Speakers sound brighter at evening / night?

Do not have this problem however were i live we have or own power plant.

Things sound better at night, not brighter.  Brighter ≠ better.

It just occurred to me how we could perhaps test this idea. I see a lot of youtube videos of people's high end systems playing. You get to hear their system, sort of. It's obviously a  flawed method, but it can tell you some important things like bass response and overall room sound. If the music sounds clean and natural in a recording like that you know that the system has to be working pretty darn well. With that in mind, might it be possible to catch the difference in sound by recording in the daytime and then with everything set exactly the same record again at night? Any major changes in the sound should be picked up by the recordings. 

"What is it with this urge to explain away the things we hear? Not explain- explain away. The implication is you didn't really hear what you know perfectly darn well you did. It didn't really happen. You only think that it did.

Poppycock! "

millercarbon, I firmly believe from my own experience that there can be profound differences in perception of the same sound at different times due to the state of mind of the listener. Some people, perhaps yourself, may be better at purely objective listening than others. I know my limits and have to be careful. Flying an airplane in clouds taught me really quickly that my inner ear sense of up and down is not well fixed, but is highly calibrated by what my eyes are seeing and what the rest of my body is feeling. I've experienced my sense of timbral balance change significantly at times. I came home one time after a long drive and turned on my system. The bass was severely lacking. I measured. It measured just fine. I listened to the same music on my headphones using an entirely different battery operated playback chain and the bass still sounded thin. It had to be my perception being temporarily altered, not the equipment output changing. 

Why is that surprising?  Food tastes better/(ok--different) in the evening.  Sex is better/different.  Drugs are better/(different).  Falling asleep is different.  Having a phone conversation is different.  Why shouldn't music sound better/(different)?