Hey EW
Re: audio file - nice! You got a cool Blade Runner vibe going there. 
I did notice what you mentioned, though, the hum in the first few seconds before your synth kicks in. Mine in the setup using the interface to PC sounds very similar, although probably relatively louder still, since, with an extended range bass, I can only decrement gain stages so far before the thing sounds gutted and too quiet. Interesting that there might be an app to remove the hiss; maybe Izotope’s Ozone product or something like that? For me, I need a solution that resolves all of this before I get to a recorded track; I just hate hearing that noise even while I’m headphone monitoring without recording.
/fp