The Electro-Harmonix Intelligent Harmony Machine is an Electro-Harmonix octave pedal, currently around $190.85. Close alternatives include the EarthQuaker Devices Rainbow Machine and the Meris MR Hedra. It pairs well with the PRS MT100 and the Orange Rockerverb 50 MkIII 2-Channel 50W Head.

Electro-Harmonix Intelligent Harmony Machine

Electro-Harmonix · pedal

The Electro-Harmonix Intelligent Harmony Machine is a polyphonic pitch shifting harmonizer that generates musically correct harmonies based on a selected key and scale, automatically following your playing to add diatonic harmony voices. It can produce smart two part harmonies, octaves and pitch shifts that stay in key, plus detune and pitch effects, with controls for key, scale and harmony interval. From classic dual guitar harmony leads to lush layered textures, it tracks polyphonically and cleanly. It suits rock, metal, prog and experimental players who want intelligent, in key harmony lines, harmonized leads and pitch effects without manual interval juggling, in a compact and capable pedal.

What stands out

  • “the electro-harmonix intelligent harmony machine is a polyphonic pitch shifting harmonizer that generates musically correct harmonies based on a selected key and scale”

    — from the listing

  • “from classic dual guitar harmony leads to lush layered textures”

    — from the listing

  • “It can produce smart two part harmonies, octaves and pitch shifts that stay in key, plus detune and pitch effects, with controls for key, scale and harmony interval”

    — from the listing

  • “The Intelligent Harmony Machine is a smart polyphonic harmonizer that adds diatonic, in key harmony voices based on a chosen key and scale, tracking your playing to generate musically correct harmonies, octaves and pitch shifts”

    — from the reviews

  • “Its most praised qualities are the intelligent in key harmonies, the clean polyphonic tracking and the ease of creating harmony parts”

    — from the community notes

  • pitch
  • lead
  • harmonizer
  • clean
  • tracking
  • musical
  • octave
  • rock
$190.85View on Reverb

Price updated Oct 25, 2026

Genres the Electro-Harmonix Intelligent Harmony Machine is commonly used in

  • Metal
  • Rock
  • Experimental
  • Electronic
    citedInferred from shared tonal signals, not a stated genre tag.

Amps that pair well with the Electro-Harmonix Intelligent Harmony Machine

PRS MT100

PRS

17% match

PRS MT100's own mid-forward character is the real reason this is worth trying

Comes later in the signal chain

Orange Rockerverb 50 MkIII 2-Channel 50W Head

Orange

17% match

fills a frequency gapFills in a frequency range the other side doesn't cover, instead of piling more onto what's already there. (transparent → mid-forward)

Orange Rockerverb 50 MkIII 2-Channel 50W Head leans toward full, and that's a real, usable character to pair with

Comes later in the signal chain

Synergy SL2 Module

Synergy

tonal match

Comes later in the signal chain

Put Synergy SL2 Module after Electro-Harmonix Intelligent Harmony Machine

Mesa/Boogie JP-2C John Petrucci Signature 60/100-Watt

Mesa Boogie

tonal match

Comes later in the signal chain

Mesa/Boogie JP-2C John Petrucci Signature 60/100-Watt goes after Electro-Harmonix Intelligent Harmony Machine in the chain

Egnater Tweaker 88 Head

Egnater

tonal match

Comes later in the signal chain

Egnater Tweaker 88 Head goes after Electro-Harmonix Intelligent Harmony Machine in the chain

Ceriatone 2202H

Ceriatone

tonal match

Comes later in the signal chain

Put Ceriatone 2202H after Electro-Harmonix Intelligent Harmony Machine

Carol-Ann OD-2R

Carol Ann

tonal match

Comes later in the signal chain

Carol-Ann OD-2R goes after Electro-Harmonix Intelligent Harmony Machine in the chain

Marshall Studio JCM900 SN20H

Marshall

tonal match

Comes later in the signal chain

Marshall Studio JCM900 SN20H goes after Electro-Harmonix Intelligent Harmony Machine in the chain

Pedals that stack with the Electro-Harmonix Intelligent Harmony Machine

Electro-Harmonix 1973 Violet Ram's Head Big Muff Pi V2

Electro-Harmonix

17% match
$114.30via Reverb

fills a frequency gapFills in a frequency range the other side doesn't cover, instead of piling more onto what's already there. (transparent → mid-forward)

Electro-Harmonix 1973 Violet Ram's Head Big Muff Pi V2's own fuzzy character is the real reason this is worth trying

Comes later in the signal chain

Wren and Cuff Box of War OG

Wren And Cuff

16% match
$298.33via Reverb

Wren and Cuff Box of War OG's own full character is the real reason this is worth trying

Comes later in the signal chain

Malekko Electro-Harmonix Memory Toy Analog Delay

Electro-Harmonix

6% match

sits in the right chain slotPlaced for where it does its job cleanly in the chain, not for a tonal interaction with the anchor.

