I've had my 225i's now for a couple of weeks and I'm waiting on my first amp which is on back order-the Schiit Asgard 2. So, I haven't heard them amped, except when auditioning in a store. I'd be curious on thoughts re: amps. Please feel free to give me your opinions.
From what I've read, they don't really need an amp, but may sound a little better with one.
I listen to a lot of metal and rock. But, as an aging metalhead, I also listen to softer background music; indie singer songwriters, folk, jazz, some classical, soundtracks, new age.....
I'm playing around w/ different recordings determining what sounds best with these cans and what I might want at a later date. I like throwing a well recorded CD into a player, enjoy sitting with my stereo with my HP's and going back and forth from my 225's to the speakers comparing the differences. Sometimes, it's fun to crank the speakers sans cans and then go back to the cans and hear all the little details.
I agree w/ the consensus that they sound great for mid-upper range. Among other things I listen to genres of music called doom/drone/sludge/stoner rock which tends to be very base heavy. Frequently played on downtuned guitars that are recorded through base amps that create a massive distorted base sound. If you know what early era Black Sabbath sounds like-think Sabbath or steroids. Here, I think I'd like a little more bass impact. Alternately, some more sound stage on bigger symphonic recordings.
That said, I still find classical enjoyable and......
I REALLY like the front and center aggressive quality w/ most of my heavy rock music. I would say with blues and guitar centric music, these guys are the bomb. And, anything with really heavy distorted guitar-big crunchy, raw metal, punk, noiserock, hardcore, etc. the 225 are really excellent.
I also enjoy prog. Right now, I'm listening to Porcupine Tree's "in Abstentia" and I think this is one of the best listens I've had-that said, this is a proggy album with a fair amount of distorted guitar-kind of perfect!