OK so I couldn't wait
Did some A-B testing on HDTracks headphone test disc flac files with KZ ZS5 vs ZST vs UE Triplefi10s shootout (my currently available IEMs) and here are my thoughts:
Sensitivity. TF10s is most sensitive and by a fair margin, while the ZST is slightly more sensitive then ZS5. I guess more DDs take more power to drive. This might also mean potentially more scalability with amping for the ZS5?
Soundstage and resolution. Listened to some jazz and the immediate difference is that with the ZS5 I feel like I'm sitting in a bigger room than the ZST. The TF10s meanwhile are very intimate, but provides more clarity and separation between instruments. There's almost an airy feel to the ZS5 vs TF10s that is similar to going from closed vs open back headphones. ZS5 has better resolution and much better separation than the ZST as mentioned in my previous post. The additional DD and BA indeed are doing their job.
Bass wise, TF10s is powerful and tight (well known). ZST and ZS5 are actually not that far apart (this may change with burn in, as my ZST is well used). ZST can rumble, but ZS5 rumbles with more separation, so the ZST bass is almost a little muddy in comparison. Neither are basshead level, but I do like the slightly stronger and more musical bass on the ZS5. I'm hoping more burn-in will loosen it up further, as the bass can sometimes sound a little tight on the ZS5 right now.
Mids the ZST and ZS5 are somewhat similar, very natural sounding for both male and female vocals. Not sure if the freq curve is biasing me, but I do get a feel there's less of a peak in mids for ZS5, more neutral sounding.
Meanwhile I've always felt TF10s were a bit too warm for female vocal dominant tracks, and this bears out here.
Treble the ZST and ZS5 are again similar, although the ZS5 does provides more detail than the ZST in the highs. High cymbals sound clearer on the ZS5 than ZST. But the main thing is that there's a track with female vocals S sounds that I can always hear some sibilance on the ZST, but this is GONE on the ZS5! For those who feel ZST was too bright/sibilant I think the ZS5 may be the ticket for you.
Overall the TF10s is quite a different animal altogether so I won't go into too much further detail. Between the ZST and ZS5, personally I feel the ZS5 improves alot on the ZST by getting rid of the sibilance, strengthening the bass and with more drivers we get better resolution and separation. Adding a wider airy soundstage with better spatial separation is just more icing on the cake.
I don't have my ZS3 anymore, but from memory the ZS5 should be closer to the ZST than the ZS3, which makes sense from a hardware perspective as well.
I tried the gold cable as well, really can't hear much of a difference (same experience with my ZST and ZS3 with the stock vs silver cable). It feels nicer than the stock, just like the silver one, but I need my mic and volume controls for daily commuting use.
Things I don't like about ZS5
- Hard angular edge design of the earbud makes it less comfy even during in my short hearing session. This does not bode well for longer listening (will try on my commute tomorrow)
- The nozzle on the ZS5 is a straight tube, while ZST has a notch. This means the tips fall off slightly more easily on the ZS5 vs ZST. With my A-B testing, there was indeed 1 time that the eartip was left in my ear when I pulled the ZS5 out
- Memory wire on both the stock and gold cables, although this is easily modded by cutting the wire out
Anyway all in all I like the ZS5 quite alot! I didn't think it was possible at this price point but the ZS5 indeed can give a performance at like 90% of TF10s level of IEMs. Add in the inline mic with volume buttons that work with ios and android and I am now one happy head-fier