well, you could try spacing the different "parts" out more. like make sure they don't cross back and forth over eachother; in other words treat a note on your middle voice like a wall and the other parts must stay above that part or below it, they aren't allowed to cross the boundary that it's creating.
of course, you don't have to do this, but it's one way to create a less blurred sounding arrangement, where everything has its own definite space. stereo panning is of course another way to achieve this, making sure each instrument has its own space in the stereo field so that it can be identified from the rest. and yet another is by changing the timbre of each instrument (or in this case synth) enough that it sounds like an entity distinct from the rest.