Imo looking for bass-light, mid/trebble emphases, and open can. I have a neutral iem in the sm es18. I'm looking specifically ff something with better instrument separation, and headphones that emphasize string instruments.
Sent from my LG-VM670 using Tapatalk 2
Sony MDR-F1 perhaps, if you can find one. They're sort of mid/lower-treble emphasized, one of the thinnest (but best extended) headphones I've heard/had, and they don't burn your eyes out from the back with resonance. They're very listenable "happy" headphones. Again, if you can find one (that's the problem - if you find prices in that $400 range that I've heard about recently; walk away - original SRP was supposed to be like $200). Double for the MDR-SA5000 (brighter, less extension, faster/more "analytical").
Beyer T70 (I know we're *way* over budget now) would probably get you what you want in spades (and it WILL burn your eyes out from the back). Just something to keep in mind down the road is really the only reason I mention them.
Other considerations in the "cheap" category might include the Pro4AA (I have not tried them, but they are consistently reviewed as very top-heavy or n-shaped in their response, and they measure that way as well: http://www.geocities.jp/ryumatsuba/pro4aa.html - they also weigh like 600g so I've stayed away). Good availability and warranty on these. CSD doesn't show tons of ridges up high, so they probably won't burn you to death. $99.99 from Koss direct or Amazon - should be FS on both in the USA (these get hilariously expensive outside of the US; I've been told by some Okinawan friends that these run the equivalent of like $250 US in Japan).
Grado is the other manufacturer I'll suggest - and while they aren't circumaural/around-ear, the comfies that come on the SR-60 will not be bothersome for long-term usage imho (they're better than the bowls or the lambskin pads on the ESW9 (I would not suggest the ESW9 even be thought about btw; they're bass HEAVY)). They'll hit up high quite readily, and are relatively "airy" (but it's not the same as the ethereal presentation of the F1).
Finally, and this will take some looking on your part (and probably a lot of patience) - track down a used electrostatic set. TMK the only "dark" 'stats are the older Koss ESP models (ESP/10 for example), most of the rest of them (including the new Koss models, which go out of your budget) are fairly mid/treble driven with "thin" and "airy" bass and excellent separation/tonality. They also don't burn your eyes out. You'll probably end up with a transformer box and headphones, and need an outboard power amplifier, but I'm guessing you (like many people) either have one, or have access to a thrift shop and can pick up a used stereo receiver for $10-ish dollars.
Based on all of the above, taking your personal preferences and biases into account, the Pro4AA is probably where I would start; Amazon has a 30-day return policy, so it's more or less "risk free" if you're unhappy with them for whatever reason (fit, sound, etc). Otherwise I'd save pennies or scrounge up an old ESP.