Warm up time for record playing

@thecarpathian, not a bad idea but unfortunately not necessarily true. You have to factor in expectation bias. In order to determine if one item sounds better than another you have to be able to switch back and forth. You can only pay attention to one item at a time. You can not evaluate the bass and the treble synchronously. Your brain switches between the two. It helps further if you do not know which one you are listening to. Expectation bias is very real. Magicians use it all the time along with the power of suggestion. 

My phono stage: on, always (as suggested by it’s creator).     TT and SDS: turned on/spinning at least 30 minutes before listening (for bearing lube, belt, whatever).        While warming up my ears, in anticipation of realistic SPLs (as mentioned above) and expecting my cartridge suspension to limber up, during the first two or three cuts; I’ll do a crossword or sudoku.      Unless pondering CD pits and digits, previously, I figure the rest of the system is still warming up/stabilizing, as well (lots of tubes).     The realism manifests, when everything’s warmed/turned up.     The second vinyl typically takes me, "there", better than the first.

**** Why do you think they have warm up bands at concerts! ****

I was not doubting your comments about physiology at all and I made that clear; only the degree to which it might be a factor. You lost me with this one, ‘though. I seriously doubt concert promoters are concerned with the “physiology of hearing“ other than the deluded notion prevalent these days that louder is always better. Building anticipation, giving the audience their money’s worth, or even setting a lower (not always) bar for the main act with a warm up band?  Sure. However, I have known a few and not once has the issue come up. Moreover, where’s the physiological “warming up” when attending a live orchestral concert, for instance? Does the third movement of a symphony always sound (!) better than the first. Not a chance.

I’m glad to hear all the corroborating responses to my observations.
As is said above, It’s not mutually exclusive that physiology and warm up time are both possibilities.

@frogman I think you've got it right, music needs to play through to "warm" everything up and 2 sides of an LP seem about right to me for getting up to proper listening speed, i have the same experience with a Musical Fidelity A5 CDP ....its like partway through the first CD of a session it sounds so much better ..