Kawai K5 Synthesiser
Real-time additive synthesis at an affordable price will become a reality when the KS hits the shops later this year. Rick Davies previews Kawai's best yet.
IF THERE IS one thing that this year's NAMM and Frankfurt shows made unmistakably clear, it is that static waveform-based keyboards are on the way out. Samplers are more popular than ever. Yamaha's FM and Casio's PD-based synths continue to offer impressively wide selections of dynamic timbres. Roland's D50 uses short PCM samples to spice up digital waveforms. And Kawai's new K5 uses realtime additive synthesis - and does so for under £2000.
The K5 is a 16-voice instrument which features 48 "single", and 48 "multi" programs. In Single mode, the K5 plays one sound across the entire keyboard. In Multi mode, it assigns up to 16 "single" programs to individual key ranges which may overlap one another. When more than one sound is assigned to the same key, key velocity can switch from one sound to another, allowing the K5 to maintain its 16-note polyphony.
It's tempting to say that the K5 combines digital waveforms with conventional VCFs and VCAs, because that is almost the case. The fact of the matter, though, is that the Kawai's waveforms are generated using real-time additive synthesis, and all filtering takes place in the digital domain. So the K3 and K5 have much less in common than their appearances suggest.
Each "single" program consists of two "sources" which, by most synthesisers' standards, are complete voices on their own. Each source combines 64 harmonics to provide a raw (though by no means static) waveform, whose pitch may be modulated by any of four modulation sections. The resulting waveform is then processed by an 11-stage digital formant filter (DFF - good for vocal sounds), a digital dynamic filter (DDF), and a digital dynamic amplifier (DDA). In effect, the K5 provides control over its sounds at a similar level to most analogue synthesisers, though the terms and controls used differ considerably.
The real key to the K5 is its digital harmonics generator (DHG), which controls the dynamics of each source's set of 64 harmonics. A high-resolution LCD gives a graphic representation of the basic harmonic structure, and with its help, you can adjust the level either of each harmonic individually, or of groups of harmonics. A "trend" function allows groups of harmonics to be scaled either uniformly or with a tapering effect on higher harmonics for more natural-sounding timbres.
To add motion to the basic timbres, the level of each harmonic can be modulated by the four modulation sections mentioned above. Each of these combines the effects of key velocity, monophonic aftertouch, key number, LFO, and a six-stage envelope. This provides a selection of four complex dynamic modulation sources, which will certainly be easier to deal with than individual envelopes on each harmonic.
The K5 provides individual keyboard scalings and LFOs for each source. The overall pitch of each source is set by the digital frequency generator (DFG), which also provides a six-stage envelope for pitch modulation.
Although additive synthesis has come out of the shadows in the last year or so, the K5 is certainly the first affordable real-time additive synthesiser. When the level of a harmonic, or group of harmonics, is adjusted, the sound is instantly altered, whereas on other additive systems, harmonics must be updated following a pause while the computer calculates the new waveform.
The K5 also brings release velocity back to keyboard players. The DDA has a dedicated seven-stage envelope, and any of those stages may be modulated by attack (note-on) or release (note-off) velocity, so that the dynamics of each note can be altered by how quickly or slowly you release each key.
Until now we've been discussing only one source, though, and there are two sources in each "single" program. Although the two sources are most likely to be used in parallel, with two different timbres, they can also be used together as a single 128-harmonic source (just in case 64 harmonics aren't enough). Add the K5's "multi" programs to all of this, and the potential is there for a superbly flexible and musical keyboard instrument.
Programs may be stored in any of the internal "single" or "multi" program locations, or on RAM cards inserted into a front-panel slot.
To do justice to the K5's multi-timbral capability, four assignable audio outputs accompany the main summed output on the back panel, making this instrument well-suited to recording applications.
And the K5 is also available as a rack-mounting module, the K5M, in case you already have all the keyboards you need. Note, however, that not many keyboards generate release velocity, so not all controllers will take full advantage of the K5's DDA section if you opt for the module.
The K5's success will depend mainly on the range of sounds provided as factory programs, especially since many synthesists will require some reference points to get going quickly. On the other hand, this is the first time additive synthesis has been so accessible, so there is likely to be a lot of interest in this instrument one way or the other.
In the meantime, you can look forward to a full review of the K5 in a forthcoming issue. I know I am.
Prices K5 £1597; K5M, £1159; both prices provisional, including VAT
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Review by Rick Davies
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