Hands-On Review:Kurzweil K2600 and K2661- The Evolution of a Revolution

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By Michael K. Dennison


The revolution

In the brief history of modern keyboards, there have been a few outstanding synths that have knocked musicians on their collective kiesters with radical new sounds and technologies. Almost without exception, these groundbreakers left their sonic imprints on a musical era and then were quietly consigned to the "vintage gear" market or the "what-ever-happened-to..." discussion groups.


But one stalwart line has weathered both time and musical fashion, from its not-so-humble debut almost 20 years ago to today's gloriously rich descendants: the Kurzweil K series. Starting with the K250 in 1984, Kurzweil brought unprecedented power to the working musician. Famed for its beautiful grand piano samples, as well as classic patches such as "Cathedral Choir," "Soft Tenor Sax," and "Slo Solo Cello," the K250 found its way into keyboard rigs, recording studios, and composer's lofts around the world in very short order.


Evolution followed revolution and the K250 was followed by the K1000, K2000, K2500, and most recently, the K2600. I began my own relationship with the Kurzweil family in '96 when I purchased the K2500. With 76 semi-weighted keys, a plethora of hands-on controllers, the endless possibilities offered by Kurzweil's V.A.S.T. operating system, and of course, fantastic sounds, I was in synth heaven! I spent countless hours exploring and creating with a musical palette I had never enjoyed before. Not only was the realism breathtaking, the ability to take that reality and twist it into dream or nightmare soundscapes was incredibly energizing.  In one of their frequent software revisions, Kurzweil added what they call the KB3 mode. For B3 aficionados, KB3 mode offers astoundingly accurate tonewheel emulation - it even gives you adjustable tonewheel leakage! The eight front-panel slide controllers plus the mod wheel function just like B3 drawbars, adding more of each slider's partial as it's pulled down/towards you. The buttons above the sliders toggle Leslie spin, vibrato, key click, and percussion settings.


State of the art
In 2001, Kurzweil unveiled the powerful successor to the throne-the K2600.  Decked out in its princely purple raiment, the K2600 cut quite a figure. Things were a bit bolder under the hood, too. Previously available only as an option, Kurzweil's KDFX effects processing engine was now standard fare (though the quality of KDFX is anything but standard). The K2600 further upped the ante with a refined keyboard action, quieter electronics, balanced I/O, improved sampling options, and the ability to add as many as four ROM expansion boards.


The K2600 also added a few completely new features to the mix that help it keep its place at the head of the food chain. A first-rate 24-band vocoder takes advantage of the K2600's sampling option and powerful filters, and offers hands-on control of envelope follower speed, bandpass filter width, and frequency offset of the carrier bands. It's a little extra on the K2600 that holds its own against many purpose-built vocoders on the market!


Triple Modular Processing, or Triple Mode, made its debut in the K2600 as well. While the description is disarmingly simple, Triple Mode offers perhaps the deepest set of programming possibilities ever on any synth, at any price! In essence, each program can have up to three layers, linked to provide one single voice. This might not be so mind-boggling if it weren't for the fact that each triple layer features its own algorithms: 30 for layer 1, 38 for layer 2, and 26 for layer 3, for a combined total of nearly 30,000 possible combinations! Factor in the 3 to 18 DSP functions available for each stage of each individual algorithm, and you're now looking at possibilities ranging into the trillions! While this may seem overwhelming, with a little practice you'll find that it's very easy to come up with fresh, musically useful sounds.


As a work-in-progress, the K2600 is constantly being upgraded. The latest OS is quicker and more responsive than ever and is always available online at Kurzweil's site. They've also retired the purple version, with the latest models dressed in black and stylish titanium accents.


The continuing evolution

The latest branch on the Kurzweil family tree is the K2661.  Smaller, lighter, and quicker than its predecessors, it is, nonetheless, a full-fledged member of the K-series family. Its 61-key custom-designed un-weighted Fatar keybed provides fast synth-style playability with solid, smooth action. It features all the famed Kurzweil sounds, including their acclaimed Stereo Grand Piano, as well as Contemporary, Orchestral, and General MIDI sound sets. In addition to the 32MB of sound ROMs included, there is space for two additional ROM boards. (Would you like a set of Vintage Keys with that order?) A host of new voicings - their freshest and most exciting yet - promise to make this 'board a star of studio, stage, and screen in short order.


Like the older generation, the K2661 features SCSI connectivity, mono aftertouch, pitch and mod wheels, plus eight programmable sliders and buttons, making it a powerful MIDI controller in its own right. It has my old K2500 beat in the output department, with six balanced outputs plus optical digital ports that be configured for S/PDIF or ADAT lightpipe, for up to eight channels of 24-bit digital I/O!


I have to admit
It's getting better all the time! For a few short days, my studio enjoyed the sounds generated by these latest additions to the Kurzweil line, and it's sparked a renewed programming frenzy with my trusty K2500. Without a doubt, this is gear for the ages - anybody serious about synthesis and sampling owes it to their art to check these 'boards out today!


Shared Features & Specs:

  • 48-note polyphony with 192 oscillators
  • Fluorescent 64 x 240 backlit LCD display
  • KB-3 Organ Mode provides powerful tone wheel organ synth models
  • Stereo Grand Piano
  • V.A.S.T. Variable Architecture Synthesis Technology with 60 DSP functions
  • Full MIDI controller capabilities including sliders, footswitches, pedals, and breath controllers
  • New Triple Modular Processing
  • Extensive sample-processing capabilities
  • 32-track sequencer with full editing
  • 16 MIDI channels
  • Powerful KDFX 5 stereo bus with 24-bit digital effects
  • Sampling option with analog and digital I/O and sample-while-play capability
  • Live Mode - real-time processing of live inputs
  • Over 450 programs provided
  • Balanced analog audio outputs
  • Stereo headphone output
  • Flash memory for OS and ROM storage
K2600 Keyboard
Kurzweil K2661
61-Key Sampling Workstation
  • 76-note semi-weighted and 88-note fully weighted keyboard versions available
  • 64MB sample memory upgradable to 128MB
  • Up to 44MB onboard ROM sounds
  • 2 ribbon controllers
  • DMTi Digital Multitrack interface option for data format and sample rate conversion, and multichannel digital patchbay
  • 61-note unweighted synth-style action
  • Optional ribbon controller
  • Up to 48MB onboard ROM sounds
  • Optical digital ports are selectable as ADAT Lightpipe or S/PDIF for up to 8 channels of 24-bit digital