The Korg OASYS is a workstation synthesizer released in early 2005, 1 year after the successful Korg Triton Extreme. Unlike the Triton series, the OASYS uses a custom Linux operating system that was designed to be arbitrarily expandable via software updates, with its functionality limited only by the PC-like hardware.
OASYS was a software implementation of the research project that ultimately resulted in the OASYS PCI, a DSP card which offered multiple synthesis engines. The original OASYS keyboard concept had to be scrapped because of excessive production costs and limitations of then-current technology.
Production of the OASYS was officially discontinued in April 2009. Korg sold just over 3000 units worldwide. The final software update was released on November 24, 2009.
In 2011, Korg Kronos, a successor of Korg OASYS, was introduced at that year's NAMM Show.
Features
The standard Oasys comes with hardware similar to many personal computers: 2.8 GHz Pentium 4 CPU 40GB hard disk drive 1GB DDR RAM, user-expandable to 2GB 10.4" LCD touch screen
It features Korg's OASYS (acronym for Open Architecture SYnthesis Studio) technology, which allows multiple synthesis engines to be used simultaneously. The OASYS also includes second-generation KARMA technology (with the first generation having first appeared in the Korg KARMA). It has either a 76 key synth-action, or 88 key hammer-action keyboard.
Options
EXB-DI (Digital interface board)
The optional EXB-DI adds 8 channels of ADAT Optical format 24-bit 48 kHz digital output, as well as a word clock input. The EXB-DI was first made available for the Korg Triton Studio keyboard and Triton Rack module - on these units only 6 outputs are available via ADAT. Bar a few early models of the Oasys, the EXB-DI is user installable.
Synthesis engines
As of November 24, 2009 the latest version of the OASYS OS is 1.3.3a, featuring the following synthesis engines:
HD-1: A PCM synthesizer, with 628 MB of preloaded samples and Wave Sequencing. EXs: A sample library that works by itself or with other engines. EXs-1 is a set of instruments and EXs-2 is a grand piano. AL-1: A 96-note polyphonic virtual analog synthesizer (84 notes in previous versions of the OS) CX-3: A modeled tonewheel organ based on the current CX-3 STR-1: A plucked string physical model LAC-1: Optional bundle (originally $249.00, but now available for free) including two virtual analog synthesizers, the PolysixEX and MS-20EX, which are updated models of the vintage Korg Polysix and Korg MS20. The LAC-1 is available as a free upgrade, but has to be requested by the current owner of the OASYS from Korg. MOD-7: Optional (originally $249.00, but now available for free) that Combines Variable Phase Modulation (VPM), waveshaping, ring modulation, PCM sample playback, and subtractive synthesis in a patchable, semi-modular synthesizer. The MOD-7 is available as a free upgrade, but has to be requested by the current owner of the OASYS from Korg.
HD-1
HD-1 Program
The HD-1 is a sample+synthesis engine with a two "oscillator" structure. In addition to the two "oscillators," an HD-1 Program contains a Vector Envelope, Common LFO (per-program as opposed to per-voice, similar to the modulation LFOs in some early polyphonic analog synths), two common key tracking generators, KARMA settings, and effects.
HD-1 Oscillator
Each "oscillator" consists of a sample playback oscillator, dual multimode filter, nonlinear "drive" and low boost section, amp, and pan. The sample playback oscillator has four velocity zones, each of which can play a mono or stereo sample or a Wave Sequence. Velocity zones can overlap or crossfade. Korg claims very low aliasing distortion, due to the use of band limited interpolation.
Wave Sequencing
Wave Sequences were first introduced on Korg's Wavestation synthesizer, released in 1990. Wave Sequences allow a single note to play through a list of samples, one after the other, with or without crossfades, with other associated parameters changing for each sample, as listed below. This can create smooth, evolving timbres, or rhythmic effects. Internally, Wave Sequences are implemented by using two voices; voice A plays the first sample, voice B plays the second sample, voice A plays the third sample, and so on. Other synthesizers have featured concepts which are similar in some aspects, such as PPG, Waldorf, and Access Virus wavetables, Synclavier resynthesis, and Ensoniq Transwaves and Hyperwaves (see the Ensoniq TS 10).
In the lists below, features new to the OASYS (in comparison to the Wavestation) are noted.
OASYS Wave Sequences include, for each step: