Many of the old singers had consistent pitch. I was interested in the change in quality of Phil Tanner's voice between 1937 (age 75) and 1948 (age 86) and a while ago I listened a few times to his two recordings of Sweet Primroses. The pitch seemed to be the same in both recordings and I switched from one to the other after the first verse. They were at identical pitch.

Re the singing of intervals, I notice that Phil often dropped too far on wide intervals, ie, he landed slightly flat. The following note was pitched correctly. In general, he sang near the top of his range, and breathed much more often than most singers - maybe his age when he recorded?

I don't usually have a problem in maintaining unaccompanied pitch, which I've usually put down to only using 2 or 3 keys on the guitar. My comfortable low note is G, and I can usually pitch that fairly accurately. I sing a lot in G, and seem to be able to hear the GBD in my head while I'm singing, which gives me a framework to keep pitch.

The main problem is when I follow someone who plays or sings in unrelated keys. I need a couple of lines hummed to myself to clear my mind of the previous key.

Phil