Instruments / Backline Amplifiers
The amplifiers that musicians typically have on stage (behind them) to amplify the sound of their instruments. Examples: Guitar amps, Bass amps, Keyboard amps.
Some musicians (Electric Guitarists especially) treat their backline Amplifiers as part of the instrument. For these folks there is just no substitute for that sound. Micing the speaker cabinet and amplifying it through the Bose Personalized Amplification System™ is a completely viable way to let them create the tone and share it with the room.