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===EXi===
===EXi===
EXi is a Korg acronym for "EXpansion Instrument." It refers to all OASYS synth models other than the HD-1, including the AL-1, CX-3, etc.


====EXi Program====
====EXi Program====

Revision as of 01:27, 7 January 2008

OASYS
File:Korg oasys.jpg
Korg OASYS
ManufacturerKorg
Dates2005 -
Price$8000 - $8500
Technical specifications
Polyphony172 for HD-1, CX-3, & PolysixEX; 96 for AL-1;
48 for STR-1 & MS-20EX (all maximum;may vary
depending on other sounding voices and effects)
Timbrality16
Oscillatordepends on synthesis engine
Synthesis typePCM, Wave Sequencing, Vector, Physical Modelling,
Sampler, Analog Modelling
Filterdepends on synthesis engine
Aftertouch expressionyes
Velocity expressionyes
Storage memory1GB RAM, upgradable to 2GB. No physical ROM.
Preloaded samples include 314MB "ROM"
(loaded into RAM automatically at startup),
and optionally-loaded 313MB EXs1 "ROM Expansion"
& 503MB EXs2 "Concert Grand Piano."
0MB to 1.5GB available for user samples,
depending on memory configuration and loaded EXs.
Internal 40GB HDD.
Effects12 insert, 2 master, 2 total
Input/output
Keyboard76 or 88-key
Left-hand control2x Joystick, 2x Switch, Ribbon, Karma
External controlMIDI

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 is implemented on a custom Linux operating system and is designed to be arbitrarily expandable via software updates, with its functionality limited only by the PC-like hardware.

Features

The standard Oasys comes with a hardware similar to many personal computers:

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.

Synthesis engines

As of December, 20 2007 the latest version of the OASYS OS is 1.3.1, featuring the following synthesis engines:

  1. HD-1: A PCM synthesizer, with 628 MB of preloaded samples and Wave Sequencing
  2. AL-1: A 96-note polyphonic virtual analog synthesizer (84 notes in previous versions of the OS)
  3. CX-3: A modelled tonewheel organ based on the current CX-3
  4. STR-1: A plucked string physical model
  5. LAC-1: Optional bundle ($250) including two virtual analog synthesizers, the PolysixEX and MS-20EX, which are updated models of the vintage Korg Polysix and Korg MS20.
  6. MOD-7: Combines Variable Phase Modulation (VPM), waveshaping, ring modulation, PCM sample playback, and subtractive synthesis in a patchable, semi-modular synthesizer.


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 bandlimited 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 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:

  • The sample to play (mono or stereo)
  • Sample start offset
  • Reverse on/off
  • The length of the step, in milliseconds or rhythmic value
  • The crossfade time into the next step, in milliseconds
  • Crossfade fade-in shape (256 steps, from log to exp)
  • Crossfade fade-out shape (as above)
  • Volume
  • Transpose and fine-tune
  • Two modulation ("AMS") value outputs, to control any modulatable synthesis parameters in the rest of the Program (e.g. filter cutoff or resonance, LFO speeds, etc.)

And, for the sequence as a whole:

  • Time/Tempo mode (determines whether step durations will be in milliseconds or rhythmic values)
  • Run on/off (enables and disables programmed durations and crossfades altogether; modulation from other sources can control the sequence directly)
  • Key sync on/off (determines whether each note's Wave Sequence runs independently, or whether all notes sync together for lock-step rhythms)
  • Swing and swing resolution
  • Quantize Triggers on/off (adjusts note start times to match current KARMA/Sequence)
  • Start step and start step modulation
  • End step
  • Loop start, end, and direction (forwards, backwards/forwards, backwards)
  • Loop repeats
  • Note-on advance (increments the start step for each played note)
  • Position modulation (sweeps through the sequence manually)
  • Duration modulation (changes the step durations)
Differences from the Wavestation

Additions to the original Wavestation implementation include time/tempo modes, sample-locked tempo synch, constant-time crossfades in tempo mode, fade-in and fade-out shapes, swing, trigger quantization and key sync, note advance, realtime duration modulation, control of reverse and sample start point per step, and modulation outputs.

EXi

EXi is a Korg acronym for "EXpansion Instrument." It refers to all OASYS synth models other than the HD-1, including the AL-1, CX-3, etc.

EXi Program

This is the Program structure for playing EXi. It is similar to that of the HD-1, but differs slightly in a few ways, such as:

  • Allows selection of any two EXi for layering or splitting
  • Adds a "Common" step sequencer, shared by all voices in the Program
  • Adds audio input selection for each of the two EXi (currently used by MS-20EX and MOD-7)
  • Adds transposition for each EXi

AL-1

Virtual analog synth engine.

  • Two main oscillators with analog-style FM and sync
    • Korg claims proprietary anti-aliasing technology, for no audible aliasing over standard 88-note range, with sync (but with drive and ring-mod off)
    • Waveforms: Saw, Pulse, Saw/Pulse, Double Saw, Detuned Saw 1, Detuned Saw 2, Triangle, Square/Triangle
    • Wave Morph and Pulse Width/Phase/Detune
  • Sub-oscillator
  • Audio input
  • Noise generator with saturation and dedicated filter
  • Ring modulation (Ring Mod, AM, Rectify, Clip)
  • Mixer provides modulatable volume and filter a/b pan for osc 1, osc 2, sub osc/audio input, noise generator, and ring mod
  • Per-voice, modulatable Drive (nonlinear distortion) and Low Boost (low eq)
  • Dual resonant multimode filters, including "multifilter"
    • Multifilter provides two separate sets of gain controls for lp, hp, bp, and dry signals, with modulatable crossfade between the two sets
  • 4 EGs
  • 4 LFOs
  • 2 "AMS Mixers" (modulation signal processors)
  • Per-voice step sequencer

CX-3

Stub.

STR-1

Stub.

MS-20EX

Stub.

PolysixEX

Stub.

MOD-7

The MOD-7 includes six VPM oscillators, plus a PCM oscillator, noise generator, audio input, two multi-mode filters, three 2-in/1-out mixers, and a 6-input main mixer - with a patch panel for routing them together. The MOD-7 is capable of producing classic FM keyboards and bells to rhythmic soundscapes, synth basses, and sparkling, epic pads.

Notable Users

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