After spending over 100 hours with the He1000se, I've concluded that SE stands for Soundstage Edition.
The standout feature, and what truly wows, is the soundstage. It's noticeably more precise than the He1000v2. Background instruments are completely separated, giving the sensation of listening to individual tracks of sounds. However, on poorly recorded tracks, this precision can highlight clips, distortions, and recording errors.
With high-quality sources like Amazon Ultra HD or FLAC, the He1000se shines, offering a 3D-like soundstage. It's akin to watching a movie on a 4k 120hz TV when the film is recorded at 24fps. In comparison, the He1000v2 feels more like a 1440p Ultrawide at 60hz.
The He1000se is remarkably revealing, almost as if you could master music as you would with a very high-end studio monitor.
The midrange vocals can be quite impressive and comparable to the He1000v2, especially when upsampled to DSD 256 or higher with HQ Player using Poly Sinc Gauss Hire LP + ASDM7EC Super 512 fs."
Although the power requirement is significantly less than the He1000v2, the He1000se is still source-dependent. The super transparent nature of the He1000se means I can easily tell the sound difference between a USB cable (Supra vs Oyaide) or if there is a Linear Power Supply (LPS) vs wall wart.
The source chain used is:
Netgear GS108 w LPS - IFI Stream w LPS - U18 DDC - X26pro - OCK2 - Soloist 3x - He1000se - Hq Player