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[Edit: I am not asking if the Fozgometer works, or if it works well, or if you like how it works. I am asking what principle it works on/with.]I'm trying to get a handle of what this meter does. I know what Azimuth is as well as the difference between crosstalk and separation.
According to the description at Musical Surroundings (I couldn't find Fosgate):
"The FOZGOMETER incorporates a "Log Ratio Detector" developed for surround processor steering logic circuits to measure channel separation over a wide range of signal levels down to -70 dB. The readings are virtually independent of overall signal levels, and can be made with a wide range of input signals without effecting accuracy. . . . It measures channel separation, channel balance, and signal direction quickly and accurately. . . . The meter reads channel separation in both directions, and channel balance. The LED's indicate Left, Center, and Right signal (test tone) positions."
I have downloaded the Fozgometer manual from Musical Surroundings and haven't read it yet. [EDIT: I have now read it. There are instruction for measuring azimuth and what indicates channel balance. They seem to measure the same thing except azimuth measures one channel at a time. There are no instructions for measuring channel separation, only mention that the Fozgometer can measure it.]
Here is my question, as the owner adjusts the tilt (azimuth) of the cartridge in the smallest angle possible what is being read by the Fozgometer? Is it inverting one channel and adding to the other to obtain near zero output?
If not, what is it doing?
And the second question. I had read it came with a test LP, Musical Surroundings seems to sell The Ultimate Analogue Test LP as a tool for the Fozgometer. Was I wrong about it coming complete (with LP)?
Thanks in advance to all serious replies.
Remember, YOU are the only one who needs to be happy with the sound of your system
Grainger Morrison
There Is Only One (Grainger Morrison, it seems)
Edits: 03/06/11 03/06/11 03/06/11Follow Ups:
Hi, Grainger,
Your question (how does it work?) has been asked many times on many forums and you won't find a definitive answer to that question on any of them. The reviews have been just as evasive, providing only the standard advertisement copy found on Musical Surroundings website. It's apparent that whatever Mr. Fosgate uses for programming logic in the Fozgometer isn't going to be divulged anytime soon by Mr. Fosgate or Musical Surroundings. I suppose that someone could "reverse engineer" the unit to find out, but so far noone has done so. Or at least noone has published such findings.
You'll just have to try one. Or not.
Regards,
Tom
Mostly I have been trolling Bottlehead and AK. No offense meant to the Asylum at all. How are you?The manual exposes some of the functioning when measuring channel balance. It subtracts one channel from the other to read zero. And as John Elison has said in a number of threads about the Fozgometer it doesn't take any channel imbalance into account.
Its use is a little awkward in my opinion. You have to "measure" crosstalk by comparing one channel to the other one at a time not both at the same time.
You measure channel imbalance by playing a mono (both channels) selection and if it doesn't read zero you have an imbalance.
There are no instructions or even any indication that the imbalance should be taken into consideration when attempting azimuth adjustment.
For my $300, including test LP, shipping and tax, I will use my Tektronix oscilloscope instead. I can adjust for any channel imbalance with it. And I already have it, no cost here. I can spend more on vinyl.
Remember, YOU are the only one who needs to be happy with the sound of your system
Grainger Morrison
There Is Only One (Grainger Morrison, it seems)
Edits: 03/07/11
Hi, Grainger,
The comments I've read thus far do seem to indicate that the Fozgometer works very well with cartridges that are within a certain level of channel output tolerances. I'm fortunate in that the three cartridges I've aligned using a Fozgometer have had essentially zero channel imbalance with very good stylus alignment (attachment) and so azimuth adjustments were quick, easy, and accurate.
But it would be helpful if Mr. Fosgate and Musical Surroundings provided at least a basic explanation of the inner workings of the Fozgometer. And given that each channel of the Fozgometer can be calibrated separately, I wonder if there might be a way to check for channel imbalance and then use the calibration feature to accomodate cartridges with poor channel separation tolerances.
Regards,
Tom
This device seems to be able to accept inputs from line level to HOMC cartridges. The range indicated by the manual is 40dB.As John Elison mentions the crosstalk is the key and the Fozgometer doesn't measure that well. Making that "measurement" is very awkward.
Michael Fremer's response to this is that if you pay for a good cartridge it should have matched outputs from each channel and matched crosstalk.
Nice if you pay above a killo-buck for your cartridges but what about usnormal guys?
Remember, YOU are the only one who needs to be happy with the sound of your system
Grainger Morrison
There Is Only One (Grainger Morrison, it seems)
Edits: 03/08/11
I own a Fozgometer and have been happy with the simpilicty of the tool. My cartridge is .3 output and I have been using the phonostage output for measurements. If I use the phonocable direct, would I need to ground the cable as I would with the phonostage, or would this affect the readings if not grounded.
Taylor,
Good, but that wasn't the question.
I read the manual and it doesn't answer me eiter. But it states, "Tonearm cables connected directly to the Fozgometer may require the turntable ground wire to be connected to one of the meter input jacks to prevent hum pickup."
