@b_limo --
Same-ish thing happened to me when I picked up my horn speakers in Brighton, UK back in 2015, and drove them all the way to Denmark in a van - in December (in Northern Europe, where it gets cold in the winter time). Arriving early on the day some hours went by assembling horn sections and cross-overs, and finally by the end of the day when I hooked them up (they'd been broken-in some 2 weeks by their maker after being build), having now gone through some period of acclimatization, they sounded anything but broken-in, but rather thin, "high-strung" and outright dull. I then let some music play through them at a bit more than moderate levels for a couple of hours, and when I came back it was night and day; now they sounded fully relaxed, open and naturally warm. What accounted for this radical change in sonic presentation, I can't say, but several factors might have been involved - the most important of which could've been the whole temperature shift and for all parts, including the horns and overall enclosure, to settle in.
Interestingly, I also find speakers to usually sound better when they've been given a good workout for a period of time, and I mean speakers that have sat in your system for years even and are fully broken-in. I assume it's not the electronics - although there are gains to be had here as well when they've been turned on for hours, or days - because the presentation doesn't apply to this phenomena with only moderate to low SPL's. If we assume speakers generally respond positively to being played at elevated levels for some time (not to the point of excessively heating up the voice coils and x-over part where heat becomes a negative factor), then what's to account for this change? I don't know. Something tells me it's the drive units and not the passive cross-over parts, but I've very recently acquired new (used) cinema speakers that are fully actively driven, and if they respond the same way (haven't found out yet) I take it that rules out the XO.
