How to measure crosstalk


Can anyone explain to me how to measure crosstalk using a multimeter for setting azimuth?
jsman

Showing 3 responses by dougdeacon

Great explanation by Tim. One addition: you need a notch filter to reduce frequencies above/below the test tone. Otherwise, at the tiny levels we're trying to adjust for, background surface noise from the vinyl will swamp the results at the meter.

Wally's device includes this, or you could DIY your own.
Sorry for the inaccurate term. My electronics skills are easily a match for yours, Pryso. ;-)

At least I knew what I meant, and fortunately Rene did too!

Doug

P.S. Paul and I are among those annoying guys that Tim mentioned in his excellent post. After using the Wally Analog Shop (which works great) to adjust azimuth on several cartridges, we learned we could get just about as close by listening. Our main cartridge goes below the resolution of our multi-meter, which worked out to < 0.1db crosstalk. When azimuth's correct L/R images are so tight they're almost invisible. ;-) Less fiddling time and more music time works for us now, but it was useful to be able to measure and confirm what we were hearing.
Pryso,

You have to be in the sweet spot to fine tune azimuth by ear. That's the only place you can hear your sytem's L/R imaging at its best.

Don't use test tones to set azimuth by ear. They wouldn't help. Use music, preferably higher pitched instruments and/or vocals. Our ears are more sensitive to directional cues at high frequencies.

Don't use rock, use well recorded acoustic jazz or classical. (Who cares about azimuth for rock anyway? Oops! There I go!!)

It's best to rough azimuth in by eye first by making your stylus as close to vertical as possible. No matter what your meter or ears tell you, you don't want your stylus significantly off vertical - for the sake of your records and your stylus. If you have to angle it more than 1-2 degrees something's wrong (probably with the cartridge, few are perfect).

Before attempting to fine tune azimuth any more closely, make sure all of the following have been done:

1. your cartridge is well broken in

2. VTF is optimal (set by ear, not just by what some scale reads; if you can't set VTF by ear you certainly won't be able to do so with azimuth)

3. Antiskating is optimal (set by ear, not by what some dial reads; ditto for needing to be able to do this by ear before attempting azimuth)

4. the system and cartridge are warmed up, play 2-3 sides before you begin.

I can't describe what to listen for any better than Jtimothya did:
Listen to a female vocalist who sings center stage. Adjust azimuth to get her mouth/voice as small/narrow as you can. Incorrect azimuth tends to splay sounds horizontally, making instruments and voices larger (spread wider) than they will be when azimuth is correct.
When you think about what crosstalk does to a stereo image, you realize that's a perfect description.