Fozgometer

I have to agree with Doug. Moreover, crosstalk, it seems to me as a layman, cannot be discussed without reference to a level of signal. The Signet Cartridge Analyzer guide advises one to use (any of several possible test LPs) with a 1kHz steady state tone on one channel and nothing on the other. Then you set the Analyzer to receive the recorded signal and set that value to "0db" on its meter. You then set the Analyzer to receive the signal on the ideally negative channel, and the meter shows a value on the negative side of its 0db marking. Thus you can say you have negative X db of crosstalk into the channel that is receiving no intentional signal. Then you repeat the process using another band on the test LP that has signal encoded in the opposite channel. Because you have referenced your result to 0db in both cases, you can say that the level of crosstalk in both channels is equal, or not. And you can discuss magnitude in a meaningful way. Also, as Doug inferred, the results will be very different at different test frequencies. It's usually best around 1kHz and worst at the frequency extremes.

So, I don't know what the quoted part of the Foz manual means exactly, except I guess it would be acceptable to not know the reference level, so long as one did not change the level when comparing crosstalk into channel A with crosstalk into channel B. The signal level, whatever it may be, HAS to remain constant it seems to me, when doing that, if you really want to be able to say you have equal amounts of crosstalk in both channels.

TKetcham, The only other thing in your last post that I would mention is the business about "balance". If you are talking about achieving equal amounts of crosstalk in each channel, then I understand, and I do think that's what you meant. But if you are talking about "channel balance", as in equal gain in both channels, adjusting azimuth is not a way to get there.

Doug, thank you for the clarification regarding channel separation as a surrogate (derivative statistic) for crosstalk. I had used the term crosstalk in the past when describing the Fozgometer but wanted to be consistent with the manual. If you read the manual it does not discuss crosstalk, probably to avoid confusion.

Lew, the test record recommended by Musical Surroundings is produced by Analogue Productions and utilizes a 1kHz tone for the two channels. (They also state that any 1kHz test tone track, one for each channel, can be used.) I have to assume that the two tracks are accurate and equal in output. I have read suggestions to purchase as many as three versions of test LPs to compare tracks and ensure consistency.

I have been curious to use other test tone frequencies to see how the optimum alignment for the 1kHz frequency compares to lower and higher frequencies.

And yes, when I said balanced I was talking about trying to equalize channel separation (crosstalk) between channels. The Fozgometer does have a test for channel output balance as well.

Regards,
Tom

"The Fozgometer does have a test for channel output balance as well."

It would be nice to be able to compare the outputs of the two channels, but do Fosgate imply that it can be equalized via azimuth adjustment?

Lew, no, they do not imply that channel imbalances can be fixed by adjusting azimuth. However, the manual would be much more useful if it included information on how to deal with channel imbalances when adjusting azimuth for optimum channel separation (crosstalk). There are discussions on this topic at several forums but no clear answers as how to best handle it.

Regards,
Tom

Many years ago on Vinyl Asylum, two very knowledgeable guys wrote long treatises on azimuth. At least one of them was an advocate of adjusting for "least crosstalk", rather than "equal crosstalk" (into both channels). Along the way, both stated that one should not attempt to correct for inequality in gain between channels by adjusting azimuth. First of all, even the most extreme differences in azimuth make a very small difference in relative gain between channels. I tried it with my Triplanar and Signet Analyzer; a difference from about +15 degrees to -15 degrees off the 90 degree starting point made barely a 1 db difference in channel balance, and by the way music sounded awful at either extreme. And second, you can't have it both ways; correcting azimuth for crosstalk, as one should do, will not lead also to any significant correction in channel imbalance. So, I guess you're referring to how channel imbalance might contribute to errors in adjusting azimuth for crosstalk. (Yes?) To me, that is no problem if you reference the adjustment to a "0db" point with respect to the channel that is receiving the signal, as I noted above. Don't know about the Foz, but the Signet allows you to do this. You'll still have a channel imbalance, maybe, but crosstalk will be as low as you can get it. The point is that referencing both channels to 0db for the driven channel removes the inequality in gain from the equation, as much as is possible and IMO.