Resonant Frequency, Dynamic Complinace and Pickering question

inspiredsports

I'm delving deep into properly matching old vintage cartridge/stylus combinations with old vintage tonearms in order to avoid resonance problems. The cartridge/stylus/tonearm system has a "Resonant Frequency" that must be managed within a specific range in order to insure sound quality is not degraded.

The Resonant Frequency of the cantilever is the acoustic frequency (in Hz or "cycles per second") at which the cantilever will become overly excited and vibrate out of control. Resonant frequency of a cantilever is controlled by keeping the frequency in a range below human hearing, but not so low that it will become excited by external vibrations such as foot fall or record warp, or too high to get into the deep bass (15Hz) range of music. The ideal "Resonant Frequency" range is said to be 8 to 12 hz.

Within my tonearm collection are 3 with extremely light "Effective Mass" ratings. These tonearms require a cartridge/stylus combination with a high "Dynamic Compliance" rating. Dynamic Compliance is expressed as (DC X 10-6cm/Dyne) where "DC" is the Dynamic Compliance rating .

I have a New Old Stock Pickering XV-15 1200E (D1200 stylus) that was a pretty good cartridge in its day ($250 SR in the 1980's) and am unable to find its Dynamic Compliance rating (I'm hoping it is over 20).

Can anyone help?

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The Math:

RF = 159 / sqrt ((eff. mass + cart weight + fastener weight) * (compliance))


Example for my Grace 707 tonearm with Grado Reference Platinum cartridge:

Grace 707 Effective Mass Rating: 6.5 grams
Grado cartridge Weight: 6.0 grams
Fastener Weight: 0.5 grams
Grado Dynamic Compliance Rating: 20 (X 10-6cm/Dyne)

(6.5 + 6.0 + 0.5) X 20 = 260

sqrt 260 = 16.125

159 / 16.125 = 9.86 hz calculated Resonant Frequency (which is about dead center within the desired 8-12 Hz range). The Pickering needs to be at least 20 X 10-6cm/Dyne to keep me where I want to be at about 10Hz.

hearingimpared

Greg do you have a test record that tests the resonant frequency of the tonearm/cartridge combo?

inspiredsports

I do have a decent copy of the Shure TTR 115 Era IV "Audio Obstacle Course" which has test bands for 4, 5, 6, 8, 10 and 12 Hz Resonance. Good idea! I can use that.

But I also have my Dad's electrical and mechanical engineering blood in me that make me want to do the math and carry it out to 75 decimal places :D

I'd still love to find someone who knows the Pickering XV-15 1200E's exact dynamic compliance rating.

hearingimpared

I don't know if this helps at all but here you go.

http://www.adelcom.net/PickeringStylus1.htm

http://www.kabusa.com/frameset.htm?/rcleaner.htm