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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 Then, when the K2000 was superseded by the K2500 and K2600, VAST was updated and further extended with things such as the KB3 organ and KDFX effects.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.

By far the largest category, the Synth Programs encompass a huge range of monophonic and polyphonic sounds ranging from the most delicate tinkles to screaming outpourings of teenage angst. Many have names that tell you what inspired them and, despite fighting the impulse, I soon found myself playing the original tracks. This is also where you’ll find the VA1 sounds, many of which are, in my humble opinion, all but indistinguishable from those generated by genuine analogue synthesizers; it’s no accident that some of the biggest bands have for years been using Kurzweils on stage to replace their vintage synths. Complementing these, the Pad and Hybrid categories contain some gorgeous sounds that are, well, just gorgeous. You’ll find many of the K2700’s Mellotron patches here and... Oh no! There’s one named Trick Of The Tail. Somebody stop me please! Oops. Too late.

I’ve always had a soft spot for Kurzweil’s picked and chorused guitars, to the extent that in the early ’90s I even bought a K1000GX to extend the subset in my K1000PXA. Sure, there were more accurate guitar sounds to be had, but there was something very playable about the Kurzweils’ and there still is. Having said that, I don’t think that I would ever turn to a Kurzweil for lead guitars, but I rarely compose anything without using my K2500 for bass guitars; they have a depth and warmth that almost always works beautifully.

If you’re wondering where all of the vocal and choral patches are, you’ll find most of them in a category called Misc, which should have been named Vocals, Choirs, More Mellotrons, And All The Patches That We Couldn’t Decide Where To Stick Elsewhere. Again, there are numerous gems here. Finally, we come to the Drum/Percussion category. There are many useful sounds within the percussion Programs and, while I’ve never been a huge fan of Kurzweil’s drum kits, I suspect that other users will like them very much, and it’s unlikely that you’ll fail to find something here that works for you.

I view it as a mighty polysynth that would be a superb gigging instrument, both for its own sounds and for controlling other sources.

Final Thoughts (For Now)

It’s impossible to explain the complexities and possibilities of VAST in a review, so I’ve tried instead to give you some idea of how the K2700 sounds, what it’s like to use, and what its strengths and weaknesses might be. (If I’ve missed a feature that you feel is important... well, them’s the breaks.) But I suspect that what you most want to know is whether it’s a true successor to the K2500 and K2600. That’s much easier to answer: in my opinion, it’s not. Without sampling, the K2700 should more properly be named the PC5. But I can see why the company wanted to capitalise on the K series name; calling the K2700 the Forte 8 MkII or the PC5 wouldn’t have struck the same chord with fans of the brand, myself included.

The other thing that became clear during the review was that the K2700 isn’t designed to be a direct competitor to workstations such as the Korg Kronos or the latest Roland Fantoms that offer multiple synth engines, sampling, and much more powerful on‑board sequencing. Instead, I view it as a mighty polysynth that would be a superb gigging instrument, both for its own sounds and for controlling other sources. You may revel in its vast (pun intended) possibilities or you may be content to cherry‑pick from the factory library and perhaps tweak sounds to suit but, however you approach it, I’m pretty certain that you’ll be impressed. The K2700 can be as frustrating as it’s fascinating and as impenetrable as it’s playable but, as I have written before, there are times when a Kurzweil simply sounds nicer than the alternatives.  

Effects

The K2700 has an unusual effects structure. The basic unit is the Chain, which can contain up to 16 individual effects selected from numerous reverbs, choruses, delays, flangers, phasers, tremolos, panners, rotary speaker emulators, distortion units, EQs, compressors, filters, envelope followers, ring modulators, frequency shifters and more — up to a maximum of 32 units of DSP resources.

Each Program can take advantage of eight Insert Chains, with each allocated either to a specific Layer or to the Program as a whole, and there are two Auxiliary chains that can be used as additional Program chains or accessed by all of the channels in a Multi. You can also program up to 30 sources to control the parameters within the effects, and these can include VAST’s obscure mathematical functions as well as conventional modulators such as LFOs and contour generators. And if this isn’t complex enough, you can also modulate the modulators that are modulating the effects.

Of course, none of this tells you how the effects sound, but there’s nothing to worry about here — many of them are first‑class. But if I wanted to choose the most important aspect of the effects structure, it would be that it’s multitimbral, which means that you can (for example) apply a spring reverb, an overdrive and a rotary speaker effect to your organ, a nice ambience to your piano, overdrive, chorus and delay to your guitar... and more, up to the DSP limit. Then, at the end of the signal path, there’s a dedicated master effects section to add a final polish. The only obvious shortcoming is that, when sustaining notes of one sound while selecting a new one, their timbres and levels can change as the new Chains are initialised. There’s no glitch, but it’s something to take into account when planning sounds for live performance.

Backward Compatibility

When you consider that VAST was released more than 30 years ago, it’s amazing that the K2700 offers any degree of compatibility with its ancestors, but it will load many Objects (Programs, Multis, arpeggiator patterns, effects chains, Keymaps, and so on) from KRZ, K25, and K26 files as well as from the PCx, Artis and Forte series. Nevertheless, some of VAST’s previous algorithms can’t be loaded, Triple Mode Programs can’t be loaded, and neither can earlier KB3 Programs. Furthermore, the effects in the K2700 are different so, even if loading is successful, many Programs will require editing before they sound the same as before.

