Using test record bands for lateral and vertical cuts?

I've had a Dual 704 that was sitting unused most of the time. I had attached a Shure M97xE cart to it and I recall using the protractor originally, but the few times I turned it on over the past two years, I just checked tonearm balance and set about playing the record. I wanted to needledrop a few LPs and consequently became obsessed with getting the alignment as perfect as I could for the first time. I have always approached this turntable from a budget perspective. I have tried to do what I could without expensive tools, like a modern test record. I did have a Vanguard Stereolab test record I picked up once for $4 that I could use to get at least some perspective on measurements. Of course, the disc has some spots with groove damage from mistracking and there is some dirt that just seems to be baked in, but I gave it a good scrub and vacuum to get a bit more life out of it.

From the Stereolab test record, I used tones on the left and right channels to adjust for azimuth. I started with a lot of crosstalk from the right channel, but got that down to an even level across the left and right. When I did this, I noticed a band on the record that included test tones cut laterally followed by tones cut vertically. The narration said the levels should be the same, but they never were. When I started, the first tone (lateral cut) balanced well between the left and right, however the second tone was lower and more distinct on the left channel. Once I had azimuth and overhang set where I wanted, I played those lateral/vertical tones again and noticed the vertical cut tones were more balanced between left and right, however they never played at the same volume level as the first tone. I have attached a screen grab that shows the waveforms of these tones so you can get an idea what I'm talking about.

Based on the understanding that lateral and vertical cuts combined create stereo audio, I surmised that these tones should help adjust something, I just could not determine what that was. Internet searches and brief forum searches turned up no direct references to using test records with these tones. I had hypothesized that dialing in azimuth, overhang, tracking angle and anti-skate force would make both test tones even in level, but that is not what happened.

I am actually very happy with how things sound after my adjustments, but I wanted to be sure I didn't overlook any possibilities.

 

Ah well, I guess my mind wraps around things most people have little interest in. Thought this morning I should have titled my post "Fun with test records!" to sound more interesting.

I have had fun learning to align my cartridge the right way, though.

 

if the tones are of different frequency I think that what you are seeing is basically the deviation in frequency response of the cartridge at this tones, it should be linear across the audio band but no cartridge is perfect also the response is always a little different between the two channels, the response of your "audio chain" will make an impact.

 

Lateral modulation is the mid (mono) signal, vertical contains the side (stereo) info, so it stands to reason that the latter are better matched after adjusting azimuth/crosstalk. Maybe in the ideal scenario of zero crosstalk, the lateral and vertical signals would be equal.