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Eventide H90 Harmonizer

Multi-effects Pedal By Paul White
Published February 2023

With its astonishing array of new and cherished effects, Eventide’s ‘everything pedal’ should appeal to guitarists, synth heads and mix engineers alike.

Eventide’s new H90 Harmonizer isn’t exactly inexpensive as effects pedals go, but you do get an awful lot for your money. It’s a very powerful multi‑effects pedal that can best be thought of as being the equivalent of two of their H9 Max pedals (it has two processing engines, each of which can run its own algorithm) but with considerably more processing power, a significantly extended set of algorithms, and some other new features.

Employing ARM‑based DSP architecture related to that of the flagship H9000 Harmonizer, the H90 has enough processing power to run very low‑latency, true polyphonic pitch‑shifting algorithms based on Eventide’s SIFT (Spectral Instantaneous Frequency Tracking) technology; this sidesteps the warbling artefacts that you hear from devices using conventional ‘loop and crossfade’ techniques. Improvements have also been made to the existing pitch‑shifting algorithms. As with the H9, there’s also the option of software editing on a Mac or Windows PC using the free H90 Control software, plus there’s Bluetooth support — though at the time of writing the H90 Control app for mobile devices had not yet been released.

The H90 ships with updated versions of all the algorithms from the H9 Max bundle, but adds several new effects, named Polyphony, Prism Shift, Bouquet Delay, HeadSpace, Weedwacker, Even‑vibe, Wormhole, Instant Flanger, Instant Phaser, and SP2016 Reverb. Several of these are completely new, but as their names imply the last three are based on established high‑end Eventide products. Eventide also say that, as was the case with the H9, new algorithms will be made available as they’re developed. (Top of my personal wish list would be some granular delay effects!) It’s not just about the new effects, though, and Eventide tell us that “the H90 includes new features and enhancements, such as quantisation and improved pitch‑tracking, as well as additional features previously only available on the dot9 pedals and plug‑ins.”

Get With The Program

There are over 99 factory Programs, and the same number of user Programs. (By default the latter are the same as the factory ones.) A Program comprises the two algorithms (one for each engine), their settings, their routing and other relevant parameters, and you can access Programs that aren’t in the user list using the pedal’s Programs menu or the H90 Control app. The user can also create Playlists, which arrange multiple Programs in a sequence that’s convenient for a live show — again, different Playlists can be accessed either from H90 Control or from the pedal, this time using the System menu. Note, though, that you can only create new Playlists using the software.

The two engines can be configured to process the signal in series or in parallel, with the option of ‘spillover’ between Programs when changing presets, and with a choice of relay or buffered bypass. There are also various I/O configurations, and these include a choice of line or instrument level operation, as well as configuring the additional I/O as two mono inserts (or one stereo insert) that can be positioned anywhere in the signal chain — this makes the H90 equally suitable for use on a guitar pedalboard, in a synth rig, or for more general use in a studio’s recording/mixing setup. A Dual Path mode allows the processing of two independent stereo signals at the same time, and if you need more real‑time control there are two expression inputs for pedals, and there’s support for auxiliary switches with up to three buttons. The H90 also ‘understands’ CV signals, which again should mean this pedal holds plenty of appeal for modular synth fans. Meanwhile, guitarists should be pleased to find a tuner is built in, since it means they can also ditch their existing tuner to free up pedalboard space.


The casework has a similar styling to Eventide’s H9, with its all‑metal upper casework finished in crisp white paintwork on a black folded‑steel base, but is wider in order to accommodate the additional controls and its larger monochrome OLED display. All the audio connections are on the rear panel, with LEDs to indicate which inputs and/or outputs have been set to line level rather than instrument level. There are rather a lot of quarter inch jacks, because in addition to the expected mono/stereo inputs and outputs there are two pairs of I/O jacks for use as insert sends and returns, or as the additional inputs and outputs required for a Dual Path setup.

