Great thread. My M3s arrived on Tuesday - I'm a newbie and the speakers I had are 30 years old (but sound very good) but I don't have the ear or the experience (incl comparing against other speakers) most of you do. That said, to me they sound amazing out of the box (speaking of boxes I need to figure out where I'm going to store the Hobbit caskets

as I don't have much storage space left) on my "clean" recordings that don't have heavy electric guitar. My older speakers had the same issue where the high mids and treble collide and distorts even at 80 db (meaning not crazy loud) levels. Because my old speakers did this, although they are much, much smaller, I wonder if any of it is in my system but will stay patient.
For example, Voodoo from Godsmack is a fairly "clean" song but Whatever on the same album is not - meaning heavy electric guitar and generally a "noisier" song, but one which I really like and have the guitar and symbols "crashing" together.
Take 5 sounds amazing as does Tosca , Suzuki, Fleetwood Mac, Rumours and about a dozen others but - and this may be the recording, Rush Moving Pictures, 180g sounds (relatively) awful.
Because I had this issue w/ my other speakers I keep wondering if it is my system but will continue to be patient as they have a whopping 3-4 hours on them.
Also, the rest of my system is only a month old so the amp/tubes, TT, cart and phonostage (with tubes), cables and speaker wire are all breaking in. So.... I will continue to be patient as I REALLY ENJOY

my speakers on the recordings it likes right now Will then reassess. I literally have permagrin the whole time I'm sitting in my listening chair listening to my new system.

Question: How loud does the music have to be to be considered counting towards break in? Meaning is 60 db enough or does it have to be 70 or 80?