Cheap products tend to have less than stellar frequency responses. The NE-7M is an earphone that I couldn't really stand without EQing. There's a rather sizable peak around 5kHz that does make the earphone a little annoying. It's just at a bad spot where it influences a lot of music.
I don't really want to tell you to just spend more money, but really to get a quality level sound, you want to get up into the $150 to $200 price range. Normally a lot of folks are not all that discerning, but you seem to seek more than the average Joe out there. Dream Theater isn't something the average Joe would be listening to either.
I guess step one would be to ask what type of sound are you looking for? What aspects do you want to keep in the NE-7M? What would you change if you could? It is obvious you want a flatter frequency response and an earphone that is better balanced. Beyond that, there's personal preferences in sound. For example, the NE-7M is thick in note where you get a full-bodied presence. Not all earphones are this way, and some can be rather light and airy in nature. You'll have to decide what aspects you like and which aspects you want to change or improve upon. From there, we could point you to something better fitting. I do only suggest that you start looking at a little higher level of a product. Are you wiling to spend $150 to $200 for something really quite good?