How to read a compliance formula

[arcamguy1]

Hi group,
I'm looking for a lower compliance cartridge, and I'm currently looking at a Denon DL103r.
I don't understand how to interpret the stat: 5x10-6cm/dyne
Does this mean the compliance is 5? Also, being a Japanese cartridge, I understand you need to multiply to number by 1.75 to get a proper reading.

Also, which compliance stat is important: static, or dynamic?

Appreciate any guidance. Thanks,
Jeff

 

[Blue Shadow]

You need to know that the compliance was tested at 100Hz instead of the standard of 10Hz to use any multiply by number. That number being somewhere between 1.5 and 2.0 so 1.75 is fine. 5 would be the cu of that cartridge. I would think the dynamic compliance would be the one to work with as the stylus is always moving and that is dynamic.

You are using the VE database and resonance calculator, aren't you?

 

[lini]

Jeff: Compliance basically is reversed (spring) stiffness, i.e. displacement per force instead of force per displacement. Typical range for hifi cartridges is about 10 to 50 µm/mN - but of course one could also write that as mm/N or m/kN, which would be easy conversions (numerator / 1000 and denominator / 1000 each, so we can scratch/reduce that). However, you could also convert to less easily applicable unit variants - like for example cm/N, so that we'd need an additional "x 10^-1" as correction factor, if we'd still like to state that same range as 10 to 50 (x 10^-1 cm/N). Well, and the dyne is a pretty small unit of force (1 N = 100000 dyn) - so if we'd start at our equivalent 10 to 50 mm/N, we'd need numerator / 10 and denominator x 10^5 = numerator x 10^-6 to arrive at our desired 10 to 50 x 10^-6 cm/dyn.

So that's merely a bit of conversion math in order to present nicely readable values. And because both of the usual styles, yy µm/mN and yy x 10^-6 cm/dyn, describe just the same range, the lazier among us phono fans have adpoted the "cu" for "compliance unit(s)" as conveniently typable "replacement (pseudo-)unit".

Well, and both (or maybe even all three, if we regard Japan style dynamic compliance @ 100 Hz as somewhat different matter compared to dynamic compliance @ 10 Hz) types of compliances can be useful. The type of compliance you need for working with the usual tonearm resonance formula is the dynamic compliance at 10 Hz, though.

Greetings from Munich!

Manfred / lini

 

[tnsilver]

Wow lini! That's the coolest compliance unit explanation I had ever seen on line.

Just my two bits for the OP here... Japanese compliance standard. like mentioned by Blue Shadow,
is taken at 100Hz.

Springiness is a function of frequency, so we have to compare apples to apples here, and unfortunately, the US/European standard, the same standard VE calculators refer to, is dynamic compliance at 10Hz. We cannot infer compliance data at 100Hz to calculators that use 10Hz.

Another interesting thing is that static compliance, when it comes to styli compliance, is meaningless.
In fact, on the rare occasions when static compliance is mentioned by the manufacturer, you can rest
assure there's some marketing bamboozling scheme behind it. It's crap! No engineer would state a stylus compliance measurement in static units. Adding insult to injury, the multiplication factor of anything between 1.5 and 2.0 to convert compliance at 100Hz to compliance at 10Hz, refers to static compliance (meaningless, as mentioned earlier).

In fact, there's absolutely no conversion formula between compliance taken at 100Hz and compliance at 10Hz. That's sad - but true. The little light that shines in this dim tunnel, are reverse engineering measurements taken by the good people of the on-line audio community. Enthusiasts around the globe measure the resonant frequency of their carts using test records, and knowing in advance their tonearm effective mass + cartridge and fasteners mass, they can calculate (using the same VE calculators for instance, or just doing the plain old math) the compliance at 10Hz.

So if you need an initial preliminary assessment of the compliance of your stylus and all you got is the stated Japanese measurements, look on line or do the math after testing for the resonant frequency with a test record. YMMV, but you'd come close to the compliance at 10Hz.

 

[lini]

Tom: I wouldn't concur that static compliance is useless. For example, along with tracking force it can serve as an indicator, whether a given, but not precisely specified dynamic compliance will more likely be a 10 Hz or a 100 Hz value. Then it can also be useful as an indicator, whether the cantilever suspension is still ok - or to get a good estimation on how much of an SRA/VTA fine tuning range one will have at hand via tuning the VTF within reasonable limits.

Greetings from Munich!

Manfred / lini

 

[tabarddn51]

For my 2 cents worth, Use the charts as a guide only, it is only an indicator & it is what the cart sounds like in your system, is the most important thing.
Yes the 103 will play in arm with a medium E/Mass. However the vast majority of listeners concur that it sounds better in a high mass arm, in a medium mass arm it looses bass impact.
I always try for a resonant frequency of around 9.5 to 11hz with my arm/cart combinations. (this seems to suit my system, others may be different) So if we for arguments sake take the middle ground & use 1.75 as the conversion factor, then the standard 103 requires a Eff Mass arm 29 grams (that's cart/arm/screws) to hit 10hz. Lower R/freq would need a heavier E/Mass & a higher R/freq then a lighter arm can be used. But it is not advisable, (as I understand it to go above 12 or so gets to near bass & rumble frequencies). This means theoretically the cart could be used with an arm with an E/Mass of 12, but it is not advisable.

Cheers