If you think that this sounds like a lot of caveats, I don’t blame you. But to put it into context, the Roland JD‑800 and Korg 01/WFD were launched in the same year as the Kurzweil K2000, and no‑one expects to be able to load their sounds into a Fantom or a Kronos. Consequently, I’m much happier about the legacy K2x00 sounds that I can still use than I am unhappy about those that I can’t.

The Rear Panel

The rear panel isn’t as busy as you might imagine for a flagship model such as this. For one thing, there are no digital audio outputs and it offers just four balanced/unbalanced quarter‑inch TRS analogue outputs arranged as two stereo pairs. (I must admit that I was surprised to find that you can’t direct sounds to these independently except by panning.) To the far right, there’s a quarter‑inch stereo headphone output that should, in my view, be sited on the front of the instrument. Alongside these you’ll find two XLR/quarter‑inch jack ‘combi’ audio inputs with mic/line/guitar level options and optional +48V phantom power.

Kurzweil K2700 rear panel connections.Kurzweil K2700 rear panel connections.

Four analogue controller inputs are provided: two for switches and two for continuous controllers. These are typically used for sustain and expression pedals, but you can reassign them on a per‑Program basis. The K2700 will analyse the polarity of connected pedals during power‑up so that you don’t obtain reversed operation, which is a nice touch. However, it has failed to reinstate the breath controller input that was lost after the PC3 series, which is not.

At the digital end of the panel, MIDI in and out (but no thru) are provided via 5‑pin DIN sockets as well as USB. Stereo audio is also available over USB with word lengths of either 16‑ or 24‑bit and sample rates ranging from 44.1kHz to 192kHz. Alongside these, a USB A socket supports low‑powered USB devices for external storage and updates. The final hole is an IEC socket for the universal internal power supply.

The K2700 Editor

Kurzweil K2700 editor.

The K2700 comes with a very basic Getting Started guide, and you have to download its manual from the company’s website. Having done so, this again illustrates the complexity of VAST synthesis. Happily, the first version of a free Soundtower editor appeared during the course of the review and, as always, it helped to clarify what’s going on in the depths of the synth. But it didn’t make everything clear and simple; there are too many parameters for that, resulting in numerous edit pages, at least one of which would require a computer monitor about four feet high to display all of its knobs and other options. I have to admit that I prefer the layouts of the editors for previous Kurzweils but, if you’re going to dig into the K2700, I would still recommend that you download and use this.

The Pads

The 16 velocity‑sensitive pads to the right of the panel can perform numerous functions. Most obviously, you can use them to play drum kits, chords of up to eight notes, and individual notes, which means that they can also trigger extended samples. You can program them on a per‑Program or per‑Multi basis to control all manner of parameters as well as to enable or mute individual arpeggiator or CC sequencer steps.

You can also determine whether just one pad can be used at any given moment or whether multiple pads can be used simultaneously, and select the MIDI channel on which they transmit, which means that you can use them to control external sound generators. Oh yes, and you can choose from a range of velocity responses to suit the sounds being played. It takes a while to create a new pad setup from scratch but, if you want to access the same pad settings for different sounds, you don’t need to reprogram them every time because you can import setups from existing Programs.

Which Kurzweil?

There are many similarities between the K2700 and the Forte. They share the same Fatar keybed, the same display, the same underlying synthesis engine, almost identical KB3, VA, FM and Kore64 extensions, the same number of arpeggiators, riff generators, CC sequencers, effects units and master effects, similar MIDI sequencing, and what appears to be the same degree of compatibility with previous K series models. Nevertheless, there are differences that might influence you to choose one over the other.

For pianists, the most important of these might be the fact that the grand pianos in the Forte are generated using a greater number of samples, which explains its much larger ROM — 16GB as opposed to 4.5GB in the K2700. So, if you’re after a stage piano that is also a powerful synth (rather than the other way around) you might be best advised to look first at the Forte 8. On the other hand, the maximum polyphony has been substantially increased in the K2700, the user sample memory has increased, and it offers substantially more factory Programs and Multis as well as more user memories. There are also advances in the USB implementation and, for the first time on a Kurzweil workstation, USB audio. You pays yer money and...

Pros

  • It’s an immensely complex and powerful synthesizer with a huge factory library of usable sounds.
  • What can I say about the Kurzweil sound? You either love it or... you love it.
  • It’s a powerful MIDI controller.
  • It’s both solid and attractive.
  • It has an internal, universal power supply.
  • Although it’s not a sampler, it can load and use samples generated elsewhere, but...

Cons

  • ... although it can load and use samples generated elsewhere, it’s not a sampler.
  • There are no graphics to aid sample editing, making this a tortuous process.
  • Its grand pianos are not the best that Kurzweil can offer.
  • A semi‑weighted 76‑note version with its pitch‑bend and modulation wheels in the right place would be welcome.
  • It would benefit from more, and individual, outputs.

Summary

Despite its name, the K2700 is an extended hybrid of the PC4 and the Forte. Furthermore, despite being described as a workstation, it’s not designed to compete with products that offer sampling and more powerful recording and sequencing capabilities. Instead, it’s a gorgeous polysynth with immense sound‑design possibilities. If you’re a fan of the Kurzweil sound, you have to check it out.

Information

£2499 including VAT.

www.soundtech.co.uk

www.kurzweil.com

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