Run Malekko Electro-Harmonix Memory Toy Analog Delay after Electro-Harmonix Intelligent Harmony Machine in the signal chain, where it won't crowd Electro-Harmonix Intelligent Harmony Machine — goes in the amp's FX loop (or last, into a clean amp)

Comes later in the signal chain

Fender Hammertone Reverb

Fender

6% match
$85.01via Reverb

sits in the right chain slotPlaced for where it does its job cleanly in the chain, not for a tonal interaction with the anchor.

Run Fender Hammertone Reverb after Electro-Harmonix Intelligent Harmony Machine in the signal chain, where it won't crowd Electro-Harmonix Intelligent Harmony Machine — goes in the amp's FX loop (or last, into a clean amp)

Comes later in the signal chain

Dr. Scientist Frazz Dazzler V2

Dr Scientist

tonal match
$204.36via Reverb

Comes later in the signal chain

Put Dr. Scientist Frazz Dazzler V2 after Electro-Harmonix Intelligent Harmony Machine

Warm Audio Jet Phaser

Warm Audio

tonal match
$109.01via Reverb

Comes later in the signal chain

Put Warm Audio Jet Phaser after Electro-Harmonix Intelligent Harmony Machine: modulation reads clearest once the core tone is set

Donner Big Mouth Distortion

Donner

tonal match
$29.95via Reverb

Comes later in the signal chain

Put Donner Big Mouth Distortion after Electro-Harmonix Intelligent Harmony Machine

Demon FX Gladiator Double Preamp Just

Demon Fx

tonal match
$64.88via Reverb

Comes later in the signal chain

Put Demon FX Gladiator Double Preamp Just after Electro-Harmonix Intelligent Harmony Machine

Cheaper alternatives

Electro-Harmonix Pitch Fork Plus

Electro-Harmonix

63% similarity
$171.68via Reverb

Shared character: pitch modulation, single rig, tight tracking

Electro-Harmonix Slammi Plus

Electro-Harmonix

57% similarity
$125.78via Reverb

Shared character: pitch modulation, tight tracking, one octave

TC Electronic Quintessence Harmony Intelligent Harmonizer

TC Electronic

48% similarity
$129via Reverb

Shared character: lead

T-Rex Quint Machine

T Rex

43% similarity
$165via Reverb

Shared character: lead

Boss PS-6

Boss

42% similarity
$139.99via Reverb

Shared character: pitch modulation, tight tracking, one octave

Behringer Octavia Octave Fuzz

Behringer

42% similarity
$87.40via Reverb

Shared character: tight tracking, one octave, clean

Boutique & premium upgrades

Alexander Pedals Fever Pitch

Alexander Pedals

56% similarity
$299via Reverb

Shared character: pitch modulation, one octave

Meris Hedra Shifter

Meris

48% similarity
$299via Reverb

Shared character: pitch modulation, tight tracking

Mu-Tron Octave Divider

pedal

47% similarity
$600via Reverb

Shared character: tight tracking, one octave

Roger Mayer Octavia Classic

Roger Mayer

42% similarity
$399via Reverb

Shared character: each note, tight tracking, one octave

Similar charactersee all similar tone character →

EarthQuaker Devices Rainbow Machine

EarthQuaker Devices

60% similarity
$229via Reverb

Shared character: pitch modulation, single rig, tight tracking

Meris MR Hedra

Meris

56% similarity

Shared character: pitch modulation, one octave, lead

Walrus Audio Luminary

Walrus Audio

48% similarity

Shared character: tight tracking, one octave, clean

DigiTech Whammy Pitch-Shifting Pedal

Digitech

46% similarity
$184.29via Reverb

Shared character: pitch modulation, tight tracking, one octave

Boss XS-1

Boss

44% similarity
$199.99via Reverb

Shared character: each note, tight tracking, one octave

EarthQuaker Devices Arpanoid V2

EarthQuaker Devices

42% similarity
$219via Reverb

Shared character: tight tracking

See all alternatives to the Electro-Harmonix Intelligent Harmony Machine (cheaper + boutique) →

Questions people ask

What are good alternatives to the Electro-Harmonix Intelligent Harmony Machine?+

The closest matches in character are the EarthQuaker Devices Rainbow Machine, the Meris MR Hedra, the Walrus Audio Luminary. Budget picks: Electro-Harmonix Pitch Fork Plus, Electro-Harmonix Slammi Plus, TC Electronic Quintessence Harmony Intelligent Harmonizer. Boutique upgrades: Alexander Pedals Fever Pitch, Meris Hedra Shifter, Mu-Tron Octave Divider.

What pairs well with the Electro-Harmonix Intelligent Harmony Machine?+

Strong matches from rig and tone-complementarity evidence: PRS MT100, Orange Rockerverb 50 MkIII 2-Channel 50W Head, Synergy SL2 Module — PRS MT100's own mid-forward character is the real reason this is worth trying.

How much does the Electro-Harmonix Intelligent Harmony Machine cost?+

Around $190.85 (live listing price, updated Oct 25, 2026).

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