I get the steampunk kinda vibe I think you’re going for, but it seems to me to be unnecessarily complicated. Why have an eq pedal on the bass body and is the speaker functional?
*Very *loosely. A microphone is something we usually think of as picking up sound transmitted through the air or other medium by resonating in sympathy with that sound. Microphones work on two basic principles: the “reverse speaker” one described by BubbaDog, and the piezoelectric mic, which uses a crystal that generates a current when it vibrates.
A pickup does not vibrate; it picks up changes in its magnetic field caused by vibrations of ferromagnetic metal and produces current as a result. An amp amplifies the resulting current into something that we perceive as sound.
In the passage you quoted I would grant literary license to the writer. Just this once. 
It’s my first bass guitar! I de-fretted it years ago while I played bass in a band. Then I realized I could just mod it and make something fun, as I still have another bass (Alembic spoiler ((I don’t play much anymore). It has an active amp in it, connected to the speaker and through, with power starve and volume. It has feedback loops, internal and external, all connecting the various pickups and the tape head on the neck. The pickup on the horn is for noise with f.ex. a scrape for paint, spoon, steel wire, also feeding into the feedback loops. The eq connects it up so control the feedback in the guitar without bending down. And finally flip switches for loops, a general volume and a tone knob.
That was a mouthful.
That thing is a bass-full.
IT’S ALIVE!!:eek:
A pickup is a kind of transducer, which is a part of a microphone. It’s the part of the mic where the electronic part of the action happens, so to speak. So as long as you think of the body and strings as the (ok, I can’t think of a more generic word) diaphragm, close enough!
SQUEEEEEEEAL! Plumpudding, I don’t want to do that to my Epi EB-3, but I so dearly wants to plays whatever you have done to yours. Mail it to Texas. I promise to mail it back someday.
Oh I forgot, you can also play kinda clean.