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Sunday, May 27th, 2018 08:43 am

Synth Glossary

A Low Frequency Oscillator. It is similar to a normal oscillator except that it outputs very low frequencies (very slow waves) and is used as a control input into another part of the synth. Examples of its use are to create vibrato or tremolo effects....


The Xpander was Oberheim's first synth product that was designed from the ground up with MIDI in mind. It was a 6-voice, multitimbral analog synthesizer with an extremely flexible design. Each voice or group of voices could either be assigned to respond to a specific MIDI channel (1-16), to a specific keyboard range on a specific MIDI channel, or to any of 6 CV/Gate (1volt/octave) inputs. The output of each voice could be panned separately (7-positions) in the stereo output, or accessed individually through their own separate direct output. The Xpander also had a mono (summed stereo) output. Each voice consisted of 2 VCOs (triangle, saw, pulse, or noise, VCO2 could be synced to VCO1), a multimode VCF (low-pass, band-pass, notch-pass, high-pass and four "combination" filter modes), and 4 VCA's (in line one after each oscillator and two after the VCF). FM of VCO1 and the VCF was possible via VCO1. The filters could also be set as 1-pole (6dB/octave), 2-pole (12dB/octave), 3-pole (18dB/octave), or 4-pole (24dB/octave). All oscillators and filters could be tuned by a handy auto-tuned routine. In addition to this basic synth engine, the Xpander had a number of separate modules that could be inserted in any modulation path. These include (5) LFO's with basic waves plus sample-and-hold and random functions, 3 tracking generators, 3 ramp generators, a lag processor (does not necessarily have to be used for portamento), and 1 additional global LFO to be used with the Mod Wheel.

You could store 100 program patches and then set up an additional 100 multi-timbre setups storing any of those patches on each of the 6 voices, panning them and assigning how each voice is controlled. Patches could be dumped to cassette or via MIDI sys-exe.

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