From my perspective I don't see why you would need to go to the frequency domain for azimuth adjustment. The cross talk wave forms tend to be the same frequency as the main waveform and you are interested in minimizing amplitude anyway. I have found that a better test record for Azimuth is "Azimuth Optimizer Test Record" LPT Azimuth 080108. It has 2 sides and both sides alternate 1 kHz recordings on left then right channel. Therefore you can see your cross talk across the entire record. I use a analog oscilloscope Tektronix 475 and adjust azimuth to minimize, and equalize crosstalk. For example: When the right channel has a signal, you look at the amplitude of the waveform in the left channel (crosstalk). When the left channel has a signal, you look at the amplitude of the waveform in the right channel. Adjust azimuth to try and make those 2 amplitudes equal and minimal. So as small as possible and as equal as possible.
You will notice that amplitudes do change slightly as the needle moves across the entire record. What I do is optimize as close as possible to the Lofgren tangent points.
You will notice that amplitudes do change slightly as the needle moves across the entire record. What I do is optimize as close as possible to the Lofgren tangent points.