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In Reply to: RE: Frequency range: 20Hz - 70 kHz. What's the point of........ posted by neobop on September 19, 2014 at 20:54:20
> Hagerman isn't posting misinformationIf Hagerman isn't posting misinformation, then neither am I. You can't have it both ways. Sorry!
Better luck next time, although I hope there isn't a next time.
Goodbye,
John Elison
Edits: 09/19/14Follow Ups:
**If Hagerman isn't posting misinformation, then neither am I. You can't have it both ways. Sorry!**
Hagerman's electrical resonance model is valid only in the electrical realm. It's useless for loading purposes because it ignores the mechanical aspect. Your Hagerman extension makes the same mistake. Here's what Werner (the same Werner who wrote the TNT article Load the Magnets) had to say about the Hagerman calculator and a Spice loading program differences:
folkdeath95 wrote:
**Hello,
The Spice simulation program that CarlosFM used, seems to differ somewhat from the Hagtech results.**
Werner wrote:
**And both are near-useless as they don't take the (inevitable) cartridge's mechanical resonance and treble losses into account. With MMs this is all happening around 10-20kHz, and electrical resonance (through loading) is used to compensate for this.
Mechanical resonances and mechanical treble losses (how fast can you wiggle a given mass?) don't show up in electrical models of cartridges. Both phenomena happen between 10 and 20kHz with MM cartridges.
Sadly cartridge manufacturers don't publish the electrical equivalents
of their products mechanical properties.**
I don't expect you to accept Ortofon's MEASURED phase response. I offered to email the PDF to you and I got no response. I post this once again for those interested in this subject.
Regards,
BIRD LIVES
> Hagerman's electrical resonance model is valid only in the electrical realm.
You are absolutely right. My model is valid only in the electrical realm, too. I've been trying to tell you that for years. However, the thing that matters is that high inductance cartridge have their electrical resonance within the audible range between 10-kHz and 20-kHz, and this causes audible problems regardless of how their cantilever mechanical resonance interacts. Low inductance moving coils do not have an electrical resonance to contend with until you get into the megahertz region. Consequently, their cantilever mechanical resonance can be dealt with by using stiffer cantilevers to move it out of the audible frequency range. The mechanical cantilever resonance of the Dynavector 17D3 is 80-kHz, which removes if from audible frequencies. In fact, just about all moving coil cartridges have their mechanical cantilever resonance well above 20-kHz so it does not fall into the audible range. The reason that low-output moving coils have a rising frequency response in the high frequencies is because their mechanical cantilever resonance is purposely under-damped in order to reduce phase shift within the audible range. Ortofon was able to manufacture moving coils that exhibited very little phase shift within the audible frequency range by under-damping the cantilever mechanical resonance and moving the electrical resonance out beyond 1-MHz. This is what makes low-output moving coils sound better than high-inductance moving magnets.
Goodbye again,
John Elison
PS. There will be absolutely no difference between a Spice analysis of Hagerman's electrical model and my electrical analysis. As long as you use the same electrical model, there can be no difference unless Spice is designed incorrectly, and I seriously doubt that is the case.
** My model is valid only in the electrical realm, too.**
But it isn't. In the case of a cartridge with almost no inductance (LOMC), phase shift is defined completely by mechanical properties, not electrical. This is clearly shown by Ortofon, but you refuse to look at it. An undamped MC200 w/boron cantilever has primary phase shift occurring at 27KHz not somewhere in the stratosphere.
> Typically, the undamped moving coil cartridge has response which begins to rise in the 5 to 6KHz region, climbs to + 8dB at 20KHz, and peaks at about 15 to 18dB at 25 to 28KHz. This undamped cartridge also has a large amount of phase shift, up to 180° centered around the resonant frequency. <
Regards,
BIRD LIVES
> But it isn't.
It has to be; it's not really my model; it's Hagerman's model. I copied it. Go bother Jim Hagerman and leave me alone.
Good riddance,
John Elison
What are those audible problems? I asked earlier and you apparently thought I was being argumentative. I wasn't, it was simply a serious question. I'd like to know what the aural/audible manifestations of the phase shift you're talking about are.
Phase shift is a time distortion and it varies with frequency. In this case the distortion is plus. As it's plotted, it peaks at high frequency resonance where the shift approaches 180°. The shift diminishes on either side of that peak and will eventually go to zero.
Ortofon used their MC200 as an example, saying that undamped it had spectacular imaging, but was unlistenable due to excessive brightness. Damping was required and imaging suffered the more damping was applied.
This analysis is looked on with some suspicion. It could be the rising amplitude response that caused the spectacular imaging or a combination of those two. Imaging is the only aspect of performance alluded to.
neo
BIRD LIVES
I don't hear timing issues with my mm's, all of which have pretty good imaging. I'm more concerned about realistic timbre anyway, and if there's an effect on timbre due to phase issues that my carts have I'm not hearing it. 'Course my whole system is far from SOTA.
Edits: 09/20/14
I'm keeping it secret. The only way you'll ever know is to make your own comparison.
Good Riddance,
John Elison
nt
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