How to measure crosstalk

Sorry guys, you've confused me.
Dougdeacon calls for a notch filter above/below the test tone.
Restock agrees, but suggests a 1KHz bandpass filter.
I'm showing my electronics ignorance here but what filtering point(s) is/are needed for a 1K test tone? Is there a source for plans to build this filter?
Thanx.

A different question for Doug and others who set azimuth by ear - can this be done by one person while listening off center? My tt is on a side wall, well outside the nearest speaker. I've never tried listening to a test tone for azimuth since it would mean running back and forth between the tt and my listening seat.

Also, thanks Rene and Doug for your quick clarification.

Doug, good stuff, very helpful. I always assumed judging azimuth correction would require listening from the sweet spot but never tried it. My cartridge set ups have been limited to a close visual check for front vertical alignment of the stylus.

This whole series of posts has been informative so thanks too to Jsman for starting it off.