Velvet Underground LP grooving issue

Hi

Reading the Velvet Underground thread reminded me of my (reissue) copy of The Velvet Underground & Nico, which has a singular (to me) groove configuration towards the end of side 1.

You know how you can look at an LP under a light and 'tell' by the reflection on the grooves which are the 'denser' (ie. louder) tracks and which are the softer ones?

This LP looks like it 'shifts' from one groove spacing (or whatever it is) to another right in the middle of a song, yet there are changes in the sound.

I'm assuming this is something whoever cut the LP did in order to fight end-of-side distortion, but what is it?

Just curious, .. posted this here so as not to 'pollute' the ongoing VU thread.

Damián

 

Sometimes cutting engineers have been known to turn off the groove computer in mid side, or just increase the spacing, so that the dead wax isn't too big. Apparently (pure speculation on my part) on the theory that you don't want the people to think they are getting short-playing sides.

On the other hand sometimes groove spacing is intentionally widened to keep pre/post echoes from occurring, if there are wide dynamic contrasts.

In the early 1970's there were a bunch of Phillips classical LPs where suddenly there'd be a wide groove here or there for no apparent reason at all. I don't know if there was a bug in their machine or what. (It wasn't for pre/post echo prevention; it seemed totally random.)