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Kurzweil K2700

Workstation Keyboard By Gordon Reid
Published March 2022

Kurzweil K2700

Now in its fourth decade, Kurzweil’s celebrated K series continues to evolve.

Released in 1991, the Kurzweil K2000 introduced the Variable Architecture Synthesis Technology (VAST) synth engine and it proved to be a great success. Then, when the K2000 was superseded by the K2500 and K2600, VAST was updated and further extended with things such as the KB3 organ and KDFX effects. However, it’s now been 14 years since Kurzweil killed off the K series, although they continued to develop VAST in instruments such as the PC3, PC4, Artis and Forte. There are numerous differences between these and the Ks, but the one that seems most to differentiate them is the omission of sampling. Sure, sample playback was reintroduced in the PC3Kx series, but many Kurzweil aficionados (myself included) have been looking forward to the day when the company releases a new K with all of the facilities of its ’90s predecessors brought up to date with everything that the 21st Century can offer. And here it is... or is it?

The Technology

In brief, the K2700 comprises the latest incarnation of VAST and its add‑ons, plus sample playback, effects and four flavours of sequencing. Available only with a hammer‑action 88‑note keybed, it weighs in at a solid 24kg, but it’s not as wide as one might expect because Kurzweil have sited its pitch‑bend and modulation wheels behind the keyboard rather than to the left of it. For some players this will be an irrelevance (I, for one, am not a big user of wheels) but others will disapprove more strongly. The keybed itself is responsive and doesn’t clatter, but it has a heavier action than I like on a synth; it’s fine for playing grand pianos, but I don’t view the K2700 as a stage piano with a bit of synthesis bolted on. You can, of course, adjust its velocity and aftertouch responses (the K2700 generates and receives channel aftertouch as well as receiving poly‑aftertouch) but a 76‑note semi‑weighted version would be welcome.

Unlike the rather spartan Forte, the K2700’s colourful panel is in many ways an extension of the PC4’s and, while I’ve heard criticism suggesting that it looks garish, I have to disagree; I find that the colours provide useful information when programming and performing. It has lost the LED ladders that on the Forte showed the current values of the nine control sliders, but the extra knobs sitting behind the nine faders, the transport controls (which work with external DAWs as well as the internal sequencer), the 16 programmable pads and the reinstated ribbon controller are all very welcome.

As delivered, many of the controls to the left of the screen perform standard functions that allow you to modify sounds without invoking the Edit menus, but you can direct their actions to multiple destinations simultaneously so that, in modern parlance, they act as macros, increasing a bit of this, decreasing a bit of that, while introducing a bit of the other. You can also assign a MIDI CC to each, which means that you can record and replay any adjustments that you make. If there’s a shortcoming here, it’s that the 480 x 272‑pixel colour screen is small by modern standards and lacks the touch‑sensitivity of its competitors. Nevertheless, navigation and editing isn’t a problem. Umm, no, that’s not entirely true; a larger screen would be of significant benefit. It’s been 17 years since I first bought a workstation with a large, full‑colour, touch‑sensitive screen, and it’s time that Kurzweil caught up.

As with all VAST synthesizers, it’s difficult to convey how different it is to program the K2700 when compared with PCM‑based instruments from other manufacturers. It’s not that it’s harder, it’s just that... oh well, let’s be honest, it IS harder because you have to learn different ways of doing things. This means that some users have shied away from programming their Kurzweils, which is a shame because there’s enormous potential here if you’re prepared to climb its steep learning curve.

In addition to using the PCMs contained within its 4.5GB factory library, the K2700 also allows you to load your own AIFF and WAV samples at 8‑bit or 16‑bit word lengths and with sample rates of up to 96kHz. Once imported, you can use these samples to build sounds by creating new Keymaps (the fundamental building blocks of VAST Programs) that contain them. To test this, I took a recording of my own voice, imported this as an aif, and then built a choir by creating and detuning multiple Keymaps and passing them though suitable effects. The results sounded great, but the time taken to achieve them was truly horrendous because of the lack of any graphics to aid sample editing. Previous Kurzweils have offered this, but the all‑important Trim page is missing from the K2700. Hopefully, the company is working on this because, if not, it’s a very nasty limitation.

The K2700 also offers Kurzweil’s KB3, FM and VA1 extensions. I wasn’t a huge fan of the KB3 organ when it first appeared, but it has improved over the years and I would now have no hesitation using it live or in the studio. If there’s a problem here... well, there are two. Most obviously, it’s uncomfortable to play screaming organ licks on a hammer‑action keyboard. Secondly, while the nine faders and their associated buttons are fine for use as drawbars as well as chorus/vibrato, percussion and key‑click controls, the rotary speaker’s speed is, by default, controlled by the Variation button that sits behind the master volume control. This is possibly the worst position if you’re playing with both hands and are hoping to flick from Chorale to Tremolo (or back again) in the split second between notes. Unfortunately, due to the absence of a left‑hand performance panel, there’s nothing that’s much better positioned. You can transfer this action to modulation sources such as foot pedals and aftertouch, but it would be nice to have a button or switch in a suitable position without having to screw one onto the front of the synth. (Don’t worry, Kurzweil... I didn’t.)

