I think a lot of Head-Fi'ers have replied back to you in my short absence.
First things first, this is just some extra info for everyone: flat frequency is
NOT neutral. That is just a mathematical ideal. Though everyone has an idea of what neutral is, neutrality is usually very small increases in specific areas of a frequency range so that various sounds sound
'natural' to
human ears. Etymotic and Phonak almost got that right with their earphones for example.
Musicality is different; this is where we humans prefer to hear something fun, in specific areas of a frequency range.
Though recorded music is one thing, it is near impossible to replicate it as neutral, so yes, one could try to playback the recording as recorded, but as neutral is different to everyone, flat-frequency is not the answer. Of course, many of us like to hear a recording the way we like to, and will get gear to do just that.
Therefore, to me I think the the DP-X1 is extremely neutral with small emphasis on coherency: speed of transients, a very small bump in mid-bass, ever so slightly upper-mids, and extended treble but not as sibilant as I expected.
This is my impression using the DP-X1 in high gain, ACG balanced mode, with my Audeze EL-8 Titanium headphones and DHC Molecule Elite 22 Silver (22AWG) 4-Wire balanced cable.
When I tested my Meze Headphones 99 Classics (normal gain, unbalanced mode) with stock cable, the DAP sounded different; warm, musical, a tad indistinct in bass yet still lovely. I attribute that to the DAP having little sonic colourisation.
Ditto same experiment (high gain, unbalanced) on my AKG K 712 with DHC Molecule Prototype 25AWG copper cable; heard some sibilant peaks, slightly spotlighted vocals/mid-range, and clear bass notes but not much oomph.
My Heir Audio 4.Ai IEM's (normal gain, ACG balanced) with DHC Molecule Symbiote Fusion 8-Wire balanced is very similar to the AKG K 712 but less soundstage, less coherency and more focus on individual instruments or sounds.
In many ways, the DP-X1 is not a 'warm' or 'tubey' DAP, which is why some users opted for the Astell and Kern or Questyle QP1R.
So, with that in mind, because of the neutralish sonic character of the DP-X1, it allows each of my headphones to display their own characters.
Thus, any headphone you plug in will sound great on this DAP, as the DAP does not colour the sonic picture too much or at all (in my opinion).
What the DAP
does do is give excellent clarity, hardly any grain, amazing detail and texture, great soundstage in height and depth (though more width would have been nice), and is super fast on transients.
Regarding EQ, as
@Laird
has said in his post (
here), one should never boost, just cut/attenuate. By boosting you massively reduce headroom and dynamics, but reducing frequencies, the dynamics are impacted upon less.
This is something I learned from when I studied Music Technology years ago and did PA work.
Having said that, I echo that the EQ on the DP-X1 may not scale well if boosting, it clips, but that is as far as I can comment upon as I do not use EQ on the DP-X1.
I think the DP-X1 is stellar and worth investing in, but only a demo of it can really tell you the truth.
If the DAP does not sound right to you, I strongly recommend Questyle QP1R, almost the opposite end of the DP-X1 yet still incredible for music! Just remember, you will lose out on the other benefits that the DP-X1 offers outside of sound quality.
EDIT:
Added some extra bits, specificaly the DP-X1's sonic capabilities.
