Sold my SRH1540 last week, it just wasn't for me.
I've come to the conclusion that closed headphones just don't work for me in general for any kind of music listening. Though I do own the Audio-Technica ES7, I don't use it for music listening at all, it's solely a "computer" headphone for me (DVD & streaming movies, gaming, etc). Plus it's cheap so I don't expect it to sound "great".
I sold the SRH1540 for a reason similar to why I also sold the Fostex TH900 previously—neither was sufficiently "open"-sounding enough and the cut-off decays in especially ambient electronica were extremely annoying to me. The TH900 aggravated me because of that, and of course the closed SRH1540 did the same for me. I think if I ever get another closed headphone it's going to be a <$300 model to replace the ES7 as a computer headphone. Just couldn't tolerate the SRH1540's lack of properly-full decays, or the TH900 for that matter for the same reason.
Other reasons I couldn't get into the SRH1540 included its lack of clarity, lack of treble quantity & extension, and a bass response that just sounded too intrusive. It's not the bass
quantity that bothered me per se, moreso its quality. I thought it just intruded too much into the mid-bass/lower mids and made too many genres of music sound too indistinct. And I thought I'd like its bass for electronica (specifically The Crystal Method, The Prodigy, & Infected Mushroom), but it didn't do anything for me for those artists in terms of bass. I can't describe why exactly, but its bass was just boring and reminded me of the HE-400's indistinct ploppy mess. I vastly preferred the KEF M500 back when I owned those headphones, which had just the kind of bass that I like for electronica and had really good quantity & quality.
I just never enjoyed any type of music on the SRH1540 and I did throw every major genre that I listen to at it—classical, bluegrass/folk, electronica/trip-hop, & metal. Not that I'd call it "bad" though, I'm sure it'd be fine for other people, but I just couldn't put up with it personally.
Easily my biggest headphone disappointment in a long time.
I'd been hoping for something more similar to the open SRH1840.
I was able to try the headphones on two amps btw, the HeadAmp Gilmore Lite and Garage1217 Project Ember, neither of which helped me to like the headphones. If anything I was expecting the Gilmore Lite to help fix its bass overbalance and bring out the treble, but that didn't happen.