The K5 and K5m Additive Synthesizers

This page reviews the architecture and main features of the K5. The Kawai K5 (keyboard version) and K5m (module/rack version) were - besides the Kurzweil K150 Fourier Synthesizer - the first mass market additive synthesizers. While the K5 seems to have been quite a failure on the market (just like the K150), Kawai went back to the concept of an additive synth with the K5000 some years ago.

The official names for the gems discussed here are:
Kawai K5 Additive Synthesis Keyboard and
Kawai K5m Multidimensional Synthesizer Module (long live marketing!).

Kawai K5m

Hardware and user interface

The keyboard version has 61 keys (5 octaves) with attack and release velocity and monophonic aftertouch, there is a pitchbend and a modulation wheel. The module (K5m) is a 4 height units rack device which also can be used standalone like a console. All the other features are identical for both keyboard and module version.

There are mono 5 outputs: 4 polyhonic individual outs which can be assigned in Multi mode and are always active in Single mode and one Mix output. There is the MIDI in/out/thru trio, jacks for expression (#11) and foot pedal (#4) and jacks for sustain/hold switch (#64) and for a Link footswitch that can be programmed to step through configurable sequences of 8 programs.

The user interface consists of a data entry wheel, bank select and patch select buttons, cursor arrows and buttons for global functions. Also there is one master volume and a switch to protect all memory settings. The huge LCD display has graphics for some parameters but not for the envelopes. Unfortunately the display has a very limited viewing angle. Another drawback is that the cursor gets lost easily and the arrow buttons are not always intuitive to use.

The synthesis architecture

The K5/K5m is 16 voice polyphonic and 15 part multitimbral. There are 48 Single and 48 Multi patches in internal memory plus the same number storable on RAM card. Each Single patch contains 2 sections which are usually layered (Twin mode) for two oscillators with 63 harmonics but also may be stacked (Full mode) to get 126 harmonics. Global per Single are the portamento - which works very well - the main LFO and the DFT, a virtual 11 band EQ, all other parameters are controllable per section.

K5 synthesis architecture

Modulation: pitchbend, #7 and #11 control volume (multiplicative), #5 for portamento time, #64 for sustain/hold, #1 and #4 are each assignable to vibrato, tremolo, harmonics mod, filter cutoff or filter slope, aftertouch has many predefined routings, velocity and release velocity can also control envelope rates. Overall impression: the routing is somewhat limited but all the basics are there. Especially the harmonics modulation is nice and can be used for cute spectral morphing effects.

Envelopes: Per section there are a pitch envelope, 4 harmonics envelopes, a filter envelope and an amp envelope. Each of these has 4 levels/rates plus 2 levels/rates for release, unfortunately only the pitch envelope can be looped. The amp envelope has one additional release rate and for each of its rate parameters and you can individually switch velocity control on/off.

Harmonics: The harmonics editor features a graphic display and some nice editing macros: you can e.g. edit only the even harmonics between 44 and 60 with relative emphasis on the lower ones. For dynamical sounds each harmonic is assigned to either one of the 4 modulation pathes or to no madulation at all (which gives full level). Each modulation path has its own harmonics envelope (see above) plus a LFO with only frequency control.

Filter/EQ: Has controls for cutoff frequency, slope and flat level which means it is can be shaped from a lowpass to something like a bandpass. The sound is strange and very different from what you would expect. The 11 band graphic EQ (called DFT) is nice but works with strange frequencies (from ~ 25 Hz to ~ 5 kHz). Since the K5 does have very little bass this doesn't really make sense.

Multi mode: The Multi mode implementation is very nice: for up to 15 parts you can define the Single patch, the MIDI channel, polyphony (dynamical or number of voices) transposition/tuning note and velocity ranges and lots of controller filters.

Sound

First: the K5 is noisy, has a relatively low output level, very little bass (some people told me they disagree on this point) and not much treble (maybe up to 10 kHz or so). The individual outs and the Multi mode are a little less noisy though and you can try a hardware modification.

If you use the K5 with other noise makers you will generally use the Multi mode for a richer stereo sound. What the K5 is good at are bright digital sounds: think of bells&chimes;, metallic whisper, synth choirs and brittle digital textures. To me the machine sounds like a typical early digital synth with lots of aliasing, harsh quantization and the like.

However it layers very nicely with soft analog-style pads and leads and may cut through your mix if you use it where it shines. It is also so thin sounding, even the 16 voice chorus of my SE-70 changes little of its character.

In short: I absolutely love the sound.


Support


K5 Hack page, KULT5000, The Kawai K3 page, Kurzweil K150 Fourier Synthesizer, SY-Links, SY-List archive, Music Machines, electronica, Analogue Heaven
Find out about commercial K5 PC Software (or mail to baw@efn.org).
Thanks to Andrea Toni for lots of infos and to Andrew (synth.site) for the picture. Any feedback is highly appreciated, mail to heja@neuroinformatik.ruhr-uni-bochum.de.

Back to the main page of the Institute