Is tonearm bias a compromise, maybe a myth?


I recently decided to check my tonearm/cartridge setup: alignment protractor, tracking force gauge, checked VTA, bias weight, etc. as over my many years with turntables and tonearms I have been surprised to discover that "shift happens". I have a very low mass arm with a very high compliance MM tracking at 1.25 gms. There was just a minor shift this time in tracking force. But afterwards I was really surprised at how much more depth there was to the soundstage and greater subtle details. I was then gobsmacked by the discovery that I had forgotten to re-attach the bias weight thread! Applying Lateral Bias seems to compromise performance elsewhere, true?
elunkenheimer
Amount of AS is necessarily a compromise, but with a pivot type arm there's going to be skating. Amount of skating depends on more than just VTF. It increases with stylus velocity and steeper offset angle. It is caused by offset angle - the plane of the cantilever is extended off to the side, rather than aimed at the pivot as in a linear type arm.
So set your AS for "normal" loudness of most of your listening fare, not highest velocity on a test record. Offset increases as the stylus nears the center of record. Too little AS could add to inner groove distortion. Amount of AS is a compromise, but not a myth. Channel imbalance is readily seen on a scope or with newer software available. Carts with long cantilevers - skating can be observed visually if viewed from directly in front of cart while playing. Either the cantilever is almost centered relative to the body, or it's off to one side or the other.
What Fleib and Audiofeil said. But I'd rather do this topic again than Madonna.