The Split-8 is a polyphonic analogue keyboard synthesizer manufactured by Sequential Circuits. Built in Japan and going by the alternative name Pro-8 in some markets, this was one of the last synthesizers produced by the company and was assigned model number 608. It was released in 1985 at a list price of $1,199 (or $1,195; this number varied between advertisements). This and some other Sequential Circuits synthesizers (the Six-Trak, Multi-Trak and MAX) were built around the Curtis Electronics CEM 3394 "synth-on-a-chip" integrated circuit, and used a Z80 as their central microprocessor. Features and Cabinet Brief Summary of Features This electronic keyboard is an 8-voice polyphonic, bi-timbral analogue synthesizer with the ability to split or layer two sounds ("double" mode). It has 64 memory locations for sounds ("patches"). Patches may be "linked" in memory so that calling up one automatically calls up the second for a split or layer. A monophonic mode, with all eight oscillators producing the same sound at once, is also possible. Polyphonic portamento is also available. The instrument features MIDI, including the capability to save and restore patches with system-exclusive data (see MIDI for more detail about this process). Front Panel The front panel has two volume knobs (one for each available sound), a master tuning knob, a data entry knob for programming patches, modulation and pitch wheels, various buttons for mode (layer, or "double", split) and program selection, and a four by eight grid for programming (with all parameters labelled on the grid; see Figure 1). Some other functions are also listed on the panel as a reminder of which buttons to press. The case is metal with light blue graphics and lettering, red LED indicators, and black painted wooden end pieces. Back Panel The back panel has quarter-inch jacks for recording data to cassette tape (one also doubling as a footswitch input), MIDI in and out DIN connectors, separate quarter-inch audio outputs for each of the two sounds and a mix audio out (both sounds combined), a power switch, and a fuse socket. Keyboard The keyboard is five octaves (61 notes, C to C) and is unweighted. It has no velocity or aftertouch sensitivity. Voice Architecture and Sound Programming Voice Architecture The synthesizer voices are based on the Curtis Electronics CEM 3394 chip. This allows for one voltage-controlled oscillator (VCO) per voice, with on/off toggles for any combination of sawtooth, triangle and variable pulse waveforms.