Eventide H9 Harmonizer Effects Processor

The H9 is controlled through a simple, one-knob user interface: X, Y and Z buttons and a large jog wheel/switch provide parameter access in place of dedicated parameter knobs¹. It also connects wirelessly via Bluetooth to iPods, iPhones and iPads for editing, and can run all of Eventide's stompbox effects². A built-in tuner provides better performance, accuracy and speed than most standalone tuners, in Guitar World's reviewer's experience¹.

Power and connections

The original H9 runs on a 9 to 12VDC, 500mA center-positive power source and ships with a nine-volt adapter, so there is no battery option¹. Note the center-positive polarity, which is the opposite of most pedals and rules out a standard daisy chain.

Connections are generous for a stompbox. The pedal has pairs of stereo 1/4-inch input and output jacks, side-mounted MIDI in and out/thru jacks, an expression pedal jack, and USB for connecting to a computer¹⁷. Real-time controls and preset selection are controllable over MIDI, though Eventide's own guidance was that a few settings need to be changed for the pedal to work with an external MIDI controller⁸. The H9 Max adds assignable external switch functions (Tip, Ring or Tip+Ring) on its expression jack, so a two-button auxiliary switch can drive it⁹.

The Gen 2 updates the connection set: 2x 1/4-inch TS inputs, 2x 1/4-inch TS outputs, USB-C for the Eventide Control app, 5-pin MIDI I/O and an expression pedal input¹¹¹. It takes 12V power, so it can be incorporated into a board and used with any modern high-quality power source, as Premier Guitar's demo put it¹².

H9 Max and the Gen 2

The H9 line came in three versions: the H9, the more economical H9 Core, and the H9 Max¹³⁴⁷. The Core delivered the sounds of Eventide's H910 and H949 harmonizers at a lower entry price¹⁴. The Max came pre-loaded with everything from all four Eventide stompboxes plus the H9-exclusive algorithms, which Barry Rudolph described as "a studio processor in a stomp box" carrying "the seminal Eventide Harmonizer-based effect patches heard on hit records spanning the last four decades"¹⁵. Individual algorithms were priced at $19.99 for H9 and H9 Core owners and free for the H9 Max¹³.

The H9 Harmonizer Gen 2, announced in June 2026 and released globally on June 24, 2026 at $599 MSRP, is built on the same modern processing architecture as the H90 Harmonizer⁶. It carries 74 algorithms, including the full libraries from both the H9 Max and the H90¹⁶¹⁷. Its outputs are labeled Left Out and Right Out¹⁶.

What reviewers said

Guitar World's original review found that "the H9 fully lives up to the company's well-deserved reputation, delivering pristine, noise-free effects with luxurious sheen, depth and detail"¹. MusicPlayers.com's reviewer called it a complex digital signal processor that upholds Eventide's reputation, and reported excellent support: an email was answered in hours and a phone call in under five minutes, with an active support forum⁷⁴. The same site noted a practical drawback of the original hardware: it took nearly a full second to load some of the algorithms⁷.

Of the Gen 2, Guitar World's reviewer rated the sounds five stars and called them "amongst the best quality effects of any multi-effects I've tried"¹⁸. MusicRadar's Gen 2 review lists its connectivity and algorithm count among its strengths¹¹.

Premier Guitar's Tom Botwin demoed the Gen 2's perform mode, which "allows you to manipulate the effects in real time and you can customize this in a variety of different ways," with or without an expression pedal¹².

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