Exit Interview: Kawai K4/K4r

In early 2021 I picked up the synth you see above: the Kawai K4r, a vintage digital rackmounted synth. It wasn’t my first time with the synth – I’d actually owned the keyboard version in the ‘90s, it being the first synth I ever bought new. It coming back to my rig was a sort of an exercise in both nostalgia and hole-filling – I’d just gone DAWless and it seemed like it would be good to have a machine to do the occasional piano sound or choir pad. Now, four years and several albums later, I’ve sold it and thus it’s time to look back at my time with this weird digital wonder.

What is it?

The Kawai K4 and its rackmount sibling the K4r were early digital synthesizers that came out in 1989. The K4 series built on the K1 (a crude synth that built sounds by layering singler cycle waveforms and a few lo-fi instrument samples), adding a crude and crusty digital filter (with resonance, a rarity for the time) and a much larger selection of waveforms, many of them 16 bit (as opposed to the K1’s 8-bit samples). Depending on the presets used, they offered 16 or 8 voices of polyphony, and were multitimbral. They also included a sample based drum kit on channel 10.

The differences between the K4 and K4r (apart from the obvious lack of keyboard on the rack mount) are quite simple: The K4 has effects but only a single stereo output; the rack model has 8 individual outputs (for multitracking in the studio, of course!).  

What Did I Like?

I owned a Kawai K4 in 1992, and in large part learned synthesis on it. I sold it many years ago but always missed it a little bit – enough to keep an eye out in case a rack mount came available locally. When one did, I picked it up and was pleasantly surprised to see this synth has actually aged really well! Unlike most ROMplers of its era, it’s not limited to sounding (entirely) like its sample set. The large selection of single cycle and digitally generated waveforms, the distinctively gritty filters and the relatively robust synthesis engine and modulation routings make it able to cover a lot of genuinely good synth timbres while also supplying some delicious lo-fi rompler pads and weird, wheezing digital artifacts. 

As an ancient and discontinued synth, there are a lot of patches available for it, and they’re free! You can find them with a quick search. I did and found they supplied a deep well of sounds to choose from without having to delve too deeply into the menus. I won’t say they cover everything (modern sound design ideas are obviously absent except by rare accident, and the majority lean toward ‘90s pop/rock) but there’s plenty of tasty synth sounds, ambient/New Age pads, and distinctive oddball effects.

Speaking of effects, the built in effects are grimy, slushy, rudimentary and utterly outclassed by anything modern. That said, they can contribute immensely to the vibe of the synth, and should definitely be considered if you find yourself choosing between a keyboard and a rack version.

This synth is an absolute Swiss Army Knife in the studio – I’ve used sounds from it for just about every part of a song, including front and center as lead lines and primary bass sounds. It really shines in production, where you can always dial up a preset that (perhaps with a little tweaking) really fills in one or more of the gaps in your song and adds a subtle, lovely lo-fi shimmer to the whole affair. It’s literally all over two of my last three albums – there aren’t more than three or four songs in total between them that have no Kawai K4 in their sound set!

What Didn’t I Like?

This thing is just plain a pain in the ass to program. It was pretty decently accessible compared to the competition in 1992, but by today’s standard, forget it – just endless button presses and tiny menus. It’s a shame, too, because the underlying engine is actually pretty straightforward and elegant – up to four oscillators per voice (in pairs of two), into a filter section (four oscillator patches get two filters, in series or parallel) into an amp. Each section has its own envelope, and there’s a nice number of places to plug in modulation. But getting there thru the interface, while straightforward, is extremely fidgety and tedious.

And while I celebrated the incredible selection of vintage patches freely available online, it’s worth noting that working with the sysex files and transfers on a modern computer to load the patches may take a bit of finessing to work right. And forget making custom banks of your favorite patches – as a vintage synth that was never popular, there aren’t many (none I could find) patch managers that work on a modern computer, so you’re usually stuck with whatever is collected in any given bank. I’ve made it work, but it is annoying. 

It’s also a real shame the rack mount version lacks the effects. Individual outs might have been a reasonable tradeoff back in the day, but now it just means you need to clear enough table space for a full-sized 61-key keyboard if you want the definitive version in your studio.

Other Factors?

I honestly didn’t intend to sell it, but someone I was selling some other stuff to asked about it and after some consideration I decided to let it go (along with the relatively rare Kawai MM-16 MIDI controller/programmer, as a bundle) to the guy. My reasons were that I had recently picked up another ROMpler, the much better known Roland JV-880; that I had wrung a lot out of it over the past three years; and that, frankly, I needed the cash more than the synthesizer. Also, I missed the effects of the keyboard version.

A weird side note: this synth usually sounds somewhere between the low side of mediocre and pretty bad, actually when you solo the patchers/play it alone (especially the K4r, which lacks effects). Demos of it online are typically pretty underwhelming for this reason. That said, this thing always works in the mix. I don’t know what dark arts are at work here, but once it’s sat in with everything else it sounds fantastic, and adds a subtle dusty/dirty digital sheen to the proceedings that’s quite nice.

Conclusion

I bought the K4r for $200 in March of 2021, and picked up the MM-16 controller I got with it for $60 a year or so later (also bought a new power supply for the MM-16 at $15). I sold the pair for $350, so I made about $75 on the deal – not bad, considering the amount of use I got out of it!

I was in no way tired of the synth, nor did I feel that I had exhausted its possibilities or usefulness. I’d own one again, especially if I ever find myself in a situation where I can keep the keyboard version around so I have the effects. It recently made the infamous Bad Gear show (where it fared nicely, I might add) so it’s probably due for at least a temporary popularity and price boost. I’ve seen these for $100 a couple of times, and frequently for under $200, but even at $250 this would be a bargain as far as vintage synths go. If you’re looking for an interesting ROMpler/digital subtractive hybrid synth with a distinctive character and considerably less famous history (and baggage) than its contemporaries, the K4 is absolutely worth consideration.

If I could leave you with a final thought, it’s that this is maybe the ultimate sidekick synth. You don’t necessarily want to put it front and center very often, and it’s rarely, maybe never, going to carry the bulk of the timbral load of a track. But it’s utterly fantastic at filling in those awkward little gaps, and layering under your more impressive synths, and contributing weird ear candy. I think that “sidekick” energy is what kept it from being successful in its day – in that time, all-in-one workstations were all the rage, and apart from lacking a sequencer the K4 did seem to aspire to that (and was marketed to that end) and it just fell flat in that role. But no one expects a 30+ year old ROMpler to carry that kind of load, so perhaps this is finally its time to shine.