The Siel Orchestra is an analogue subtractive

synthesizer A synthesizer (also synthesiser or synth) is an electronic musical instrument that generates audio signals. Synthesizers typically create sounds by generating waveforms through methods including subtractive synthesis, additive synthesis a ...

, which was produced by Italian manufacturer

Siel Societa Industrie Elettroniche (SIEL) was an Italian company that made electronic organs and synthesizers in the 1980s. Timeline of major products * 1979 - Siel Orchestra, Orchestra (Divide down oscillator network for full poly. Brass/string/ ...

from 1979 to 1982. The original Orchestra was very limited but still a very characteristic instrument for its time. It produces its sounds from a divide-down

oscillator Oscillation is the repetitive or periodic variation, typically in time, of some measure about a central value (often a point of equilibrium) or between two or more different states. Familiar examples of oscillation include a swinging pendulum ...

network and therefore has 49-note (unlimited) polyphony. Although it contains 4 sections of presets (Brass, Strings, Reed and Piano), which each contain two sounds, the only parameters that can be edited are Vibrato (LFO), Brilliance (for the Brass, which also has a separate 'Brass Attack'), Attack and Decay. This ultimately means that the Orchestra cannot produce many different sounds; however because of its Italian origin and its distinctive routing, the Orchestra sound is not matched by any other similar synthesizers. The Orchestra was later bought by

ARP Instruments ARP Instruments, Inc. was a Lexington, Massachusetts manufacturer of electronic musical instruments, founded by Alan Robert Pearlman in 1969. It created a popular and commercially successful range of synthesizers throughout the 1970s before dec ...

to be slightly modified, relabeled and then sold as the ARP Quartet. This version replaced the Reed section with an Organ one; however, aside from that the synthesizer was almost identical. The Orchestra does not support

MIDI Musical Instrument Digital Interface (; MIDI) is an American-Japanese technical standard that describes a communication protocol, digital interface, and electrical connectors that connect a wide variety of electronic musical instruments, ...

or any other means of communicating with other electronic instruments; however, it does include a volume pedal socket which could be mistaken for a MIDI port.

Orchestra 2

Later, a more programmable version of the Orchestra was released. It still used 4 preset sections; however, it offered many improvements over the original version. A better filter for the brass section was included and more sounds were added to other sections. It also introduced a very simple LFO, a graphic equalizer, octave transposition and an 'animator section' which was effectively a flange effect. It also had a pitch bend function which was surprisingly never included with the first version Orchestra.{{Citation needed, date=March 2025 Synthesizers Analog synthesizers Polyphonic synthesizers