Vintage Digital & Analogue Studio Effects

Vintage Digital

Eventide Model H910

Eventide Model H910 Harmonizer®

The Eventide Model H910 Harmonizer was developed by Eventide in 1974. It was the world's very first digital effects processor. It combined ‘de-glitched’ pitch change with delay and feedback. It could be controlled by a keyboard remote control to instantly shift pitch in half steps.


It featured a two octave range and up to 112.5 msec of delay. 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. The H910 was used to create the effects heard on records since the late seventies.

The Eventide Model H910 Harmonizer was the first commercially available audio pitch change device and, in 2007, along with the Thermin, it was inducted in the TECnology Hall of Fame.

While the Eventide Model H910 Harmonizer was ‘digital’ it was 100% software free – it pre-dated the earliest DSP chips by several years. It used digital logic and some of the earliest RAM memory to achieve delay but was, in large measure, an analog beast.

It was designed before high fidelity audio analog to digital converters were available and necessitated that Eventide design its own custom conversion which played a significant part in the sonic quality of the Eventide Model H910 Harmonizer.

The analog sections of the H910, including companding, filtering and analog feedback gave the unit a distinctive sound.

While the user has plenty of pitch change plug-ins to choose from, none have the sonic footprint that results from the analog processing of the original Eventide Model H910 Harmonizer.

Eventide H910

An early prototype of the Eventide Model 910, kindly supplied by Eventide.



Quantization: Unknown
Sampling Frequency: Unknown
Frequency Response: 20Hz-12kHz
Dynamic Range: 90dB
THD: Below 0.2%

Plug-In Options

Eventide H910 Harmonizer
When you purchase the H910 Harmonizer® plug-in, you also receive Eventide’s exclusive H910 Dual Harmonizer®. This version recreates the popular technique of running two H910 units in parallel to create lush doubling and other interesting effects.
Share on facebook
Share on twitter
Share on linkedin
Share on reddit
Share on pinterest
Share on digg
Share on email

Eventide Model H910 Harmonizer® Reviews

Have you owned this product? Let others know what you thought of it.

Community Score


(1 Review)

Build Quality 40%
Sound Quality 40%
Usefullness 50%
Mojo/Funk 80%
Reliability 30%

What other owners say...

The pioneer

By Marcus

Build Quality 40%
Sound Quality 40%
Usefullness 50%
Mojo/Funk 80%
Reliability 30%

This was a new magical device in 1974. We could change pitch without changing the length. The introduction above says it had ‘de-glitch’, it did not. De-glitching was an optional board for the H949. The more pitch change you choose the more glitching you get. I still love it for doubling at the smallest pitch change it will do.

Used it? Leave your rating and review

Leave a Reply

Your email address will not be published. Required fields are marked *

Click to access the login or register cheese
error: Alert: Content is protected !!