I'm currently in search of the best headphones around $300-$500, maybe higher if it's really good. I tried several of the recommended ones, and found problems with them, so I was wondering if anyone had any suggestions. I currently have the DT990s. The only thing I don't like is their sibilance.
Here's what I tried and what I thought of them:
AKG K702:
+Good detail
+Good sound balance
-Lacking slightly in bass impact and extension
-Unnaturally wide soundstage made music sound too broken up
-Very uncomfortable headband
Stax SR Lambda Pro (not mine and very expensive):
+Excellent detail and sound quality
+Excellent soundstage
+Excellent bass extension
-Lacking in bass impact
Beyerdynamic DT990 600 ohm:
+Good soundstage
+Excellent bass
-Lacking slightly in bass extension
-Annoying sibilance due to peak in response around 8-10kHz
Bose Triport:
+Good sensitivity
+Excellent bass extension
-Small soundstage
-Poor tracking
If I had to rate these not taking into account cost, I'd rate them:
SR Lambda Pro: 9.0/10
DT990: 8.0/10
K702: 7.5/10
Triport: 5.0/10
Don't take this the wrong way but what kind of perfection are you expecting for $300 to $500? There's no such thing as a perfect headphone, but the top of the cans from practically every major manufacturer are at least double the price you want to pay. If you're finding fault with these, what makes you think you won't find fault with others in your desired price range?
The K701/K702 is a headphone with a lot of soundstage and nice detail, but it's always going to be limited on bass. Why? Look at its architecture. You have a minimally filtered driver with the barest essence of an air chamber. The result is not airy by accident, but you'll need the right amp to get good bass.
The HD650 is more laid back. For awhile, it was Sennheiser's flagship, stealing that spot from the HD600, but its place at the top was always controversial. If you look at the FR Graph on these two headphones, it's clear that the HD650 is darker than the HD600 for an obvious reason. Some thought the HD600 could use more bass, so Sennheiser tweaked it to get better bass extension. The result was the 650, which has more bass presence than the HD600 but less HF extension, an issue leading to the claim that the HD650 has a "veil." With the right amps and cables, Headfiers have found ways to make the 650 shine but the tonal shift is neither isolated nor accidental.
If the HD650 is too dark, look into the HD600. You'll get easier bass from the HD600 than from the K701/702. Sennheiser uses a lot of filtration to tame the highs and bring up the bass (It's really not much more complicated than that). Over at Team Grado, there's a restlessness with Sennheisers which, compared to the Grados, feel lifeless, but it's a difference in approach: one is laid back, the other on the edge. People who like Sennheisers tend to not like Grados and vice versa (Notice I said, "tend," as I have the PS1000 and the HD800 and am as happy as a clam).
If the DT990 is great but a little too sibilant, why stop looking at beyers? Beyerdynamic has the DT880 in various configurations, with impedences ranging from 32 ohms to 600 ohms. The DT990 gets some criticism over its sibilance (though there are ways to fix that - from changing amps to changing cables). The people criticizing it are much mike the people criticizing the HD650 as a replacement for the HD600 (though, over at Team Sennheiser, it's an issue of relative darkness, with the HD650 shifting balance for the sake of bass extension). The DT990 was meant to replace the DT880, which has such a loyal following that a number of beyer fans prefer their old 880s to the top-shelf T1. Again, however, you have to remember that the DT880 comes in different configurations, some of which are preferred over others.
To be sure, an FR chart can only tell you so much, but take a look at this one. The blue line represents the DT880/250. The orange line represents the DT880/600. The red line is the DT880/32 and the green line is the DT990. Lines aren't sound, but if we're just looking for some point of comparison regarding sibilance, this chart is as good as picking through anecdotes, especially if the replies are coming from people who don't have all four or who haven't heard all four.
If we're taking that spike around 8 kHz as our measurement of sibilance, the 880/32 and the 990 are the most sibilant in this group. The 250 and the 600 are 4-5 dB softer at that first spike. I doubt the second spike is an issue, since it's several dB below flat at 15 kHz. If the 990 has sibilance that would bother somebody, it would be at that first spike at 8 kHz. If you liked the DT990 but the sibilance bothered you, maybe you should scale back to the DT880, which some people still like better (beyerdynamic's version of the HD600/HD650, RS1/GS1000 feuds).
While the HD650 will give you more bass presence, the DT880 may be worth a second look. As you track that green line, you'll see it has less midbass but provides better low-bass extension up to 20 Hz and respectable low-bass extension up to the mid-bass hump. There's an 4 kHz spike but it's 3 dB below the 990 and 6 dB above the HD600/650's -2 dB spike before troughing again. Even so, the 600's drop to -6 dB before it spikes again to -2 dB is quite different from the 650's trough to -16 dB. Look at how these headphones end at 15 kHz. Would you rather be close to flat (DT880) or at -8 dB (HD650).
If I were a betting man, I'd bet you'd be better off with either the HD600 or the DT880. Between those two, I'd recommend the DT880.