Multitrak

Sequential Circuits Multitrak, photo courtesy of Matrixsynth

A polyphonic analog synth created by Sequential Circuits, and introduced in 1985. Sequential created the Multitrak during a period when rapid innovation was occurring in the synth industry, and Sequential was trying to create a successor to the Prophet 5, while at the same time trying to compete on cost and features with the Japanese manufacturers. In order to offer something unique, Sequential was moving in the direction of creating what we now refer to as arranger workstations, with extensive sequencing capabilities which most other manufacturers were not offering as an integrated capability at the time.

The Multitrak was a follow-on to the Six Trak, introduced the previous year, and it added to the Six Trak's capabilities. Like the Six Trak, it was six-voice polyphonic, and the voice architecture was the same: one VCO with triangle, sawtooth and pulse waveforms, a low pass VCF, a VCA, an LFO, and three ADSR envelope generators, one dedicated to the VCA and one to VCF cutoff frequency; the third routed to the VCO frequency (an addition to the Six Track architecture). Unlike the Six Trak, the Multitrak also had a built-in chorus, with knobs on the panel available to vary the rate and depth. The synth was multitimbral; the keyboard could be split and a different patch assigned to each half. An interesting aspect of the synth was how much control it gave the performer over voice allocation. The performer could choose how many voices to allocate to each half; for instance, if the performer was playing left-hand bass "comping", they might choose to allocate only one voice to the left hand for the bass part, leaving the other five voices to play chords with the right hand. Layering (referred to as "stacking" in the manual) was also available, and the performer could choose the number of voices to layer on a note, and assign a different patch to each layer. The synth could also be placed in MIDI mode 4, to be controlled by an external MIDI sequencer, and have a different patch assigned to each voice.

A considerable improvement over the Six Trak was the patch programming interface. Where the Six Trak used a basic one-knob interface, the Multitrak used a sort of switch matrix to select parameters to edit. A matrix of the available parameters was silkscreened onto the panel, of four rows by 10 columns. To select a parameter, the performer used a pair of row up/down buttons to select a row (indicated by LEDs), and then pressed a column button to select the parameter within that row. Changing the value was accomplished by turning a rotary encoder. Onboard patch memory held 100 patches, and patches could be transferred via either a cassette interface, or via MIDI. Performance controls were standard for Sequential's synths of the time: a 61-key keyboard with velocity (the Six Trak did not have velocity), a pitch wheel, and a mod wheel that controlled the amount of LFO going to all destinations to which the patch routed the LFO to.

The sequencing capability was essentially the same as the Six Trak; the main improvement was in increasing the available memory, to a total of 4000 steps shared by four sequences; see the Six Trak article for a detailed description of the sequencer. A latchable arpeggiator was also provided, and it included a "repeat notes in the order they were played" mode, one of the first arpeggiators with this feature.

Sequential marketed the Multitrak as the keystone of a "system" of hardware (a popular concept with synth manufacturers at the time), which also consisted of the Six Trak, the MAX, and the TOM drum machine. With the introduction of the Multitrak, Sequential also introduced a MIDI interface cartridge for the Commodore 64 personal computer, and a software package that interfaced to all four synths. Among other things, the software allowed sequences to be stored on the computer, and it used the computer's memory to extend the Multitrak's onboard sequencer memory to 20,000 steps. It also allowed patches to be moved back and forth between the synths. Patch editing and sequence editing capability was planned, but it is not clear how much of this was implemented before Sequential went out of business in 1987.

The Multitrack is noted for two main issues. One is that, due to lack of space in the operating system EPROM, the Multitrak omitted the code that maps all of the program parameters to MIDI continuous controller numbers, which means that unlike the Six Trak and the MAX, the Multitrak cannot use a MIDI knob box as a programmer. Some (not all) revisions of the Multitrak hardware allow for installing a larger-capacity EPROM with a hardware modification, which adds this code and other features, from third-party vendors. The other is that, with many Multitraks, the memory backup battery only lasts a few months, due to a circuit design error. A fairly simple modification is available to correct this; see this Matrixsynth article. If, upon power on, the patch number display counts from 1 to 6, the battery is dead.