Power conditioner question

Most everyone has tried this. That's what power conditioners do. I have a dedicated outlet and two conditioners. Sounds the same anytime of day or night.

Music sounds better at night because there are fewer demands on the AC so your AC is cleaner, though it seems as quiet in the afternoon, there has to be less white noise at night, and because
at a certain point in the evening, you become more relaxed. If you
dim or turn the lights off, your hearing will also become more acute. Dedicated circuits and an AC conditioner will help you get
that "late at night" sound -- BUT -- it will also improve your late at
night sound, so your standard will rise and your music is still likely
to sound *best* at night. But, it is a nice probem to have. Start
with properly grounded dedicated 20 AMP circuits with Hospital
Grade outlets.

A large part of it, perhaps most of it, is in the mind, but it is real, not psychological. The visual cortex is extremely "power hungry", as it were, and so any extraneous visual activity will reduce the apparent acuity of the auditory system. That is why closing your eyes or listening in a pitch-black room results in such a dramatic improvement in apparent sound quality. I am not making this up; it is one of the most underappreciated aspects of psychoacoustics and has profound implications in all kinds of ways, most of which are beyond the scope of this thread. Suffice to say that for maximum enjoyment, you need to reduce all extraneous neural activity as much as possible. Often the best time for that is late at night.

While I fully believe in the benefits of power conditioning, I don't necessarily ascribe the difference in performance late at night to just power quality. There are other factors that can have a much greater impact. Rsbeck mentioned the psychological impact at night, and I think there is one even greater - reduced noise floor.

Almost everyone knows that a house is more quiet at night. The air conditioner runs less, TVs aren't on, water isn't running through pipes, less cars may be passing in front of the house, other people in the house are likely talking less, etc. If the noise floor in your house is lower late at night, then you absolutely SHOULD hear a difference in your system unless you listen in a sound-proof room. Use an SPL meter and take a reading in your room without your system playing both during the day and at night. If you find a difference, then it undoubtedly is one of the factors contributing to the perceived difference in performance.

It would be interesting if any electro-freaks here would check their voltage with an oscilloscope or spectrum analyzer at various times of day/night. I believe that you will notice that the power is definitely cleaner in the "wee hours". The psychological explanation also causes a "better sound at night". I also have noticed that my hearing tends to be more sensitive to volume in the morning, shortly after waking. My car stereo's volume was always set lower driving to work, and MUCH louder in the afternoon. I also believe (no proof; just speculation) that the Fletcher-Munson curve (your hearing's sensitivity to various frequencies) will change from morning to night.