Disco Tech

Technology that heavily involves music, usually either activating things, or somehow being a power source.

'''This cannot be music for puzzle solving, or things like that. It has to be technology using music.'''

Name is a pun on the term "discotheque".

Magic Music is the magic counterpart to this trope.

Compare The Power of Rock, Band Land.

If the music is used as a weapon, you're looking for Musical Assassin.

Anime and Manga

 * Senki Zesshou Symphogear features ancient power armours that run on "phonic energy", also known as singing.

Film

 * Major Domo in Captain EO.
 * Duran Duran's "Orgasmic Organ" in the Barbarella movie.
 * Willy Wonka has a door with a musical lock, opened by a piece by Rachmaninoff.
 * Masters of the Universe has the Cosmic Key, a device that is capable to open portals the destination of which depends on the notes that are played on it.

Live Action Television

 * The Star Trek: The Original Series episode "The Paradise Syndrome" features a potentally world-destroying asteroid held at bay by a repulsive field

Video Games

 * In Chrono Trigger, the cathedral of the Middle Ages features doors that can be opened by playing a nearby organ.
 * In Mother 3, you can perform combo attacks by pressing the A button to the beat of the battle music. This feature is described in-game as a "sound battle".

Web Comics

 * The Andrew Hussie Web Comic And It Don't Stop.
 * Agatha Heterodyne, Girl Genius, controlled her circus clanks through music.

Western Animation

 * The lost city of Tinnabula from the two-part Tale Spin episode "For Whom the Bell Klangs".
 * A Disney Silly Symphonies short "Music Land" involved a war between anthropomorphic violins and horns, playing their music as weapons.
 * There's an episode of Batman the Animated Series which involves playing the beginning of "Ode To Joy" to unlock the secret room.
 * The girl's voice in Rock and Rule was significant to help Mok with his summoning spell.

Real Life

 * While not strictly musical, the principle behind acoustic refrigeration relies on resonating sound. The effect is something close to a real-life version of Maxwell's theoretical demon.
 * The Zeusaphone is essentially a Tesla coil that shoots lightning, tuned in such a way as to produce musical notes.