An audio rack is best accompanied with an electric amplified guitar. They are also accompanied best with bass guitars which also require amplification.

Yes

The Clavenet is a keyboard instrument which is an electro mechanical instrument. This means that it requires amplification to produce sound at an acceptable level.

You can play any instrument with the bass clef.

This is just a convention to write notes of certain height in the bass clef.

You can play a piece on an instrument if their diapasons match. Or even it is not so, you can transpose a piece to the diapason for your instrument.

Usually, pieces written for bass instruments (for example, electric bass guitar or double bass) are noted on the bass clef.

An instrument that starts with a b is: a bass clarinet.