Korg Wavestation EX

This is an article culled from archive material, circa 1997.

The first product to be produced by the ex-Sequential Circuits development team in Milpitas, California, the Wavestation keyboard was generally anticipated as the technological successor to the Sequential Prophet VS vector synthesiser. In fact, the Wavestation also drew heritage from Korg Japan's PCM sample-playback keyboards (specifically the M1), resulting in a ROM sample-based machine with weak onboard filtering. Nonetheless, it is a very powerful synthesiser: in addition to vector mixing (a 2-dimensional envelope controlling audio balance between four voices), it features wave sequencing, allowing a voice to play a loopable sequence of PCM samples, which may be rhythmic, cross-faded, or both. Wavesequences are either (globally) locked to MIDI beat clock or play back at an internal tempo of 100bpm. Oh, and this sample-based machine has hard oscillator sync.

Although wave sequencing has given the machine an enviable reputation amongst serious synthesists (as well as the blame for hoards of distinctive and recognisable sounds in commercials and films), one of the machine's greatest strengths lies with its dual effects processors, which are some of the best I've come across on a keyboard. The reverbs might be nothing to write home about, but the flangers, phasers, overdrives, enhancers and their ilk offer a wealth of programming possibilities and realtime control (especially via sys-ex), and are powerful tools when designing innovative, atmospheric sounds. The machine's architecture routes each voice individually to any combination of four effects busses (two for each processor), allowing vector mixing between effects. The processors may be arranged in parallel (each to a stereo output pair, with panning of two busses) or in series (with wet-dry panning across the final processor). They have identical algorithms.

The voice architecture is perhaps overly heirarchical: performances (which are the units of response to individual MIDI channels) refer to up to eight zoned and/or layered patches, each of which can contain four voices which may refer to the global wave sequence pool. Editing is very vertical, and irritates many editor/librarian packages.

The Wavestation's MIDI implementation is exemplary, with 16-channel multi-mode reception and robust and detailed sys-ex control over all parameters. However the lack of multiple edit buffers makes remote (computer) editing counter-intuitive, especially in multi-mode.

As a master keyboard the Wavestation is very respectable, offering multiple zones which sustain properly as new performances are selected. Like the Ensoniq VFX, the keyboard performance is distinct from any performances being driven via MIDI in multi-mode.

The original Wavestation keyboard was soon upgraded with a new (version 3) operating system, offering new effects parameters and algorithms, including some vocoders (a tempting combination with wave sequences), and later the Wavestation EX, with double the sample ROM. The rackmount wavestations (the AD and the SR) are both supersets of the EX, in terms of MIDI functionality; the voice architectures and sample sets are identical.

Aside: here's the spec. from Korg UK about the enhancements in the v3 firmware:

8 new effects have been added, including:
Mod Pitch Shift-Delay, a modulatable pitch shifter
Stereo Compressor-Limiter/Gate
Small Vocoder 1/2/3/4
Stereo Vocoder Delay 1/2
The Overdrive and Distortion effects now offer a modulatable output level.
The Performance Select Map may now be sent as a SysEx Dump.
The local keyboard may now be transposed.
Multiset channels now send and receive the MIDI Volume controller.
Key and Velocity Zones information may now be entered via MIDI.

Things to watch out for: Wavestation keyboards tend to degrade with time as the keyboard springs become misaligned: the usual symptom is sticky black keys. I believe the fix is easy, if fiddly. Some keyboards and A/D's exhibit software flakiness which (in the case of one of my A/D's) is often due to a bad PSU board; these are easily replaced. There is also a known problem with the front-panel decoding chip (possibly limited to the A/D), causing buttons to go offline; this problem was patched in the final OS release.

As a MIDI engine, the instrument is somewhat under-powered in terms of polyphony, with no voice prioritisation mechanism, which is a drawback. As a 16-channel sound module, having to share the two effects processors (especially with highly-specific effects) is a noticeable restriction.

I recently received details of the Wavestation's genetic keyboard disease from Paul Bundock at Korg UK:

This is caused by the lubricating grease on the
keys drying up or wearing off, it can also be
caused by bent key guides under keys. The cure is
to remove the base panel, remove both main circuit
board (KLM-1415 and o/p DAC board (KLM-1416) and
then remove the keyboard. The keys can be removed
from the key frame once the white plastic strip
that run along the back of the keys is
removed. Re-grease the key guides with perhaps a
silicon or lithium grease (you may be able to
obtain the original type of grease from your Korg
distributor). When replacing the key be VERY
CAREFUL not to bend the key contacts.
Alternatively, take your Wavestation to your Korg
dealer and have someone experienced carry out this
operation.