It’s been a couple years since I have reviewed iOS-centric hardware for musicians. This is because with each major iteration of the iPad, Apple has altered the dock input configuration thereby rendering an entire ecosystem of equipment relying on that connection port obsolete.  It was painful to send a stack of old IK Multimedia hardware to the landfill a few years ago when Apple upgraded iPads to use the Lightning connector instead of the original 30-pin dock connector.  A similar roundup of older third-party hardware reliant on the Lightning connector will likely happen again late next year if Apple migrates the rest of its future iPad and iPhone devices to USB-C.  Given Apple’s track record, I have resisted investing much additional effort in third-party hardware dependent on proprietary adapters. That is why Eventide’s H9 Max Harmonizer Effects Processor ($699) guitar effects stomp box piqued my interest.  

Related: 5 Best iOS Music Apps for Guitar Players

Rather than rely on a physical port connection to operate and manipulate the effects processor, Eventide’s H9 connects wirelessly via Bluetooth to select, edit, and queue up playlists of effects. This greatly extends the capabilities and ease of use of the device while simultaneously future-proofing it against the whims of Apple’s hardware changes.

Eventide actually offers three different models of the H9 – H9 Core, H9 Harmonizer and the H9 Max Harmonizer. The hardware is identical for each model, with the only difference being the number of unlocked effects in them. The H9 Core offers those curious about effects processing to dip their guitar into the musical waters to begin experimenting with waveform manipulation. The H9 Harmonizer is a good midpoint by offering 99 preset effects to explore. H9 Max is what the product name suggests, offering not only the entire current number of 49 effects algorithms and 500 presets, but also any future releases that become available.

In order to verify ownership of these configurations, Eventide’s free H9 Control app requires the harmonizer’s registration and assignment to an Eventide account. However, somewhat indicative of Eventide’s tight control over its technology, the H9 can only be activated on five devices.  So if you are planning on using the H9 in a mobile environment, be aware of this limitation in case you want to use a couple of old iPhones or iPads to manage the device.

Using the harmonizer is easy.  Effects can be selected by pressing the Tap stomp button on the right. Activating and deactivating the effects is done by pressing the stomp button on the left. Effects can be edited via the center dial and the illuminated buttons below the LED readout. However, while it is possible to manipulate effects this way, major modifications are far easier using the H9 Control app. Simply select the portion of the effect you want to manipulate and slide the touch controls accordingly. Given the quantity of algorithms and presets included in the H9 Max, an inventive and inquisitive musician or sound engineer could spend a lifetime exploring and creating variations of the audio output possibilities.

As for the presets themselves, they competently show off what the H9 Harmonizer can do. Delays, flangers, waa effects, pitch bending, shimmers, auto-swells, and a slew of synth effects turn your guitar into a everything from a classic rocking base to a far out new age synth machine and practically every other musical genre in between. Eventide provides dozens of example videos of the H9 and its effects in action. Eventide also offers also several instructional videos on operating and tweaking the effects on the H9 to help flatten the device’s initially intimidating learning curve.

In addition to the algorithms and effects, the H9 also includes a looper with variable speed playback for single player multi-accompaniment. This turns a single guitar performer into a real-time multi-track loop for awesome studio and live jam sessions. If you haven’t used a looper before, using it effectively requires a precise sense of timing and restraint, as it’s easy to turn a good baseline into a cacophony of offset loops crashing into one another. But when put into the hands of a competent musician, the loops elevate the musical experience to a higher level.


  • Highly versatile effects processor inside a small stomp box package.
  • Audiophiles can spend a lifetime tweaking sound waveforms to their delight.
  • H9 Control app operates wirelessly, removing any need for proprietary adapters to operate.


  • Requires time and patience to invest in sound discovery and experimentation
  • H9 Control app requires H9 account creation/registration before use.
  • Expensive

Final Verdict

The H9 Max Harmonizer is an iOS-friendly tool that represents connected musician hardware done right. The wireless Bluetooth control capability removes proprietary hardware plugs and future-proofs itself against ever-evolving Apple mobile device architecture changes. While the Max model represents a significant musical investment, it is still less than the cost of a decent guitar and will provide a universe of audio options to apply to your performances. Having been a player for decades, I still find it pretty remarkable that so many effects are packed in such a portable, functional package. Being able to quickly dial up and tweak the effects on my iPhone is icing on this musical cake.

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