That should answer your question.
Remember, YOU are the only one who needs to be happy with the sound of your system
Grainger Morrison
There Is Only One (Grainger Morrison, it seems)
thanks Grainger ... I do realize that it was not "the question", just looking for comments from other owners. That said, "may require" is a vague instruction from the manual, don't you agree. I tried contacting the company for a more definitive answer but the e-mail address does not seem to work. Thanks.
I would just try it both ways.If you get an indication of signal with the arm up you will probably be looking at noise, most likely hum.
According to the manual "each meter division is approx 1 db. The meter will read zero if the channels are balanced." This says that one channel is being subtracted from the other. Any imbalance is read in "db" and the higher channel is indicated by the LED.
If it subtracts one channel from the other and the hum is equal in both channels you might read zero. I.E. 1 -1 = 0. In this case try one arm lead at a time to see if either has noise, any reading on the Fozgometer without the stylus on the LP. Just attach the TT ground wire to the other channel outer conductor and see if the meter reads lower.
Remember, YOU are the only one who needs to be happy with the sound of your system
Grainger Morrison
There Is Only One (Grainger Morrison, it seems)
Edits: 03/06/11
taylor, you shouldn't need to ground the cable. btw, i use the meter with a benz ebony lp, .34 mv output, and it works fine, no need to take the higher voltage signal from the phono stage.
That's good to know ... thanks for both of your suggestions. This is a very worthy tool IMO.
The test record is sold separately. With it (or something like it), the Fozgometer is supremely easy to use. I have no idea what it measures or how it works and don't especially care. It definitely does the job, and having the azimuth near-perfect is quite beneficial in terms of openness, soundstaging, dynamics, etc. It's difficult, however, to do a before and after comparison, although I suppose you could record an LP onto a topflight stand-alone CD recorder before and after making the adjustment.
I was just glad that my arm (JMW 10.5i) makes it easy to control and readjust azimuth, unlike my friend with an SME V.
Dave, thank you. I had misread the review in Stereophyle thinking that the Fozgometer came ready to go. It seems to me that they are putting their trust in the test record mastering and pressing. [Edit: My arm is a PITA to adjust, moving a little is next to impossible and can put the VTF off. But you have a nicer, more expensive arm than my old Souther.]I read the manual while you were posting. Groan, it could be much better....
It reads that you play a modulated right channel signal, the left quiet, and "observe the meter reading". It would be signal strength in dB increments but doesn't give the reference (as is required for a dB measurement). Then play a second groove (assuming the same modulation) where the left groove is modulated and the right quiet. Rotate the cartridge according to the instructions and try again till you get matched outputs or the best you can achieve.
This seems to balance the output of the cartridge if you take the signal from the arm, or in the case of taking the signal from a phono stage it balances the output of the cartridge and phono stage, or in the case of taking the signal from a record output it balances the output of the cartridge and phono stage and the buffer to the record output.
I could be wrong. But I'm looking for an explanation of what is going on here.
I would just take my cartridge leads, invert one channel and combine the output at the end of the arm leads. Then I can play a test tone that was purely mono and observe the output on my oscilloscope. Since the channels are inverted, subtracting one from the other, the minimum reading on the oscilloscope would be best azimuth setting.
Please if anyone knows more about this device help me understand it.
Remember, YOU are the only one who needs to be happy with the sound of your system
Grainger Morrison
There Is Only One (Grainger Morrison, it seems)
Edits: 03/06/11
Gee, your approach sure doesn't sound like much fun :-)
One of the joys of being a near-total technical illiterate is not having to obsess over such things. If it works, it works. And it sure does.
Clearly, different strokes.
Dave
That's true, but how does one cope with the dire existential angst over the lack of a Fozgometer ;-)
Regards Ferd
... by buying a Fozgometer.Actually, I just waited until one showed up on Audiogon.
Edits: 03/06/11
It is fun for me in that I have the 'scope, and it measures one channel versus the other all at one time. Inverting and adding are buttons on the scope, it is on most scopes.
Remember, YOU are the only one who needs to be happy with the sound of your system
Grainger Morrison
There Is Only One (Grainger Morrison, it seems)
Edits: 03/06/11
I second that, I don't own one but a friend does. My ears tell me it does the job very well. Highly recommended!
We are not understanding the question here. I am not asking if it works, but how it works.If I find the principles behind it, and appreciate them, I would invest in it.
Remember, YOU are the only one who needs to be happy with the sound of your system
Grainger Morrison
There Is Only One (Grainger Morrison, it seems)
Edits: 03/06/11
nt
If that is his Moniker I can PM him. Is that his Moniker?I sent him an email through the Asylum. He responded and we are in deep conversation.
Thanks for the reference.
Remember, YOU are the only one who needs to be happy with the sound of your system
Grainger Morrison
There Is Only One (Grainger Morrison, it seems)
Edits: 03/06/11 03/07/11
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