What exactly do you mean with "It falls short"? Again, compared to what? Neither the M5, nor the U12t or the U18t have an reference sound. The U18t is the closest of them, but even this one fails so you can not judge if it falls short based on these.
The SE846 has the exact same amount of detail separation as Professional Studio Monitors that are used to make music. So it has the correct amount of detail separation. If that amount is sufficient for you personally is a completely different story but you can not say, it falls short because it has exactly the amount it should have.
How are you able to get neutrality out of an M5?^^ Are you EQing it? It was made to not sound neutral, if it sounds neutral, it is probably broken^^
I never heard anyone call the M5 neutral and i doubt that anyone got it to sound neutral. You buy the M5 for its fun V-Shape sound, you do not want an neutral sound from an M5.
The closest 64audio that comes to an reference sound maybe the A18t or the A18s (i do not remember which one) but this one has a bit too strongly pushed bass. But except for that, they sounded pretty good.
Sadly with the Universal versions, because they are only bought by audiophiles, 64audio decided to push upper mids/lower treble on almost all of these...
Also they are way to expensive for their performance. The IER-M9 easily beats the A18 for less than half the price with only 5 drivers. Not sure what 64audio is doing wrong that they need 18 drivers for an 4-way(!) system. they have 2x8 Drivers playing the exact same sound... what a waste
The M5, is Neutral with a tint of warmth with the right source. so not completely neutral no, but neither is the se846. Totally flat can be boring in the long run, good for recording not so for music.
I hate DAPs like IBasso which gives a tint of annoying focus on the bass (YES it does, or I am sensitive to it). In the past this annoying focus on bass from DAPS as IBasso, Shanling, Fiio (I am talking about the flagship models) have costs me many IEM I sold and money on sold DAP's, because I thought they had some annoying bass issue.
Maybe it is me, but why do so many people want to hear bass this way?, even if it bleeds into the mids, and that constantly push on your eardrums? Yes I like layering in the bass, but not when it pierce out my eardrums? Hence I only like open ear headphones and IEM's that have some pressure relieve.
Now I use a DAP's as de Sp2000 (will be replaced for sp3000), I also use my TT2+mscaler, even my old se200, sounds clean and clear with the M5, or M4 or u12t And many IEM's I didn't like in the past, I actually like a lot now. That's why I said the source is maybe even more important than IEM alone. I can hear that with my u12t and M5, on my tt2+mscaler it is like I bought different IEM's,
But the seperation can be better than the se846 (not saying it is not existent), if I would describe best I would say it is a softdome tweeter (with just a little too much smoothness at some points). You could compare it in speakers to the implementation as dynaudio does it, compared to a sonus faber (flagship) sonus faber is soft but very very airy and clear, where the dynaudio is a little bit more smooth (in this case as the se846, even with the white tube's)
But I myself am very picky on clearness, because at home I listen to Martin Logan ESL electrostats, and that clearness and fast seperation I am looking for in headphones as well.
I am very curious about the IER-M9, never had the change to hear them. with high end IEM it is quite annoying sometimes having to use stealth to find shops that sell them. they are not in price ranged where you think ahhh let's spend 1500 and take a gamble.