Next comes the 6‑op FM Engine, which offers many waveforms as operators. But if you want to stick with traditional sine‑wave FM, it’s trivial to recreate and load Yamaha DX/TX programs. When replayed, these sound exactly as one would expect but with 21st Century audio quality. The e‑pianos are gorgeous, and even something as simple as applying the K2700’s effects to a DX Pipe Organ is just... wow! An FM patch occupies a single Program Layer so it’s easy to recreate DX1 or even TX816 sounds, but each FM voice uses four K2700 voices so a four‑layer TX816 sound reduces its polyphony from 256 to just 16 notes!

Now we come to the K2700’s “power‑shaped oscillators along with DSP processing from Kurzweil’s mythical VA1 concept synth”. I have no idea what a power‑shaped oscillator might be but, in short, you can replace VAST’s sample‑based sound generation with your choice from 25 DSP‑generated waveforms, some offering both anti‑aliased (DSP hungry) and non‑anti‑aliased (less hungry) alternatives. Whichever you choose, these are then passed through the same VAST synthesis architecture as before but with additional modulation options, improved portamento, and some other minor changes. The manual claims that using these to program virtual analogue sounds is simple, but I disagree; getting my head around the so‑called KVA sounds was one of the most difficult aspects of learning VAST because their architecture bears so little similarity with the more basic VCO/VCF/VCA models of other manufacturers’ virtual analogue synths.

The K2700 offers three ways to create Multis based upon its Programs. The first two of these are dedicated Split and Layer modes that offer four parts (here called Zones), but these are just special cases of the third, which is the 16‑part Multi mode. As one would expect, this offers parameters to assign Programs to Zones with control over key ranges, velocity ranges and responses, pans, volumes, output destinations, transpositions, various weird key assignments, and an immense range of controller assignments and responses for each. You can also program Zones to send MIDI messages from the top‑panel knobs and sliders on a per‑channel basis, which makes the K2700 a powerful MIDI controller. This is also where you’re most likely to encounter three of the four types of sequencing in the K2700: MIDI CC (modulation) sequencers, Riff (pattern) generators, and arpeggiators (step sequencers). There are 16 of each type available and you can apply these on a one‑per‑Program or one‑per‑Zone basis. They’re most commonly used in the factory Multis to create auto‑accompaniments but, as always with VAST, there’s much more that you can do here.

You’ll find the fourth sequencer in Song Mode. This is a 16‑track MIDI sequencer that now has a massive capacity but combines useful features with some significant shortcomings. Most obviously, there’s no graphic editor. Editing a multitrack composition using an Event Edit page is very 1980s, and it’s not something to which I’m ever going to return. Even more seriously, there’s no Undo function. When I compare this to the fully equipped 16‑track audio plus 16‑track MIDI sequencers boasted by my OASYS and the Kronos, it’s clear that the K2700 isn’t intended to compete with these, and I doubt that I could ever use its sequencer as anything other than a MIDI file player or as a scratchpad. If you’re going to use a K2700 as a multitimbral sound source when composing or tracking, marry it to the DAW of your choice; your life will be a much happier one.

The K2700 measures 139 x 393 x 1295mm and weighs in at a considerable 24kg.The K2700 measures 139 x 393 x 1295mm and weighs in at a considerable 24kg.

The Sound

Kurzweil Programs often lack the ‘wow!’ factor of those on some other manufacturers’ synths, but this isn’t a criticism; sounds designed to capture your attention at a trade show are often useless when you try to find a home for them in a piece of music. In contrast, many of the factory Programs in the K2700 are immediately useful, and spending time with them is a good way to understand what it offers.

Let’s start with the acoustic piano category. Kurzweils have long been renowned for their piano sounds but, surprisingly, this is the area in which the K2700 is sometimes at its weakest. That’s not to say that the sounds are bad, but some of them exhibit unexpectedly uneven transitions between multisamples and velocity layers. If grand pianos are your principal motivation for buying an 88‑note Kurzweil, you might do better looking at the Forte.

The next two groups of sounds encompass Rhodes and Wurlitzer pianos, the CP‑80 and FM pianos, as well as other synthesized pianos, Clavinets and harpsichords. Many of these are excellent, and the only one that jarred was the RMI Electrapiano program, because it’s velocity‑sensitive (nooo!) and whoever programmed it treated the organ mode as an infinite sustain rather than as a long decay. Happily, these errors can be corrected and, having done so (and adding some gentle phasing to imitate the MXR Phase 100), the results were lovely. While there are some fantastic e‑piano emulators available from other manufacturers, there’s something very playable and likeable about the Kurzweil’s.

The next group includes the KB3 organs as well as a selection of Hammond and combo organs based upon sample‑based and FM synthesis. There’s also a selection of pipe organ ranks from which you can build your own chapel, church and cathedral organs. You can emulate stops using the buttons on the control panel and multiple manuals using keyboard splits, external MIDI keyboards and pedals. Of course, none of this is unique to the K2700, but the results can be first class.

The strings library in the K2700 is huge and, as well as its many ensemble sounds, it includes numerous solo violins, violas, cellos and contrabasses from which you can build your own ensembles. Some of these are drawn from the K series’ Orchestral Block, which makes them old enough to be worrying about the mortgage and getting the kids to school on time, but this also helps to ensure backward compatibility for fans of earlier Ks who are thinking of upgrading. Other Programs are derived from the PC3 and many more are new to the K2700. People have been using Kurzweil’s string sounds at the highest levels of music production for decades, and there’s nothing here to suggest that that’s going to stop. The same is true of the Brass/Wind category (which again draws upon existing libraries including Kore64) and of the dedicated Ensemble category. If none of these get your orchestral juices flowing, I don’t know what will.