I promised more updates on the Clear some time ago. It's time to revisit it, considering that I've had these headphones for a while now.
Out of the box, they perform well, but not $1500 well. I think the bass is excellent, probably the best I've heard out of an open, dynamic driver headphone. The mids are solid, good tone and resolution all around but I've heard better, mainly out of electrostatics. The highs, however, are a bit of a let-down, as they're overly sharp, slightly artificial, and lack resolve compared to high-end electrostatics. The soundstage isn't the biggest and imaging is a bit confused, though the dynamics and tactile punch are all excellent, as has been said.
So, not content with the level of performance I was getting, I busted out the diagnostic tools, mainly a test tone generator with a frequency slider. This way I can listen to the frequency response directly, without having to rely on measurements and trying to work out a compensation curve that compares what the mic's hearing to what my ears hear. And what I heard was pretty telling.
The highs have a series of closely spaced peaks - roughly at 6, 7.5, 8.5, and 11khz, respectively. The 7.5khz peak is universal to full-size headphones for me and doesn't show up in most measurements. The other 3 do show up in some of the measurements posted on a certain not so friendly site, and those measurements are pretty spot on with what I hear.
Whenever you have closely spaced peaks like this, you tend to lose detail in whatever frequency range they reside in. This is due to a phenomenon called masking frequencies. In essence, the brain has a tendency to fixate on whatever sound is loudest, and ignore sounds that are quiet, especially when those sounds are in a frequency range right next to the frequency response peak. So if you have a peak at 6khz and another at 7, you're gonna lose some detail at 6.5khz since the brain will gloss over those sounds in favor of the louder peaks. I think this is why the highs seem artificial and not very resolved on the Clear, at least compared to electrostatic headphones.
Fortunately, the gods invented equalizers so we can fix some of this. Using a decent EQ plugin I created a profile that smooths out the highs. It's a big jagged, and I'm still working on it, but listening to a sine sweep with the EQ on, the highs are now smooth.
Once I got the highs to behave, the Clear pretty much transformed. Gone is the sharp, artificial sound, and in its place is remarkable smoothness and resolve. The imaging also improved, since depth cues are now being represented correctly, and the overall sound is open, airy, and clear. Comparing the Clear to the Stax L700, the Clear actually outresolves the L700 a bit in the highs, and certainly in the bass. I think the L700 has a more natural midrange and its soundstage is wider, and its imaging is better, but the two are neck and neck now, and they weren't before. Granted, I'm also EQing the L700, which is less neutral than the Clear overall, though with a notably smoother response.
I really like the Clear now. One of my favorite qualities in a headphone is the combination of liquid smoothness and resolve. The truly great headphones do this, and up until now, electrostatics did it better than anything else. But here's a dynamic, and I'll be damned if it isn't doing the same thing, and even better than some of the 'stats I have.
Are there still problems? Sure. There's an audible resonance somewhere around 3-3.5khz, or maybe around 4. Listening to a tone somewhere in that frequency range, I can hear some ringing. In most other spots it's a pure tone, but in that range there's something going on. I can't fix it with EQ so I'm not gonna worry about it, but it does affect the sound a bit, and some of the higher-pitched vowels in vocals have a slightly unnatural character to them. The highs are also a bit metallic sounding. I've read that resonances just beyond the audible range can cause this, and sure enough, the Clear has a measurable resonance somewhere around 22-24khz.
So nothing is perfect. But I think I'm keeping this one. At least until something better comes along.
P.S. I'm not gonna post the EQ settings cause I'm still working on them, but come up with your own. My ears aren't that great anyway. Yes, you lose some detail and dynamics with EQ, but if you use it correctly you gain more detail and accuracy than you lose. I'm kicking myself now for the years and thousands wasted looking for the perfect headphones, when you can simply take good headphones and make them better with a little bit of effort. Though you do need to start with something that's reasonably close to neutral and something that performs well, cause if you have a dog, no amount of EQing will fix it.
... damned Focal.
