Digitech Mosaic

The DigiTech Mosaic is a polyphonic 12-string effect pedal from DigiTech, first available in December 2014¹. Instead of modulating your signal the way a chorus pedal does, it re-creates the sound of a 12-string guitar from an ordinary 6-string: octave-shifted low strings and doubled high strings, the same layout a real 12-string uses². DigiTech says it works with both 6-string electric guitars and amplified acoustics².

DigiTech describes the result as a lush, shimmering chordal effect, with what the maker calls "balanced low-end response with crisp octave shimmer" producing a tone that is lush and articulate². The pedal sits in a compact, pedalboard-friendly metal enclosure¹.

A 12-string sound from a 6-string guitar

A real 12-string guitar pairs each regular string with a second string: the lower courses are tuned an octave up, and the higher courses are doubled in unison. The Mosaic does the same thing electronically. DigiTech says the pedal delivers "immediately identifiable 12-string tones" with octave low strings and doubled high strings².

Because the effect is polyphonic, it tracks chords rather than single notes only, which is what a 12-string simulation needs: the jangle of a 12-string comes from all six courses sounding at once, slightly detuned and beating against each other. The Mosaic is aimed at players who want that sound without carrying a second instrument, and without the wider neck and heavier string tension a real 12-string demands².

Guitar.com's review placed the pedal in context: "As the Mosaic is basically an application of pitch-shifting technology"⁴. That is the key to how it differs from a chorus or detune pedal such as DigiTech's own Nautila: a chorus thickens the sound with delayed, modulated copies, while the Mosaic generates new pitched content, an octave below on the bass strings and a doubled unison on the trebles.

The controls: Level and Tone

The Mosaic keeps it simple, with two knobs.

MusicRadar described the effect as shaped by independent level and tone controls⁵. Guitar.com found the two knobs more capable than their count suggests: "There are only two controls, Level and Tone, but they're interactive, so there's a whole array of sounds and subtleties"⁴.

The same reviewer found humbuckers benefit from a brighter setting, so where you park the Tone knob depends on which pickups are feeding the pedal⁴.

Inside the pedal: 24-bit pitch shifting

The Mosaic is a digital pedal. It converts your signal with 24-bit A/D/A conversion at a 44.1 kHz sample rate, then applies its pitch-shifting processing to build the extra strings². Guitar.com characterized the whole pedal as an application of pitch-shifting technology⁴.

The published measurements point to a clean signal path:

• Frequency response: 20 Hz to 11 kHz with the effect enabled²
• Signal to noise ratio: better than -105 dB (A weighted), referenced to max level, 22 kHz bandwidth²
• THD: 0.004% at 1 kHz, referenced to 1 dBu with unity gain²

The pedal is true bypass, which DigiTech says preserves your tone when the pedal is not in use². It runs on a 9V DC power supply, which the maker notes makes it easy to integrate into an existing pedalboard²; Guitar.com's review listed a 9V adapter as supplied⁴. The enclosure is a compact, pedalboard-friendly metal box¹, made in China⁴.

Prices and availability

The Mosaic was announced at a suggested retail price of $187.44 MSRP³ and became available in December 2014¹. UK pricing was reported differently at different times: Guitar.com listed £109 RRP in its 2015 review⁴, while MusicRadar in 2020 reported UK availability at £129⁵. The two figures come from different dates and publications, so treat UK pricing as having shifted over the pedal's run.

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