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So I ordered a Ortofon Quintet Bronze LOMC cartridge, 15um/mn lateral dynamic compliance, 9gms. weight. I want to mount it to a Ortofon SH-4 headshell 9.4 gms. mounted to a Fidelity Research FR-54 tonearm with an effective mass of 16gms. Would this be a good combination compliance wise? Thanks
You asked for it....
The aim is to keep the resonance well above possible warp frequencies of a disk, and well below any possible low audio frequency engraved on the disk. The limits are commonly given as between about 7 Hz and 12 Hz. Thus John's calculation leaves you in safe territory. One of the Shure test records (Era V, I think--perhaps others) provides a test revealing a cartridge/arm's actual resonance.
I would not say that 8 Hz is "well above" the warp frequencies. There is no sharp cut-off and if you are higher, e.g. 12-13 Hz, you will allow for a better tracking of the grooves. See example above with resonance of about 8 Hz. A warp at 6 Hz will just be -7 dB down in level.
I agree! Normally 8-Hz is considered the lowest desirable arm/cartridge resonance frequency. However, it also depends on other aspects such as the amount of cantilever damping and also the amount of tonearm damping. For example, my AT-ART7 cartridge exhibits an arm/cartridge resonance frequency in the neighborhood of 6.5 to 7-Hz in my SME V yet it plays well and sounds exceptionally nice on my Sota Millennia turntable, which incorporates a vacuum platter.
I would prefer its resonance frequency to be 10-Hz, but Audio Technica apparently raised compliance without notification. The ART7 is specified to have dynamic compliance of 10 x 10 -6 cm/dyne and the ART9 is specified at 18 x 10 -6 cm/dyne, but Audio Technica seems to have made them both with the same high-compliance.
I just feel fortunate that my ART7 still works well and sounds good with such a low arm/cartridge resonance frequency. I think it might sound better with lower compliance, but such is life! It still sound better than my Denon DL-S1, which exhibits an arm/cartridge resonance frequency of about 8.6-Hz.
I have written it before but I think it is strange that most combinations today are on the low side of 10 Hz. Even if they sound fine at 8 Hz, they will sound even better at 10 or 12 Hz. The stylus will deflect less due to warps and record imperfections which will improve channel balance and stability of tracking force.
You are correct. What the Shure V15 type V test recording says is: "When the arm cartridge resonance is close to record warp frequencies (typically from 0.5 to 8 Hz), the presence of such warps will cause . . ." As far as I know, that was their last word on the subject. I have, though, seen other figures from other sources.
Just because the headshell is .5 gram heavier doesn't mean eff. mass is increased by the same unless it's directly over the stylus
I used a decrease in effective mass of 0.5-grams, but I probably should not have done that. The original headshell weighs 9.9-grams and the Ortofon headshell weighs 0.5-grams less at 9.4-grams. If we keep tonearm effective mass exactly the same at 16-grams while using 9-grams for cartridge mass and 1-gram for mounting hardware, the arm/cartridge resonance frequency will be 8.06-Hz instead of 8.14-Hz.
I think the cartridge should still probably work okay.
Thanks for the info guys, I appreciate it. Calculating resonance just is not my thing....
As Tre' points out, the headshell is included in the 16-grams effective mass. Therefore, when using the Ortofon headshell you can subtract about one-half gram from that figure making effective mass about 15.5-grams. Since Ortofon specifies compliance at 10-Hz, the arm/cartridge resonance should be about 8.14-Hz when allowing one-gram for cartridge mounting hardware. I think the Ortofon Quintet Bronze should be a good match.
If the Ortofon head shell is lighter than the original head shell then the effective tonearm mass will be lower (by about the difference in the head shell weights).
Edit, I found a website that says the original head shell is 9.9gr
Using the lighter head shell should help get the resonance up a little with your set up.
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