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"It features real time additive synthesis with 240 oscillators, 16 voice polyphony, upwards of 240 oscillators and extensive programmability. The K150 implements a unique editing method in which you mix, combine and alter the 150's 22 resident voices and 69 preset programs. You basically manipulate sounds on a harmonic level for creating various new timbres. With extensive layering effects and abilities you can get some thick and unique sounds. There's 186 patches for memory storage and you can get up to 255 when you remove the installed sound blocks or overwrite presets.
The Fourier Synthesis (FS) is an upgrade (included in this device) to the standard K150 which allows you to define new instrument models by editing their velocities and envelopes, tuning intervals and more further expanding creative and unique sound synthesis potential.
Everything is modifiable and controllable about this synth. Pitch bending, vibrato, EQ, chorusing, polyphonic after-pressure and full 16 channel MIDI implementation with almost everything being MIDI controllable.
You can have up to 3 keyboard regions with up to 7 layers for each region for all sorts of splits/stacks/velo switches and so on. For every layer you can select one of the low-level instrument models and then globally assign controllers, set up the very flexible pitch LFO, add chorus/delay effects (not via DSP but by stacking up voices) and apply timbre shifts.
I find the parameters offered quite nice and very "musical": e.g. the response to attack velocity and the timbre is nicely adjustable - even via MIDI CCs if you like. Together with a fader box and maybe an arsenal of pedals, switches, joysticks and wheels you can do what the terminology implies: adjust an instrument to the musical context or playing style. It is really a fun to play expressively.
The sound hardware uses a 16 bit DA converter at about 20 kHz. The rolloff of the anti aliasing filter is rather smooth but the instrument models may compensate for this. Main CPU is a 10MHz 68000.
The user interface is - well - usable. The one line display and the OS have their limits but after a few days you get everywhere with a few button pushes. What leaves most other synths way behind is that all parameters are in real units: semitones, cents, dB and Hertz. This adds up to the general impression that someone was really trying to do it right.
Polyphony - 16 voices
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Oscillators - 240 osc! (sine and noise)
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LFO - Yes
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DCF - Yes
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DCA - 256 stage envelopes
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Keyboard - None (rackmount)
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Memory - 186 patches (up to 255)
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Control - MIDI (16 parts)
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Date Produced - 1986"