Welp, I am once again an M1570-Open owner.
First time I owned it, I was underwhelmed, finding it too mellow for what I wanted from a planar. Meanwhile all the talk about how exciting and engaging the Hifiman HE6se v2 is, I sold my first M1570-Open and got the Hifiman to replace it. And the HE6 is definitely super-detailed and super-engaging (given adequate power), but it's just too bass-light for me, no matter how big a bass shelf I slap onto it in EQ.
I've also come around to the idea that maybe the reason I found the M1570 too mellow the first time was more to do with my amps than the headphone itself. Back then, I had (and still have) a Liquid Platinum, which a lot of people like to pair with this headphone, and is indeed my favorite amp to pair with my favorite headphone, the E-Mu Teak. But I think it turns out I just don't like the planar-on-tubes sound, plus the particular tubes I have fitted probably contribute quite a bit to the perceived mellowness. The other amp I tried it on was the Singxer SA-1, which is very warm and musical and a great complement to a good few headphones in my collection, but... not this one.
This time around, I have a Schiit Jotunheim, a RebelAmp, and a Liquid Gold to pair with this headphone. If one of these amps doesn't do it for me, nothing will, lol
Between the HE6 being imperfect and inconvenient for me, a sense that this headphone might be discontinued soon, the recent killer sale price, and my expanded amp selection, okay fine, I'll give it a second shot. It'll be especially interesting to compare it directly to the HE6, as an owner of both simultaneously.
I also technically own the M1570-Closed, because that, too, recently had a killer discount. However, my M1570C is currently in Oratory's lab, because his EQ is extremely transformative for the Open, and the Closed could benefit from similar transformation if possible, and I was the first Closed owner to reach out to him to volunteer his unit for measurement. I'll eventually have the M1570C back, and then it'll be especially interesting to compare the HE6, the M1570-Open, and M1570-Closed.
We'll see what shakes!