I forgot to follow up on this. So I'm comparing between the HM-901/Balanced amp module (fw 1.085 April '14 version) & Calyx M (fw 0.96) :-
1) JHA Roxannes
- mids on the Calyx M seems fuller (which is closer to what I'd expect) compared to the HM-901. Stage width on the Calyx M is narrower than the HM-901. Still overall decent presentation by the Calyx M
2) FitEar TG!334
- same with Rox. The mids are more prominent on the Calyx M than the HM-901.
3) FitEar MH335DW-SR
- the same with the MH335DW-SR although with this, I kinda feel it's leaning a little towards the lower mids that's pushed forward.
4) Noble K10's
- the mids are again more prominent on the Calyx M but with this, the trebles seems a little more rolled off compared to the HM-901. I didn't notice this with the other BA's above. Combined with the commonality of soundstage width as with other BA's, the Calyx M feels somewhat more "compressed".
Comparing back 'n forth between the HM-901/balanced amp/v1.085 vs the Calyx M 0.96, ignoring the sound stage difference, the Calyx M feels somewhat more linear than the HM-901 which seems to give a little more of a U-shaped presentation across all 3 of these IEMs. What's funny is that I never considered the HM-901/balanced amp as "U-shaped" prior to this test.
That's all tests I've done so far. I don't have any DD IEMs aside from the loaner Ditas which I've already commented on. It's rather unusual on how (multi)BA differs from DDs on the Calyx M vs another player.
Let me know if there's anything you'd like me to test and share my thoughts.
Thanks for this. Your impression of the M's mids with BA IEMs seems to be more in line with mine now. I do think that the treble is a bit rolled off also which I personally like at least 90% of the time. I hate jangly treble. It, and the overall smooth musical sound signature of the M have some interesting results. The M + Heaven VI is making early Husker Du (Zen Arcade, New Day Rising) sound rather well produced. Actually the sound is quite compelling. These albums were post-punk rough production in the first place and then transferred terribly to CD. This discovery is very pleasing. At the opposite extreme, Jesse Cook's flamenco guitar seemed a little too smooth during my listening yesterday. I felt that the guitar strings needed a bit more twang in the plucking. Generally though, the M sound signature is perfect for me, especially with the aforementioned Heaven VI. It is my favorite portable setup yet. I can listen for hours immersed in the euphonic detailed splendor of it all with zero fatigue.
I wonder if adding 1.1 ohms of resistance (as certainly needed with low ohm dynamics like the Kaede) will also add a little treble and reduce the smoothness with BA IEMs. I really have no reason to assume this yet I suspect it may. Eventually I will find out. If so, I will be glad to use an adapter and have the choice for different music. I am guessing that I will stick with no adapter and zero ohms for the vast majority of my music but there would be exceptions.
Again, much thanks for the impressions.