Korg Wavestation

Wave sequencing concept:
Four-step wave sequence with crossfades.

A wave sequence is a programmed list of PCM waves playing in succession.[9] Each step in the wave sequence can have a different duration, pitch, fine tuning, level and crossfade amount. Additionally, wave sequences can be looped (forward or forward/backward directions) to play indefinitely or for a finite duration; they may also be synchronized to the Wavestation's internal clock (at a user-adjustable tempo) or to MIDI clock signals from a sequencer. The result is a continuously changing sound, producing either a smooth blend of crossfaded waves, or semi-arpeggiated and rhythmic sequences, or a combination of both. In a Patch, different wave sequences can be assigned to each of the four oscillators, thus the Wavestation is capable of generating four distinct wave sequences playing simultaneously during a single note.[1] In Performance mode, up to thirty-two discrete wave sequences can be played at the same time by layering eight 4-voice patches, although the actual number of playable wave sequences may be less because an additional oscillator is required to execute a crossfade.[10]

Vector synthesis concept: Controlling the mix of four sound waves by defining a point on a vector plane using a joystick.

Simply, vector synthesis is dynamic timbre control over 2 or more voices (oscillators). On the Wavestation, vector synthesis can be applied on any two or four-oscillator patch.[11] The volume blend (or mix ratio) between oscillators is varied over time via a dedicated mix envelope, in real-time via the front panel's vector joystick, or via other controllers such as LFOs, aftertouch, and MIDI.

The mix envelope for a two-oscillator patch structure is arranged on a horizontal line or axis, and is interpreted as one-dimensional vector synthesis. Two dimensional vector synthesis requires a four-oscillator structure, with oscillators A & C arranged on the horizontal X axis and oscillators B & D on the vertical Y axis. A patch's mix envelope can be looped for a finite or indefinite amount of time as well as modulated by controllers. Moving the joystick whilst playing overrides the pre-programmed mix envelope, giving the user dynamic control over the timbre of the sound.

Similar in structure to the Ensoniq VFX and Korg's M1, the Wavestation's top level of sound control is the Performance, which organizes up to eight Patches (parts) and two independent effect processors.[12] A Performance also controls keyboard zoning, MIDI channel assignment, velocity switching, and other parameters. Each Bank contains 50 Performances.

Producing the synthesizer voices are Patches, the middle tier in the programming hierarchy. A patch consists of 1, 2, or 4 digital oscillators (A, B, C, and D). Tone generation is achieved by assigning any of the 20-bit PCM samples and single-cycle waveforms or a wave sequence to an oscillator. Each oscillator has its own digital filter, amplifier, amp envelope, general purpose envelope, two LFOs, and numerous modulation routings.[13] The mix envelope for vector synthesis is also found at the Patch level. There are 35 Patches per Bank.

Wave Sequences are at the bottom tier of the Wavestation's programming structure. The Wavestation treats these as if they are discrete PCM waveforms when assigning them to oscillators in a Patch, although a wave sequence itself is created from a list of PCM waveforms in ROM or Card memory. The maximum number of steps per wave sequence is 255, and the maximum number of steps allocated per Bank is 500.[9] It is therefore possible to exhaust the step memory in a Bank with two very long wave sequences. 32 wave sequences are available per Bank.

The Wavestation's Multimode organizes up to 16 Performances (one per MIDI channel) and two effects into a Multiset, which allows for multi-timbral reception from a MIDI sequencer or master keyboard controller.[14] Multisets have two major drawbacks.[3][15] First, a single, complex Performance may use up all of the polyphony in the Wavestation with only one or two keys depressed, so multiple complex Performances would result in extreme voice-stealing. The other drawback is that effects are vital to the overall sound of the Wavestation, but a Multiset cannot have 32 effects. So it ignores the original effects in Performances and assigns two new effects for use with all 16 Performances. Since a Performance can also transmit and receive multi-timbrally on eight parts, Multisets are generally superfluous.[16]

• Wavestation (1990) – The first Wavestation keyboard to reach the market, it premiered the vector synthesis and wave sequencing concepts under the Korg brand. Its 2MB soundset was synth-oriented which lacked acoustic piano sounds and drums, relying instead on sampled waveforms from classic synthesizers of the 80s, most of the Prophet VS waveforms, and numerous attack transients and instrument samples from Korg's sample library.[21] It could take Korg's proprietary PCM and RAM type expansion cards. The user interface comprised a 64×240 backlit, graphical LCD display with soft-key menu system (the buttons under the display), a data entry dial similar to that used on Roland's Alpha-Juno keyboards, a numeric keypad and other function buttons. A 61-key semi-weighted keyboard, pitch and modulation wheels, and a vector joystick comprised the player controls. The Wavestation received much critical acclaim, including Keyboard Magazine's "Hardware Innovation of the Year."[4]
• Wavestation EX (1991) – Identical in form to the original Wavestation keyboard, Korg created the EX in response to player feedback and criticism. The EX doubled the ROM to 4MB by adding 119 new samples (most notably piano, drums, and the remaining Prophet VS waves), and eight new digital effects. Bugs in the operating system were also fixed (though several still remained). Those who had purchased an original Wavestation could buy the EXK-WS upgrade kit to convert their keyboards to the EX version. The iconic Macintosh start-up sound was generated on a Wavestation EX by Apple sound designer Jim Reekes.[22]
• 

  Wavestation A/D
  Wavestation A/D (1991) – It was the first rackmount version of the Wavestation technology. Korg replaced the large joystick with a smaller version, the same display from the keyboard versions was retained, and an additional RAM bank added. A unique feature was its analog inputs, capable of accepting guitar, mic and line-level signal; it allowed the effect processors to process those signals in realtime (particularly useful with the vocoders in the new EX effects). All of the keyboard's front panel buttons also survived the transition, making the programming process identical to the original Wavestation. The A/D inputs also were an option when creating wave sequences, incorporating the input signal into the synthesis engine in realtime.
• 

  Wavestation SR
  Wavestation SR (1992) – The last hardware implementation of the Wavestation was a 1-unit rackmount model. It lacked the A/D inputs of its predecessor, the screen was downsized to a character-based 16×2 LCD, and most buttons, function keys, and the joystick disappeared. Marketed as a preset module, it featured eight ROM preset banks with Patches and Performances previously sold on expansion cards from Korg and Sound Source Unlimited, Inc. Without an external MIDI sound editor, programming was a very difficult task due to the small display, although all parameters can be edited from the panel.
• 

  KLC Wavestation
  Software Wavestation (2004) – Fourteen years after the first Wavestation appeared, Korg released a software-based emulation of the synthesizer which also included all the instrument patches from Korg's line of expansion ROM cards. In late 2006 Korg released version 1.6 of the software Wavestation which added a resonant filter. Also, "50 new Performances, 35 new Patches, and 32 new Wave Sequences are added to take advantage of this new resonant filter."[23]
• iWavestation (2016) – This is a native program for the iOS platform (iPhone and iPad) which recreates the physical synthesizer. It can be downloaded from Apple's AppStore. It includes all the instrument patches from Korg's expansion ROM cards as in-app purchases. Current version (as of May 2021) is 1.1.1.