These are for my open heaphones:
AKG Q701 -
One headphone that gets nearly everything right for me. It's not forgiving at all though and bad/harsh tracks can be a little annoying. Mine is quite warm and full sounding. No goofy sounstage and those lean mids of the K702. I'm using a DIY Canare cable with it now and it now sounds closer to the HD-598, but with more treble and a clearer sound. IMO with the Canare this headphone would be ruined if it had any more bass or was even warmer. I don't really love it's angled pads though. The bumps don't bother me. Sorry, but this headphone is worth investing in a nice dac/amp for. I bought my Headroom Micro Amp just for this and the HD-650. Totally worth it My ODAC made this even better and even more balanced sounding. No kidding..
AKG K601 (tied with HD-580)
This is one headphone i'll keep forever. Sounds like it has fuller mids than the Q701 at times, yet it seems to have less bass. Sometimes I can't figure out this headphone. It's mids often seem less forward than that of the Q701. I would say this sounds slightly more balanced than the Q701 (at times). It's treble is a bit smoother. The negative of this headphone is that it's worse than my Q701 on harsh/fatiguing tracks. Not sure why. Not as clear or detailed as the Q701. Comparing this to the Q701 is just so annoying. BTW it does have better imaging than the Q701. I think it's due to the pads. This has not been used much since getting the Q701.
Sennheiser HD-580 (tie)
I got this for $150 and thought it'd sound the same as the HD-600. Wrong! I find it sounds like a slightly more fun version of the HD-600. Perhaps less bass, a clearer sound and more forward upper mids. Not huge differences, but very slight. The soundstage is rather small for an open headphone. This seems to have more treble than my HD-598 somehow! I tried my HD-600 grills on this and it turns it into a snore fest. I prefer this with stock cable. Looks like I'm not the only one out there who thinks this sounds better than the HD-600!
This is one smooth sounding headphone. For me it's very musical and perfect for asian pop. Especially the type with female vocals. This is what I'd suggest for those with budget amps under $100 and want a good all rounder. It won't please bassheads though. With the MAP pricing, it's hard to suggest this over the Q701. I don't think it's worth $250. This even manages to sound straight out of my Clip+! With my setup right now my HD-598 actually sounds like it has less treble than my HD-580. Strange.
AKG K240 Studio
One of the best budget headphones there is. Mine seemed a lot bassier out of the box, but this went away somehow. Despit being being 55 ohm, it needs an amp.
Puts me to sleep and no I don't find it neutral, but close. That wasn't why. I can only like this with mods. Something weird about it's bass. I think the upper/mid bass causes some sort of fog over the entire signature. Modding it fixes this and really clears up the sound. My HD-580 doesn't have this issue. Despite being called "fun", I think the HD-580 sounds more balanced.
Audio Technica ATH-AD300
Slightly better than the AD700. Fuller mids, more bass and way less treble. Discontinued. I got it at Wal-mart for $35!!
There's something special here, but too bad it's kind of thin and has too much treble. I think a tube amp might be the only way for me to stand it's sound. I'm a semi treble head too.
not enough bass, thin, too much treble. Sounds weird. Sounds clear and is detailed (don't say it).
Terrible fit if you have a small head. Yes, I'd buy a headphone (such as this) just for gaming.
What else has the soundstage, detail and clear sound of the Ad700 for under $100? Nothing!!
The HD-668B comes close in several areas, but that is more V-shaped in signature.
AKG K240 Sextett LP
Probably the worst headphone I have right now. Very muffled sounding with a severe lack of treble. The treble only comes back if I remove the inner foam. Then it's too thin! Maybe mine is a lemon.
Yuck! Don't know what's wrong here, but actually this is nearly as bad as my Sextett LP. Maybe both are lemons. Maybe this needs 200000 hours of burn-in. Sounds very, very dark without much treble. Very muffled.