Electro Harmonix HOG2 Review – Best Guitar Synth Octave Pedal?


The Electro Harmonix HOG2 is “an Octave and Harmonic Generator/Guitar Synthesizer that can simultaneously generate multiple octaves and harmonics from your input signal.” Like an EHX POG2 on steroids, the HOG2 can create octave intervals from -2 to +4(!) with a couple 5ths and a 3rd in between. The HOG2 features improved algorithms and sound quality than the original Harmonic Octave Generator and now offers complete MIDI control of every single editable parameter. Improved sound quality is always a good thing, but the unprecedented MIDI control may allow some seriously unique possibilities for guitarists who want to plunge deep in the HOG2. Here’s quick rundown of the pedal’s feature before we launch into our Electro Harmonix HOG2 review.


Sophisticated new algorithms improve the quality of the ten generated octaves and harmonics as well as the Freeze function.

Full MIDI control over all parameters and presets.


A Master Volume for added control and convenience. Volume levels are saved as part of a preset.

10 Controllable harmonic intervals and 7 Expression modes.

Freeze modes holds a note or chord so you can play over it or slide to new notes like a keyboardist playing portamento.

Amplitude envelope controls your attack or decay speeds.

Dedicated resonant filtering with sweepable frequency control.

Separate lower and upper harmonic amplitude envelopes.

Save and recall up to 100 preset programs with the optional Foot Controller (sold separately).

External expression pedal included.

Standard 9VDC 200mA power supply included.

Visit Electro Harmonix for more info about the HOG2 Harmonic Octave Generator.

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Sound & Performance:

I’ve been spending a lot of time with the EHX HOG2 as it’s a seriously inspiring pedal and one I’ve had very high expectations for since its announcement. If you’re a fan of the original HOG or the POG2, you might have an idea of what to expect. But don’t be fooled. The HOG2 really stands alone, not only among other guitar synthesizers or octave pedals, but among any other guitar effect period. While it draws some obvious comparisons to the POG2 (with a nod EHX’s own Freeze and Superego pedals) thanks to its multiple octave voices and sliders, the HOG2 takes this concept above and beyond with some interesting sonic possibilities that cannot be achieved with any other pedal or guitar processor.


The HOG2 has a total of 10 voices which may be used together in any combination. These are -2 Octaves, -1 Octaves, Original, +5th, +1 Octave, +1 Octave + 5th, +2 Octaves, +2 Octaves + 3rd, +3 Octaves, and +4 Octaves. The HOG2’s voices are created by an impressive use of DSP power and are triggered instantaneously with no noticeable latency. Even when playing fast runs it’s amazing how smooth the HOG2 sounds, and the tracking is impressively stable. It’s only when using several voices and playing some pretty complex chords that you may notice a little glitched-out warble, although performance is top tier in most situations and certainly improved over the original HOG. The sheer amount of pristine musical voices the HOG2 can create from a standard mono guitar signal trumps anything else I’ve heard from an octave/synth pedal. The higher range voices are shimmery and ethereal while the -1 Octave and -2 Octaves are smooth and organic sounding. Suspended 4ths, 5ths ,and added 9ths sound especially pleasing with higher voices while the lower octave voices can pull off some authentic bass guitar tones from a standard 6-string guitar.

The Original voice is interesting in that it doubles the Dry Output signal with a digital recreation of the signal. While it may seem redundant at first, the Original voice and Dry Signal each have their uses. You can use the Dry Signal to blend in an unaffected guitar signal to retain the most pure, unprocessed tone. Using the Original voice is primarily for when you plan to pitch shift the voices via an expression pedal (or MIDI control) or affect the voices with the Envelope or Filter section. You can also use the Dry Signal with the Original voice for a doubling effect. Detune the Original voice slightly for a chorus-like, modulated sound.

Electro-Harmonix-HOG2-Review-Best-Guitar-Synth-Octave-Pedal-04And speaking of pitch-shifting, this is where the HOG2 really starts to get interesting. Plugging in the included EHX Next Step Expression Pedal (or any compatible expression pedal) with Exp. Mode set to Octave Bend or Step Bend allows you to achieve some incredibly smooth pitch bends. Step Bend lets you bend one whole step while the Octave Bend sends your pitch soaring up one full octave. I sometimes noticed a slightly “stepped” pitch glide from the original HOG on the Octave Bend setting, but the HOG2 sounds absolutely pristine thanks to its improved pitch algorithms. The really cool part is that you can pitch shift any (or all!) 10 voices up or down a full octave. This means you can take that +4 Octaves voice up to +5 Octaves(!) and the -2 Octaves voice down to -3 Octaves. (To pitch shift the voices down, simply push the Exp. Reverse button.) Just watch your ears and the ears of your pets if you do find yourself brave enough to shift that +4 voice up an octave as it can get intense.

