hz.

I haven't figured out if there is a particular record that is best for this test. But I theorize that it's better to use a record of real music you listen to, rather than use a test record of pink noise or some other test signal. After all, you want to find out how the tonearm/cartridge behave when you're playing your music, not some test tone, right? So far, the resonance frequency doesn't seem to change when I try the same cartridge/arm combination with different records, so it may not make much difference. Sampling a "too small" amount of music does make a difference, however.

Despite my theory that using records of real music is best, this screen shot shows the result when playing the frequency sweep on the HiFi News Analog Test LP #2 (not real music). I'm using it as an illustration because the resonant frequency stands out so clearly on this shot.