Or making some unhappy setter Heel, or listening to a bleak
A setter is a kind of dog. So, the woman could be telling the dog to heel (slow down and walk next to her).
Or she could be listening to a bleak… something (looks like we'll find out what exactly on the next line).
This is more of what's she isn't doing. Our speaker has quite the imagination!
Lecture on Schoenberg's serial technique
Biography note: Schoenberg was an Austrian composer who eventually moved to the U.S. in 1934.
The "serial technique" Wilbur brings up here is just his style of composing music—using altered repetitions of a specific series of sounds.
The lecture part of this line brings to mind school, specifically college. This is the second time our speaker has imagined this woman in school or studying. Maybe they are college age and skipping class?
Isn't this better?
Woo hoo! We're out of the daydream. Maybe we'll find out what they're actually up to.
Still though, our speaker is holding out on us. He just says isn't "this" better, but we're still not sure what "this" is.