The Expression Pedal has a few other uses that make it an essential live tool for getting the most out of the HOG2 with your feet. The Volume option gives you control over the volume of the generated voices, letting you fade them in and out over your Dry Signal or complete silence the signal when not using the Dry Signal. The Freeze + Gliss is probably my favorite Exp. Mode as this allows you to freeze a note or chord and then play another note or chord and morph seamlessly between the two by rocking the expressional pedal. The effect is similar to sounds produced by the Electro Harmonix Superego Synth Engine except with precise expression pedal control over the rate of glissando. Freeze + Vol lets you take the HOG2 from silence to a sustaining pad-like symphony generated by the notes or chord you’re holding. The Wah Wah mode gives you a filtering effect that is voiced to capture the vibe of a classic wah pedal sound and does so very well. The Filter mode gives you manual foot control of the Filter’s Frequency parameter. This is an awesome way to add some movement and realtime tone-shaping to the HOG2’s voices. You can also set the range of the Filter sweep with the HOG2’s Frequency slider to perfectly suit what you’re playing.

Electro-Harmonix-HOG2-Review-Best-Guitar-Synth-Octave-Pedal-05The Filter is a key component to dialing in the overall tone of the HOG2. It’s such a great-sounding filter that I wish EHX would release it in a stereo MIDI-controlled standalone pedal. Seriously, guitarists and synthesizer fans who like quality filters will dig what EHX cooked up for the HOG2. The Resonance lets you adjust the Q of the filter which emphasizes the cutoff frequency for a potentially aggressive sound. For more subtle filtering just pull the Resonance somewhere around middle and listen for how it affects the peak frequency. The Frequency adjusts the cut-off of frequency of the Filter and will let you round off the high end if those higher voices need to be reined in. You can also get some great bass octave tones by filtering out most of the high end and using the -1 Octave and/or -2 Octaves voices. The HOG2 will give you some incredibly deep sub-bass sounds.

The Envelope brings in some cool Attack & Decay effects. There are separate controls to affect either the Lower or Upper voices. You can either add some Decay for fades and staccato effects or slow down the attack to remove your picking transients or fade in the notes and chords you’re playing. Using different settings for the Upper and Lower voices produces some cool results, too. For example, try setting a quick Decay on the Lower voices and a slow Attack for the Upper voices to create a quick stab of lower notes with a shimmery pad of harmonic octaves on top. Very cool!

The Spectral Gate is also useful when using multiple voices to retain a more focused sound that doesn’t clutter up the mix. It adds an emphasis to the most prominent harmonic of your input signal to generate an even cleaner effect with a bit less high end making it useful as an extra tone-shaping control as well.

The MIDI implementation is one of the biggest improvements to the HOG2, offering complete control of every single aspect of this incredibly deep guitar synth. You can control the HOG2 with any external MIDI controller or even program and automate the pedal from a hardware sequencer or DAW (Digital Audio Workstation) such as Ableton Live. I played a gig using the HOG2 with complete MIDI automation of the pedal and achieved some incredibly complex and precise pitch modulation what would have been impossible to pull off in a live situation otherwise. You can even use MIDI to create some wild pitch arpeggiation spanning +1 to -1 octave with clever automation of the Exp. Reverse and Coarse/Fine tuning parameters. The full MIDI capabilities of the HOG2 make this pedal an essential companion in the studio or as part of a MIDI controlled live rig. The HOG2 will likely become your head-turning secret weapon when you integrate it into such a setup.

The HOG2 can also save and store presets. This is performed most easily with the HOG2 Foot Controller (sold separately) which gives you access to up to 100 of the units presets. Without it you can still save and recall a single preset to the unit by pushing and holding the Exp. Mode button for 2 seconds to save your settings to the current preset bank and pushing and holding the Spectral Gate button until the Preset LED lights up to recall the preset. If you’re using MIDI you can access up to 120 total presets without the need for the HOG2 Foot Controller. When sequencing MIDI to control the HOG2 I just made a single default preset to recall and programmed MIDI for particular songs to automate the HOG2’s parameters as needed.

There’s not much to complain about. Some guitarists might wish the HOG2 Foot Controller was included, perhaps even instead of the expression pedal. Also, while the algorithms sound extremely good, you may still notice some jiggly anomalies when using the higher voices with 2nds, 3rds, and 7ths. The Filter sounds so good that you may wish, like me, that it had its own in/out to be routed anywhere in your signal chain, but of course that doesn’t take away from how awesome the Filter sounds within the HOG2. (I’ll just keep crossing my fingers for an Electro Harmonix MIDI-controlled stereo filter pedal.) There’s also the matter of size, as this pedal (and its accompanying Foot Controller and Expression Pedal) take up a lot of room on your pedalboard. But if you like octave effects and guitar synthesizer pedals, you may not mind clearing some room to make the HOG2 the new centerpiece of your pedalboard. The HOG2 is certainly one of the most ambitious guitar pedals from EHX and one that will inspire the bold guitarists who tap into the sonic power it offers.

Let’s see the final result.



The Electro Harmonix HOG2 is quite possibly the most inspiring guitar synth pedal I have ever played. Its array of 10 voices combined with powerful Envelope and Filter sections provide an unprecedented amount of customizable textures for some of the most surreal sounds you’ll ever hear generated from a guitar. While the HOG2’s included Next Step Expression Pedal gives you plenty of realtime control possibilities, it’s the pedal’s complete MIDI integration that pushes it over the top as a wellspring of guitar octave synthesis inspiration. Until the HOG3 hits the scene the HOG2 will likely reign as the best guitar octave synth pedal in the digital realm. In the right hands this pedal will create some legendary sounds.

That concludes our Electro Harmonix HOG2 review. Thanks for reading.


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