I finally got a chance to get the Borealis in. Big thanks to JP for making that happen. Here are my initial measurements on the GRAS 43AG:
Borealis vs Harman Hybrid (Harman 2018 mids and treble but 2013 bass)
Borealis vs Focal Clear
Borealis vs Focal Utopia
I’ll add more measurements here as I switch pads. But some general thoughts:
My initial take is that the Borealis is an excellent sounding headphone! It’s surprising how close to the Utopia the Borealis is for frequency response - at least for the upper mids and treble. There are two notable areas to look at, namely the slight midrange emphasis around 1.2khz and the 5.5khz peak. I find that both of these areas are audible, but it’s not a big deal. Keep in mind that the dips you see around 9khz are the result of concha interaction (meaning they should be there, and this is not something to EQ).
For technical aspects, it has excellent punch and slam and really good instrument separation. I’ve been comparing it back and forth with the Focal Clear, and I find that the Clear is just a bit more detailed sounding, with slightly better dynamics. But the Borealis has a kind of tightness to it that’s really enjoyable and engaging as well so it’s no slouch. The soundstage is still something I’m figuring out, as it does sound like it has good lateral definition and distance, but the center image doesn’t have all that much depth to it. And so while it’s wider than the Clear, I find I prefer the Clear’s imaging at the moment. But more testing is needed.