I'm working on the same problem, with a similar player/equaliser, with similar music. Problem is the output isn't high to start with, and lowering the equaliser settings doesn't help in that respect, but is a good tip. Because of the fairly high bass with the EP-630s, you would have to lower the bass EQ settings quite a lot to make the mids stand out more. I have several much more balanced buds that require no equalisation to suit me, but they're not as good for staying in the ears when moving about. So much for tonal balance. As for muddiness, I largely blame the DACs and then the amps, they seem to work much better with "airier" music. Yeah, the recording compression sure doesn't help, but it sounds good enough on the big system (i.e. Maggies/ACI or Stax), so it's not just the recording's fault here.
I think many compromises have to be made if you want a real small portable system. If I'm sitting still and concentrating on the music, my requirements are much different than if I'm moving around. But yes, I do want to make what I have sound as good as possible. There is no doubt the EP-630s are part of the problem, but you'll have to pay a fair bit more to get their benefits plus a better tonal balance. Based on my basic tests by ear, they have a very noticeable drop in the voice frequency range, about 500-3000Hz it seems to me, with the stock tips (Etymotic tips drastically change and improve this, but they have their own drawbacks). This is unfortunate if you listen to lots of heavy metal/guitar music, and especially so when there are vocals! I will go back and try lowering the bass and highs on the EQ. If you haven't done it, it's a good idea to make a bunch of mp3 files of 10s each of various sine wave frequencies. Save them on your DAP, it doesn't take much room, and you can get a better idea of what you're dealing with.
If you find some buds "similar" to the EP-630 in fit, but better tonally balanced, that work much better with your Creative DAP, I'd sure like to hear about them! I am very limited in what I can listen to around here in IEMs. In fact the "best" was the bottom of the line Shure and it had its own shortcomings for a MUCH higher price. They wouldn't make me significantly more happy. I really want to hear any fancier IEMs before buying, I don't want to start a collection. I have a pretty good idea how the recordings should sound, I have quite a lot of gear here, much known for its relative lack of coloration. I sure don't expect to duplicate the sound from a complete "system" I can wrap my hand around, but I'm willing to go to a certain length to make it better as long as it doesn't get any futzier to deal with in daily use.
