Four Way Portable (Sony ZX2, iPhone 6, AK100ii, Chord Mojo) Shootout w/ Andromeda IEM

So I'm late to the game, but I recently upgraded from AK Jr to ZX2 for my Andro. The AK Jr was a decent DAP for its price with an optimal output Z for the Andro, but I wanted to see what the fuss was about with the ZX2. I managed to snatch one in near mint condition for less than $500, the price seems to have dropped significantly due to it being discontinued and replaced with WM1A/Z.

Correct me if I'm wrong, but the ZX2 has a slightly lower output impedance than the AK Jr, but it nevertheless lies within the sweet spot (1-2 ohms) of the Andro that makes it sound neither too lean nor loose. Here's a quick comparison.

AK Jr: smoother treble, more laid back
ZX2: slightly larger soundstage, less veiled

However, in the stock configuration (with every DSP turned off), I found the ZX2 to become a bit more fatiguing over an extended period of listening. I tried experimenting with several DSP that ZX2 offered, starting with ClearAudio+. The ClearAudio+ was utterly crap, with an inexcusable amount of treble fuckery, bloated bass, digital glare, it was almost Sabre-like. The very antithesis of a well-implemented NOS R2R sound.

Next I tried EQ'ing. However, I think Andromeda is one of the very few transducers that have an almost perfect tonal balance (along with Code-X and modded HD650) that doens't need EQ'ing to "fix" it. As I expected, screwing with its frequency response did more harm than good.

As for the surround sound, I know I'm sort of a minority in this regard but it came off as a rather pleasant surprise for me. Most DSP's I've encountered that claim to emulate surround sound failed drastically in one way or another, usually with a huge tradeoff in SQ. The only ones that I felt acceptable were Smyth Realiser and OOYH. While the Realiser and OOYH does sacrifice a bit of detail, their surround sound is well implemented and convincing enough that I would rather use them than not. It also makes the sound less fatiguing, since the music is not trapped inside the head between the ears. The ZX2's surround sound, the Studio setting in particular (the rest sounds unrealistic and crappy), seems to takes advantage of the Andro's B&K curve and throw a more spacious soundstage that I could happily live with. While the tonal balance doesn't necessary tilt toward the warmer side with the surround sound on, it does make listening a bit less fatiguing by making the mids less aggressive and forward. Alas, while the improvement in soundstage width was satisfactory, the soundstage depth left something to be desired compared to OOYH. I do remember Darin saying he may work on an OOYH version for Android devices, but as of now there's no telling.

And speaking of an Android device, I love how I could watch music videos on YouTube with this thing. Previously I had to watch it on my iPhone 6S which wasn't that bad for the Andro, but it still noticeably falls behind AK Jr and not to mention ZX2 in terms of sheer SQ. Now I use the iPhone only as a tethering hotspot to feed Wi-Fi into ZX2, and it works like a charm.