Producer Tony Visconti used the H910 to achieve the now-legendary snare sound on David Bowie’s Young Americans, and Tony Platt did likewise on AC/DC’s Back in Black. Jimmy Page was an early fan, incorporating the H910 into his guitar rack, and, similarly, Frank Zappa employed it heavily as part of his guitar sound. In 1974, Agnello conceived of a harmony processor but had little idea that he was creating a classic tool for the most successful artists of their generation.

Ideal for vocals, guitars, and horns, the Eventide H910 was invented by then-engineer, Tony Agnello. Music engineered on the H910 became the soundtrack of the seventies and eighties drawing praise and extensive use from a select group of top artists and producers. Early customers included New York City’s Channel 5 putting an H910 to work, downward pitch shifting the audio portion of “I Love Lucy” reruns that were sped up to squeeze in more commercials. Users soon found all sorts of applications, ranging from regenerative arpeggios to bizarre sound design effects to lush guitar or vocal fattening. Yes, vocalist Jon Anderson tested the first prototype. The Eventide H910 Harmonizer effects processor forever changed the complexion of music enabling producers and artists to add texture to their recordings and performances in ways heretofore unimaginable.

The combination of pitch change, delay, and feedback opened up a new world of sonic possibilities which were exploited in the ground-breaking work by artists from AC/DC to David Bowie to Frank Zappa. It featured a two-octave range and up to 112.5 msec of delay. It could be controlled by a keyboard remote control to instantly shift pitch in half steps. It combined ‘de-glitched’ pitch change with delay and feedback. The H910 was the world’s first commercially available digital audio effects device. The Eventide H910 Harmonizer ® was developed by Eventide in 1974.

Eventide h910 harmonizer manual