I'm on the Australian listening tour for the 1Plus2 with and it just landed in my lap today!
I've been listening casually for a few hours on my ODAC / Objective 2 using green Sony foam hybrid tips. Apart from my beloved Sony MDR-EX1000 and now a Audio Technica ATH-CKM1000 I do not own any other IEMs that approach the price of this unit. Here are my first impressions.
The build quality of this IEM does not correspond with the price tag. There are plastic joining seams on the cable connectors that I would not expect to see on a $1K+ product. The cable is not very supple, though it seems durable. The 3.5mm jack looks literally as if someone has attached a banana plug speaker terminal to the wire. The build seems very boutique-fi.
I currently also have a demo unit of a Null Audio Rooth Elpis in my possession which is a 3D printed universal hybrid 'custom' IEM that offers basically the same build quality for about $250. I imagine complexity of engineering must be similar between the two (though the Elpis I have is a version prior to a recent revision) so at least in terms of build the 1Plus2 is disappointing.
In terms of sound the 1Plus2 is technically very impressive. In terms of signature they actually remind me of my Sony MDR-7550 except that bass extension and emphasis is more visceral and extended. Everything sounds very clean and definition within the soundstage is startling. The bass also lends everything a sense of scale and probably stands out to me as the best feature of the sound.
I understand that out of head soundstaging is meant to be a strong point of the 1Plus2, but to my ears it sounds a bit more intimate in width and spaciousness compared to the EX1000 and 7550. This is to be expected since the EX1000 and 7550 are partly earspeaker designs.
Definition and clarity within the soundstage seems a bit better on the 1Plus2 because the TWFK drivers do not have a lot of decay. By the same token (and I generally always feel this way about TWFK's and BA's in general) the timbre is a bit off and feels just a little tacky at times to me in the highs.
There is some forwardness to the upper vocals or the lower treble that pops up in a few tracks (particularly more recent studio recordings) that gets a bit grating for me. Generally though on most tracks vocals are smooth and have a delicate detail to them that I quite like.
Sometimes I get the impression that the sub-bass sounds a little 'blunted' or 'ragged', but I'm still trying to work out if this is just because sub-bass extension is so low. (Will do some more comparison with the XBA-40 to check later).
All in all my first impressions are very positive - I think these sound fantastic. However I do not think the sound is as transcendental as the price tag would suggest. Diminishing returns, putting a price tag on a subjective experience, yadda yadda.