Listening after your entire system was powered off cold for a week+

I do notice better sound when system is on as well as when it’s ‘up to temperature’. Though it could also be I warm up into listening too!

My setup is rarely powered off for more than a few days. That is, the DAC/preamp and digital XO is running 24/7, and so normally the sound has that sense of presence and fullness immediately after powering up the amps (3 of them; one class A and two class D-based) and music server, but after an hour so playing music/movies everything coheres and falls into place a bit better.

8-12 hours after being all-powered up (only on certain weekends, and not with the kWh price of electricity these days) a more pronounced sense of liquidity enters the stage, which must due to the class A amp "settling" more effectively, or so I gather. While a lovely extra addition to the sound this a wee bit more free-flowing sensation is not a "must have" for me to truly enjoy the presentation.

Having had the amps and music server turned off for more than a few days - like a week or two - can lend a stiffness, grayness and slight distance to the sound right after power up, and so the warm up change appears more radical and also takes a little longer. A couple of hours usually suffice here.

Interestingly the most radical boon during warm-up comes from playing my setup relatively loud (i.e.: 85-90dB range, slightly more in peaks) for an hour or so. This is most likely to occur during a listening session with one of my fellow audio compadres or watching a movie at ref. volume, and the effect is quite noticeable. When on my own I sometimes leave the listening room for 15-30 minutes and the music playing in mentioned dB-range, and it has close to the same effect. The sound just "pops" more freely and fuller after such a workout (that is, to my speaker setup it's hardly a "workout," but more like a light evening stroll), and so this is something I desire when listening more attentively. I’m guessing the speakers are to "blame" for this positive effect.

@phusis "Having had the amps and music server turned off for more than a few days - like a week or two - can lend a stiffness, grayness and slight distance to the sound right after power up..." 

Thanks for sharing the background and the details below it about how it sounds when you’ve had it playing more aggressively. I’ve noticed something very similar over the years yet failed to mention this in the OP. Interesting in any case, 👍

Never.

Most of what I notice is slowness getting Ethernet connected again with the network sreamer and innuos needing an IP refresh.  As far as sound, once everything is updated sound has been the same for me. I'm on comast if that matters.