Electro-Harmonix Octave Multiplexer



  • High Filter
    low-pass filter, filtering out the high tones?
  • Bass Filter
    high-pass filter, filtering out the low tones?
  • blend
    mixes the clean signal with the effected signal
  • Sub (only on reissues)
    gives the sub-octave more punch



The Octave Multiplexer is finally back, generating deep, phat bass tones one octave below the notes you play into it. Dividing the Octave Multiplexer from other octave devices are the two separate smoothing filters that enable you to tailor your sub-octave signal to the exact bass sound you desire. Run your vocals through the Octave Multiplexer and sound just like Ike Turner.

a 70's Electro-Harmonix brochure

Now Synthesize a not one octave below the one you're playing. The Octave Multiplexer literally allows you to convert any standard electric guitar into an electric bass - making possible lightning fast bass runs. An unbelievable extension for horns and trumpets. It explodes the tonal capabilities of these instruments into the range of the bass and baritone horns. Five filters allow the user to shape the harmonic content of the new note from fuzz bass to a pure deep organ bass. The Octave Multiplexer is fantastic on voice too; it makes any singer sound like Ike Turner. The Floor Unit contains all the basic controls of the pedal in a compact modular form.


myFXDB user reviews

1 review, average score of 7 / 10

2015-12-127/10  one of my first pedals, it had a great sound. this was before the pog came out with better tracking and algorithms. should have kept it! funky and synthy sounding.

Most recent forum threads


  • Dimensions
    5 1/2" x 6 3/4" x 2 1/4" x 1 5/16" (original)
  • Weight
    1 pound 10 ounces (original)


EH-5900 EH-5901 eh ehx electro-harmonics electroharmonics electroharmonix octave multiplexor

Where to find one?

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EH-5900 EH-5901 eh ehx electro-harmonics electroharmonics electroharmonix octave multiplexor fx pedal stompbox stomp box guitar effects pedal lowpass lopass lo-pass lp lpf low-pass filter filter eq/excite/filter hpf hipass hi-pass highpass hp high-pass filter pitch/octave octavers octave lower octave 1 octave lower 1 octave down octaver frequency
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