Two further jacks accommodate expression pedals or switches, and there’s a USB‑C connector for loading software updates and for carrying MIDI data. Conventional five‑pin MIDI in and out/thru connectors are located on the left of the pedal’s case. A standard barrel connector accepts external 9 to 12 V DC supplies rated at 1A or above — a suitable power adaptor is included, but this approach means it can be used with a variety of pedalboard power supplies if you prefer. Note, though, that it’s a centre‑positive connection, so if using a pedalboard PSU (which must have isolated outputs), you’ll need to use a polarity‑invert cable.

As well as the expected input/output jack pairs, another pair caters for inserts or the special Dual Path configuration, while others support external expression pedals, switches and CV signals.As well as the expected input/output jack pairs, another pair caters for inserts or the special Dual Path configuration, while others support external expression pedals, switches and CV signals.

When editing the routing, the signal path is shown on screen graphically, which makes it very easy to follow. Four pairs of red and green LEDs, placed above the display, function as simple input level meters, showing signal present and ‘too hot’, while a blue status LED indicates when Bluetooth is being used.

All five knobs are push‑turn encoders. The two larger ones are for Select/Bank and Perform, and these have red, illuminated rings to indicate what mode is active. The remaining three are smaller and located below the display. These are generally used for selecting and adjusting on‑screen parameters. A pair of buttons on the left select the edit modes for Programs, Routing and System settings, while to the right a pair of buttons access Presets and Parameters. Both are used together to set the tempo, speaking of which, both tap‑tempo and MIDI sync are supported.

The H90 offers both Select and Perform play modes, which determine how Programs are accessed. In Select mode, the Program Select control scrolls through the entire Playlist of Programs, while in Perform mode, your Playlist appears as multiple Banks of three consecutive Programs. You can load these Banks using the footswitches, or step through them using longer switch presses. It’s also possible to programme an aux switch or a MIDI controller to control the Bank Up or Down functions.

In Perform mode, the footswitches are used to access user‑programmable performance parameters, with the footswitch assignments including things like tap‑tempo, Active/Bypass, Momentary Active, three separate Hot Switches and algorithm‑specific parameters. You can have up to six assignable parameters per Program, so can make good use of your external pedals or switches. As with the H9, the Hot Switch functions allow the adjustment of multiple parameters using a single control. For example, an expression pedal or knob can be used to morph between settings, and the Hot Switches can call up alternative sets of parameters for the current algorithm.

Each footswitch has an illuminated button above it that lights red, green or white depending on the mode. In Select mode you can cue and load Programs from a Playlist, which is set up in the System Menu Global page. Select mode has two views, Program Select and Bank Select, and the Select knob button toggles between them. When working from a Playlist, the left footswitch activates the pre‑selected Program while the other two switches are used to scroll up or down the Playlist. In Program Select mode, the display shows one Program at a time; the Program’s two algorithm and Preset names will be displayed while scrolling through the Playlist. There’s also the option to explore and edit the individual algorithms and to save your own user presets for these.

Because of the different operation modes and the fact that some controls change their function according to which mode you are in (and some operations require a long knob press), you will need to go through the manual, but once you’ve got your bearings, operation soon becomes second nature.

If you’re one of those for whom deeper edits using the front‑panel controls and screen tends to make your head hurt, there’s relief in the form of the aforementioned Mac/Windows H90 Control app, which can be downloaded from Eventide’s website. This provides a more immediate method of algorithm and Program editing, as all the relevant controls are presented as knobs and switches. Note that while the H90 Control app is free, you’ll need to register your H90 before you can download it. As I said above, the mobile device version of the app was not yet available at the time of this review, but when it arrives that should make it easier to perform such edits when you’re out and about.

The excellent quality of the new SIFT pitch‑shifting algorithm is immediately obvious...


