faint precession of sound on vinyl

I used to think this was a problem with my cartridge alignment or tracking error of some sort. It seemed like when I switched to the 10.5i arm from the 9 sig it decreased. Maybe it only seemed that way. Thanks for the explanations on something I've always wondered about.

Print though on tape is the reason they are stored tails out.

Rwwear...I didn't know that. Can you explain how this helps.

If it was the stylus reading the signal on the adjacent wall wouldn't it change channels? I notice it is always on the same channel it is preceding.

I am just going to go back to what I have done since I was 9: ignoring it.