DISCUSSION: "It only comes out at night". Does anyone else have this experience!?

For sure ambient noise levels lower for many, typically in mid 40's db during day, can get down to mid 20's late at night. The dark also adds to sense of realism, I have black out shades over all windows, also helps to block out external ambient noise. Electric grid is of lesser importance as I use power conditioning.

Those who've mentioned snow are on to something, snow is insulator. I have crawl space under house,  snow piled up around house, storms on windows down, very little traffic due to snow, no wind, night. This is the absolute very best ambient noise situation for me. The greater dynamic range recordings are most affected by ambient noise floor, quiet passages are absolutely ruined during day, the amount of low level info heard during these quiet passages makes all the difference. Classical music comes alive for me, can't hear all the nuance during high ambient noise times. If one only listens to loudness wars, no dynamic range recordings doesn't make any difference. I have neighbor only listens during day, heavy metal all the time, likely over 100db in his room, ambient noise sure doesn't bother him!

I  supply part of  my system with lithium ion battery pack that puts out pure sine wave. Using on dac compared with AC fed from modded BPT 3.5 transformer based conditioner, I prefer feed from BPT, slightly more closed in veiled sq with batteries.

My take is the inverters in these products affect sq to some extent, YMMV.