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

Oh, there is no doubt speakers have to warm up. Both the VC and the surround. It is most obvious to me in my Jeep. First thing in the morning my sub seems basically non-existent. After driving for a bit, ambient temps go up, woofer warms up, BIG difference. 
 

I am a Replicant.

The car at night - Its cooler at night , therefore more oxygen molecules available for combustion . Result more power . Of course turbo charged cars will benefit even more.

Hi-Fi at night. Electro-Magnetic radiation from the sun is shielded by the earth during the night.EM is a known audio noise , that has significant effect on SQ.

I don't buy the AC supply being quieter at night in  a normal residential environment . 

once I lived in a house with such a horrible electrification, that I could only listen to music after midnight.

I highly reccomend to buy a AC iPurifier. It will sound much better!

A simple environmental factor-darkness or a lack of light plays a significant roll to sharpen our hearing.  This simple factor allows our brain to decrease visual processing and devote more focused cerebral attention to our hearing.

One would believe that the power grid may be cleaner at night but difficult to quantify.

For whatever the reason(s), my current system sounds much better at night.  I first  noticed this back in the 80's when I was stationed in Munich Germany.  I'd get off work and turn on my all SS system (Pioneer SPEC-4 power amp, SoundCraftsman EQ/Pre, Teac X-10R R2R, dbix 224 and dbx 3BX, Technics SL-1200, and Bose 901's).  After about 3 or 4 hours, the R2R sound would be so sweet.  At the time, I had no clue about warm-up time.

Now it takes about 30 minutes for my PS Audio stack to warm up and the SQ is really good.  Later in the evening, the SQ goes to another level.