Honestly, this is one of those things that I'm never going to use because it's Web 2.0 and doesn't need to be.
Your core functionality is cool: I definitely would like something that allows me to mix background noises.
But why am I signing up for your service? That has nothing to do with what I want from your app. That just gets in the way of using your app.
Why is there integration with Google Drive? That has nothing to do with background sounds and those permissions aren't happening.
Okay, so you're using the Google Drive integration for your integrated text editor. Why is there a text editor integrated? I have a workflow with a text editor and unless there's something I don't know here, my text editor is better and yours is just going to get in my way. And in fact I can probably name 10 text editors that are better than yours--unless your core product is a text editor, you're probably not going to beat out folks who are actually focused on making a text-editor.
I'd pay As is, this doesn't make it any easier to get good background noise than just keeping a collection of .mp3s on my hard drive, because the interface comes with so much unnecessary cruft. Tools like this don't encourage productivity, they encourage pointless tinkering.