Amplitheater

A theater designed to host amplified sound-based performances, including live music, comedy, lectures, and other speech-centric presentations.

The term is a portmanteau of 'amplified' and 'amphitheater'.

What an amplitheater is not:
• A traditional/classical concert hall (where a symphony orchestra would play) is not an amplitheater. These buildings are made to naturally enhance and project the sound of unamplified acoustic performances, and often have little to no amplification equipment.
• Almost all movie houses today have the infrastructure to host sound-based entertainment too, so they could be considered amplitheaters. However, a true amplitheater is purpose-built to support the best listening experience, with optimized room acoustics and a comprehensive sound reinforcement (PA) system.

My favorite rock band is playing at the amplitheater tonight!