Image: Kimi95 at it.wikipedia, CC BY 3.0 — via Wikimedia Commons
ARP Quadra
| Category | Electronic (multi-section polyphonic synthesizer) |
|---|---|
| Country of origin | USA |
| Classification | synthesizer, synthesizer model |
| Wikipedia | en.wikipedia.org |
| Wikidata | Q3601143 |
Overview
The ARP Quadra is a multi-section polyphonic synthesizer released by ARP Instruments in 1978. Aimed at giving a single keyboardist a complete backing-section in one instrument, the Quadra combines four distinct sections: a polyphonic synthesizer, a polyphonic string machine, a monophonic bass voice, and a monophonic lead synthesizer. Each section has its own controls, and several can be played simultaneously across split or layered keyboard zones.
Origin & History
The Quadra extended the multi-section concept first explored in the ARP Omni, adding a more flexible polyphonic synth section and a dedicated programmable lead voice. The instrument also incorporated a phase-shifter effect built into its signal path. ARP positioned the Quadra as a flagship live instrument for keyboard players who needed pad, bass, and solo capability on a single board. The line had only a few years on the market before ARP’s collapse in 1981, and the Quadra became one of the company’s last major releases.
How It’s Played
The Quadra is played from a 61-key keyboard split or layered across its sections. Bass plays below a configurable split point; the strings, polysynth, and lead sections can be assigned to the upper zone individually or in combination. Each section has its own controls — string brightness and ensemble, polysynth filter and envelope, lead voice with monophonic priority — and the on-board phase shifter applies to selected outputs. The result is a more versatile single-board instrument than the earlier Omni.
Cultural Significance
The Quadra is closely associated with several visible players of its era, including Genesis’s Tony Banks and Jordan Rudess in his earlier career. Its specific sonic signature — particularly the strings combined with the lead voice — appears across late-1970s and early-1980s rock and prog recordings. As one of ARP’s final flagship instruments, the Quadra also marks the end of the company’s run of ambitious multi-section keyboards before its absorption.
Related Instruments
- ARP Omni – multi-section predecessor
- ARP 2600 – ARP’s semi-modular flagship
- ARP Pro Soloist – ARP’s preset monosynth
- ARP String Synthesizer – string-only ARP sibling
- Sequential Circuits Prophet-5 – contemporary polysynth standard
Frequently Asked Questions
How many sections does the Quadra have?
Four — bass, strings, polysynth, and lead.
Does it have on-board effects?
Yes — a built-in phase shifter.
Is the lead section programmable?
The lead voice has its own programmable controls, distinct from the polysynth section.