I'm actually still surprised that it turns out that Sonya actually plays a base guitar.
When I first read her talking about it, I was convinced that it was going to turn out to be a classical base, and spark some sort of argument between Erik and Zii that ended with an Apocalyptica-style riff.
What kind of 'classic bass' did you mean? A bass cello?
That said, I think if Sonya played a bass woodwind, it would kinda break the subtlety meter.