I auditioned the entire A series and Z series in our local sony store the other day. Brief impressions -
A1 - Sounds really good for the price, and not all that far away from the bigger brothers. It is a massive improvement over the H1 with a more balanced sound with an overall performance that is close to my GR07. Sound signature is V shaped and sounds quite clear. High frequency extension is a bit lacking but it is really smooth with no sibilance. Bass is strong with decent extension but it rumbles a bit less than the GR07. Compared to the GR07 it offers slighly better clarity and smoothness at the expense of a more colored sound, but performance is on a similar level. Arguably this is one of the better values out of the entire series.
A2 - A big improvement over the H2, which it should be considering the H2 was dual driver while A2 is 3. I would say its on per with the H3 with a similar sound signature as well. Very strong bass, borderline bass heavy in fact, but the mids and highs are not really overshadowed. Separation is excellent and the overall balance is pretty natural and enjoyable. This reminded me a lot about my (now gone) H3. I like it more than my GR07.
A3 - I would take this over their previous flagship, the H3, any day. The overall balance is superb with the bass, the mids and the highs all presented equally. The upper mids sounds a lot more prominent compared to the H3 and more in line with the rest of the spectrum. The mid bass is also scaled back, allowing the mids to breath. Overall, it sounds a lot more natural and livelier compared to the H3, and sounds like whatever flaws they had with their previous flagship have been addressed here. Overall a solid earphone a good step up from something like a GR07.
Z5 - The new flagship. Compared to the A3, the Z5 sounds more fleshed out and there seems to be better separation between the lows, mids and the highs. It also sounds more open and a bit more refined. Instrument separation is really impressive, never sounding congested. Despite the strong bass, the mids are not recessed at all and has great clarity. It is a solid improvement over the H3, However, while the A3 is almost half the price, I would say the Z5 offers roughly about 15 ~ 20 % improvement.
Impressions were done using a Fiio X1 in a busy environment so please, take my impressions with a grain of salt.
like SSOGE), due to wider and deeper sound stage, better clarity and separation, especially from balanced output – so genres like funeral doom, death/doom, sympho/atmospheric black (Carach Angren are just perfect on them) sound the most interesting here. With the Z5 you don't want to move but sit and listen.