I’m sure this this has been covered here before but I thought it would be of interest since we all seem to experience it. Often our systems sound better at certain times of the day ( late at night) than others. Sometimes you can’t imagine the sound could be much better; at other times, you turn it off after five minutes.
I’ve heard multiple explanations for this including dirty power (less people using appliances), the weather, feeling more relaxed in the late evening with the lights low, and lastly what seems most compelling, the differences in our hearing at different times of the day. Even my piano sounds better to me at certain times and obviously that has nothing to do with power.