1) The headband can twist out of straight-line, minor design flaw.
2) The CRBN has a serious "e-fart" issue. I first tried listening to them right when they arrived, and the temp/humidity of my room must have been too hot because just having the two pads lightly touch each other created serious distortion noises. On-head, even a minor touching shift caused a thunderous cracking noise. I'm giving them another go now since the temperature dropped ten degrees, and the effect is minimized but still apparent. You need to put these on or off your head very carefully - the sound it creates is 85+DB right next to your ears. Other people who were asking about this: this is not normal for any of the Stax models (6?) I've owned. I contacted Audeze to make sure this isn't a defective unit because it seems insane to think they thought this was acceptable for a commercial product.
First impressions sonically:
The CRBN is sonically a step down in terms of clarity/soundstage and an even more significant step down in detail/separation from the Stax 009S. The CRBN has less bass than I expected too; the Sr009S is not that far off when I use the Carbon amp.
However, that's the "on paper" look at things. CRBN has a totally different game they're playing. The presentation is so diffused compared to 009 that it has an extraordinary "filled-in" effect. As mentioned before, the bubble of the soundstage is perhaps half(?) the size of the Sr009s, but it has the illusion of seeming like it can create sound in all directions within it (up/down, diagonal), where the Stax sr-009s is more like a straight string from ear-to-ear, and images appear highly separate on that string. I heard a song on the CRBN where an instrument moved from the back of my head to the front ... don't think I've ever listened to any headphone capable of such an effect. Instruments blend together, but in a musical way that enhances the harmony. Voices, for whatever reason, cut through the separation better and sound tonally correct. I find myself less fatigued, tapping my foot more, enjoying music. This headphone has a lot of soul.