Intended primarily for electric guitar and bass, the Synth9 Synthesizer Machine from Electro-Harmonix is a polyphonic pedal designed to turn the sound of your instrument into a classic, vintage synthesizer—or more accurately, one of nine such synths, as the pedal offers nine different presets for achieving these tones. It’s suitable for effecting anything from buzzy synth-lead timbre, an atmospheric pad, or a synth bass.
Emulations of the Oberheim OB-X, the Prophet-5, various Moogs, and other classic synths are provided, and control over these synths is possible through the CTRL 1 and CTRL 2 knobs. In and of themselves, these dials have no endemic function, but once a preset is selected, they automatically control preset-specific parameters such as octave selection, sweep time of filters, vibrato, depth, and more. The DRY VOL knob will control the amount of unprocessed, untreated signal passing through the output jack, while the SYNTH VOL knob, with rare exceptions, controls the overall level of the emulated synth.
A single 1/4" input is provided, but to facilitate multiple routing methods, you’ll find two output jacks—one for dry signal, and the other for effect signal. It’s worth noting that this pedal works best when placed first in your signal chain, as distortion and modulation effects might muddy up the tracking algorithms, making precise note detection much harder to accomplish. It’s also recommended that you use this pedal with your guitar’s bridge pickup whenever possible, with the instrument's volume control cranked all the way.
A compressor has been built into the unit, and is constantly active on the synth emulations. The synths are capable tracking notes up to the 23rd fret of the high-E string and down to the low, open-A string of a bass guitar. Included with the pedal is an Electro-Harmonix 9.6DC-200BI power supply.
Controls at a Glance
SYNTH VOL knob: For all presets except MINI MOOD, this knob controls the overall volume of the selected preset at the Synth Output jack. In MINI MOOD, this dial controls the volume of the non-portamento synthesizer, while CTRL 1 adjusts the volume of the portamento synthesizer (Portamento is when the notes glide from one to another).
CTRL 1 & CTRL 2 knobs: The function of these knobs changes depending on the preset selected.
PRESET knob: This white, numbered knob selects the individual preset sound.
PROFIT V: The Sequential Circuits Prophet-5 provides inspiration for the PROFIT V preset. CTRL 1 adjusts the sweep time of a downward filter envelope. CTRL 2 selects between eight intervals of either octaves or 5ths.
VIBE SYNTH: A polyphonic synthesizer with decaying harmonic content and vibrato. CTRL 1 sets the power and sweep range of harmonics. CTRL 2 adjusts both vibrato rate and depth simultaneously. As you turn CTRL 2 clockwise the vibrato rate and amount increases.
MINI MOOD: A Moog-inspired synthesizer that blends a portamento synth with a non-portamento synth. Turn the SYNTH VOL knob to set the volume of the non-portamento synthesizer. Use CTRL 1 to adjust the output volume of the portamento notes. CTRL 2 sets portamento time. This preset works best when you play monophonically, one note at a time, where every note is picked. To play faster licks, try turning down CTRL 1.
EHX MINI: An emulation of the Electro-Harmonix Mini Synth. CTRL 1 sets filter envelope sweep time and direction. When CTRL 1 is set to a point within its counter-clockwise range, it sets the attack time for the filter sweep; when set clockwise beyond “noon” it controls the decay time of the filter sweep. CTRL 2 selects between four octaves.
SOLO SYNTH: A fuzz-synth preset where a synth oscillator and a fuzz square wave are combined. CTRL 1 is a tone control. CTRL 2 selects between four octaves.
MOOD BASS: The Mini Moog and Taurus pedals served as inspiration for this preset. MOOD BASS works best when played monophonically. CTRL 1 adjusts the sweep time of a downward filter sweep. CTRL 2 chooses between three octaves.
STRING SYNTH: This is an emulation of the ARP string synth. CTRL 1 is a tone control. CTRL 2 sets filter sweep attack time.
POLY VI: Inspired by the Korg PolySix, CTRL 1 is a tone control, while CTRL 2 sets modulation depth.