Vinyl Asylum Welcome Licorice Pizza (LP) lovers! Setup guides and Vinyl FAQ. |
|
Simply drop the tonearm onto a blank portion (run-out area) of a stationary LP while digitally recording the cartridge output. You get a waveform that looks like this.
The beauty of this waveform is that not only can you measure resonance frequency, but you can also measure the damping ratio of the cantilever suspension.
The resonance frequency in hertz is the reciprocal of the waveform period.
The damping ratio, zeta, can be calculated by measuring the amplitude of two successive peaks and calculating the logarithmic decrement, delta, by applying the following equations.
Now, we can apply some slightly more elaborate resonance frequency equations that incorporate cantilever suspension damping into the mix.
The following waveform was produced from my Technics SL-1200 Mk2 with Denon DL-S1 cartridge mounted in the standard Technics headshell. I disabled the KAB tonearm fluid damper for this test so that only cantilever damping is being measured. Cartridge mass is 7-grams and mounting hardware is 0.7 grams. The Technics tonearm supposedly has 12-grams effective mass thus yielding a total effective mass of about 19.7-grams.
The reciprocal of the waveform period shows a cantilever suspension damped resonance of 8.60-Hz.
The damping ratio computes to 0.1066 and total effective mass is 19.7-grams yielding a cartridge compliance of 17.19-mm/N.
Best regards,
John Elison
This post is made possible by the generous support of people like you and our sponsors:
Topic - Yet another way to measure arm/cartridge resonance... - John Elison 22:07:47 03/6/10 (32)
- RE: Yet another way to measure arm/cartridge resonance... - Luckydog 16:22:26 03/7/10 (4)
- RE: Yet another way to measure arm/cartridge resonance... - John Elison 20:40:05 03/7/10 (2)
- RE: Yet another way to measure arm/cartridge resonance... - Luckydog 14:50:54 03/8/10 (1)
- RE: Yet another way to measure arm/cartridge resonance... - John Elison 17:09:54 03/8/10 (0)
- RE: Yet another way to measure arm/cartridge resonance... - Luckydog 16:13:56 03/9/10 (0)
- RE: Yet another way to measure arm/cartridge resonance... - John Elison 17:28:01 03/9/10 (0)
- Done some models that support your method - Luckydog 13:43:55 03/10/10 (0)
- RE: Yet another way to measure arm/cartridge resonance... - Luckydog 16:22:52 03/9/10 (0)
- Runout groove - Mark Kelly 18:07:02 03/7/10 (0)
- Not quite - Mark Kelly 03:21:05 03/7/10 (22)
- Nothing you've written or presented contradicts anything in my post, so what's your point? - John Elison 09:46:07 03/7/10 (14)
- I misread your calculation, my apologies. - Mark Kelly 14:58:48 03/7/10 (13)
- Apology accepted! Thanks, Mark... - John Elison 15:29:58 03/7/10 (12)
- RPN - Mark Kelly 18:03:12 03/7/10 (11)
- RE: RPN - John Elison 19:10:15 03/7/10 (10)
- Were you able to measure a much lower Q and - Ivan303 17:07:59 03/8/10 (3)
- RE: Were you able to measure a much lower Q and - John Elison 18:00:42 03/8/10 (2)
- So the slew rate or rate of change is the same... - Ivan303 21:03:36 03/8/10 (1)
- I have no idea what you're talking about. Sorry! (nt) - John Elison 21:51:01 03/8/10 (0)
- RE: RPN - dave slagle 07:08:03 03/8/10 (4)
- High Pass - Mark Kelly 15:44:49 03/8/10 (2)
- RE: High Pass - dave slagle 18:09:05 03/8/10 (1)
- I can't get it to add up - Mark Kelly 23:30:27 03/8/10 (0)
- BINGO! - Ivan303 08:27:50 03/8/10 (0)
- I'm not sure - Mark Kelly 23:01:26 03/7/10 (0)
- RE: Not quite - Story 08:59:16 03/7/10 (6)
- I'll second that.....kudos. - jihad 11:05:50 03/7/10 (0)
- Thank you! :-) (nt) - John Elison 09:12:13 03/7/10 (4)
- Using the exact same calculations... - Ivan303 09:15:43 03/7/10 (3)
- RE: Using the exact same calculations... - John Elison 10:55:14 03/7/10 (2)
- RE: Counterintuitive... - Arlekino 06:39:00 03/8/10 (1)
- Tonearm vs brush - Thomas_A 11:50:02 03/9/10 (0)
- RE: Yet another way to measure arm/cartridge resonance... - Carolus 23:37:44 03/6/10 (3)
- RE: Yet another way to measure arm/cartridge resonance... - John Elison 00:01:05 03/7/10 (2)
- Why would having a blank side spinning be wrong? ... - andyr 01:18:18 03/7/10 (1)
- I never said it would be wrong, but I didn't do it that way... - John Elison 08:53:19 03/7/10 (0)