Here’s a rough transcription of Steve Swallow, one my favourite bassists, playing on the album Three Guys with Lee Konitz and Paul Motian. (Dreamy band or what?). It’s a Konitz composition over It’s You Or No One. So far, I can’t find it online (tiny sample in this article) but I’m reliably informed it exists on youtube.
Anyway, here is the unison line that ends the tune:
And here it is played in somewhat Swallow-y style — very light roundwounds with a pick and loads of tone rolled off:
Connoisseurs will know that the pick should really be copper, and the bass a semi-acoustic with a piezo somewhere, strung E-C, etc.