The H90 Control software — the desktop version is shown here but a mobile app will follow — makes deeper edits rather easier than when using the front‑panel controls.The H90 Control software — the desktop version is shown here but a mobile app will follow — makes deeper edits rather easier than when using the front‑panel controls.

The H9 had some great algorithms but they’ve been upgraded for the H90, so as to take advantage of the significantly more powerful processors. They include a range of reverbs, including the fabled Black Hole, a wealth of delays with modulation capabilities, pitch effects and a host of modulation effects that include a useful rotary speaker and a convincing Uni‑Vibe, as well as flexible versions of all the familiar effect types. There are also distortion‑based effects taken from the H9, though more have been added too. The Weedwhacker, for instance, is based on two Tube Screamers connected in series. For any effects that include polyphonic pitch extraction and shifting, the excellent quality of the new SIFT pitch‑shifting algorithm is immediately obvious, though Eventide’s ‘standard’ pitch shifting process is still available, and sounds as impressively smooth as ever where it’s used.

There are also faithful emulations of Eventide’s old H910 and H949 Harmonizers, which aficionados of vintage effects should love, and the excellent Instant Flanger, Instant Phaser and SP2016 Reverb have already established their credentials as recreations of their hardware counterparts. Then we have tuned resonators, the familiar Crystals, a sumptuous Shimmer reverb, reverb/delay hybrids, EQ plus compression, HotSawz (a mono pitch‑tracking synth with six stacked oscillators), and Synthonizer, another tracking synth that offers both analogue synth‑style and theremin‑like sounds, complete with envelope attack control for each of its two voices and its sweepable filter.

Prism Shift is rather special, as it generates three arpeggiated voices from a single chord, again using Eventide’s SIFT polyphonic pitch‑tracking algorithm. Another algorithm that exploits this technology is Polyphony, a dual shifter that incorporates filtering to keep the shifted voices sounding as natural as possible. The voices each have their own delay effects, with variable feedback, and if you wish the shifters can be used inside the feedback loops to create pitch‑spiral effects. There’s also a stereo looper, with the option of MIDI Clock sync offering between one minute and eight minutes of recording depending on the audio quality selected.


This all sounds great, doesn’t it? And it is. But simply describing the algorithms doesn’t really do the H90 justice. For example, I mentioned earlier that there doesn’t seem to be a dedicated granular delay in its armoury. But while I’d love for one of these to be added, some of the factory Programs already create some wonderfully lush ambient soundscapes that rival those produced by granular delay devices and plug‑ins — and there’s plenty of scope for tweaking them too.

I want to end by stressing that, despite its form factor, the H90 isn’t a guitar‑only stompbox. It can work its magic on just about any source. Not only does it offer proper ‘studio quality’ reverbs, delays and modulation effects, as well as the more creative effect combinations, but its line‑level options mean it can also fill in for a studio rack processor (or two!), and the MIDI and CV support will open up a world of possibilities for modular synth enthusiasts.

If you do happen to be a guitar player, and are frustrated that synth players get all the cool sounds to play with, there are treatments here, such as the Cinematrick and Zero Gravity Programs, which transform the humble guitar into a kaleidoscope of tonal colours to rival anything that comes out of a keyboard synth. And if you have a synth that lacks character, the H90 can turn it into a thing of wonder. I could go on — but this is one pedal you really need to hear for yourself.  


  • Excellent sound quality.
  • A huge range of effects types.
  • Smooth polyphonic pitch‑shifting.
  • Flexible I/O options.
  • Friendly software editor.


  • The H90 may seem expensive for a pedal, but the price is more than reasonable when you realise what you get.
  • Mobile app not available at the time of this review.


The H90 is a serious, studio‑grade, dual‑engine effects machine that can be used at instrument or line levels. It comes with an impressive range of effects algorithms, with the promise of more to come. For those into more experimental sounds, to hear one will be to want one.


£999 including VAT.

Source Distribution +44 (0)20 8962 5080


Eventide Inc. +1 201 641 1200.

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