John Baylies is a sousaphone player. The sousaphone has been around since 1893, but Baylies is famous for playing a far more advanced version called the SousaFX. This electronic accessory lets him control audio effects that give his instrument abilities that you'd never expect to hear in a classical orchestra, such as stutter and tremolo. What you see him manipulating with his left hand is actually a PlayStation 4 controller.
Baylies performs with Sousastep, an improvisational group based in Boston. You can listen to their work on SoundCloud.
The pulsating LED lights are a nice accent and Baylies has helpfully provided instructions on how to install them.
-via Massimo