Kurzweil K250

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The Kurzweil K250 a.k.a. "Kurzweil 250", "K250" or "K-250", manufactured by Kurzweil Music Systems was the first combined live performance and studio electronic musical instrument which produced sound derived from sampled sounds (see:Sampler (musical instrument)) burned onto integrated circuits. Acoustic sounds from brass, percussion, string and woodwind instruments as well as sounds created using waveforms from oscillators were utilized. Primarily designed for the professional musician, it was conceived and invented by Raymond Kurzweil, original founder of Kurzweil Computer Products, Inc., Kurzweil Music Systems and Kurzweil Educational Systems with consultation from Stevie Wonder, twenty-five time Grammy Award winning singer, songwriter and music producer, as well as Lyle Mays, ARP founder Alan R. Pearlman, and others.

In 1982 Stevie Wonder asked Raymond Kurzweil if it was possible to create a keyboard instrument capable of utilizing acoustic as well as synthesized sounds and if that instrument could be utilized for live performance and studio use. Raymond Kurzweil utilized fundamental sampling concepts first engineered in reading machines for the blind (such as the Kurzweil Reading Machine) and adapted them for musical purposes. Reading machines work by sampling characters found in a document or text of some sort at pre-programmed intervals to reproduce a usable image of a document without any noticeable loss in intelligibility. The reading machine then converts the image into digital data (see:digitizer), stores the digital data onto Random Access Memory (RAM) and/or Erasable Programmable Read-Only Memory (EPROM) and presents the finished product as spoken text via a text to speech synthesizer. The Kurzweil K250 utilized a similar concept: Sounds were sampled, converted into digital data, stored onto Read-Only Memory (ROM) and are reproduced as sound. A prototype of the Kurzweil K250 was manufactured for Stevie Wonder in 1983. It featured Braille buttons along with sliders (potentiometers) for various controls and functions, an extensive choice of acoustic and synthesized sounds to choose from, a sampler to record sounds onto RAM and a music sequencer utilizing battery-backed RAM for compositional purposes. During production of the Kurzweil K250 at least five units were manufactured for Stevie Wonder.

The acoustic instrument sound sources found in the Kurzweil K250 (as well as the Kurzweil K1000 and K1200 series keyboards) were played by individual members from the Boston Symphony and other highly skilled musical artists. The Kurzweil K250 was officially unveiled to the music industry during the 1984 Summer NAMM trade show. Shortly thereafter the Kurzweil K250 was commercially manufactured until 1990 and was initially available as an 88-key fully-weighted keyboard and as an expander unit without keys called the Kurzweil K250 XP. A few years later into production a rackmount version called the Kurzweil K250 RMX also became available.

The Kurzweil K250 astounded the musical world with its ability to create realistic sounds of acoustical instruments. More astounding at the time was that it could play up to 12 notes simultaneously (also known as 12-note polyphony - see: Polyphony (instrument)) by utilizing individual sounds as well as layered sounds (playing multiple sounds on the same note simultaneously, also known as being multitimbral). Up to that point in time the majority of electronic keyboards utilized synthesized sounds and emulated acoustical instrument sounds created in other electronic instruments using various waveforms produced by oscillators. Five other manufactured digital sampled sound musical instruments were available at that time: E-mu Corporation's E-mu Emulator and E-mu Emulator II; Fairlight Corporation's Fairlight CMI; and New England Digital's Synclavier I and Synclavier II. However, there were major differences between the Kurzweil K250 and these other instruments:

  • The acoustic sounds contained in and produced by the Kurzweil K250 were so realistic tests were conducted with listeners blindfolded to differentiate sonic differences between a 9-foot grand piano playing and the Kurzweil K250 playing. Both were played through the same high quality $40,000 US dollar sound system. No differences were conveyed. [1] This was achieved despite the fact that the sounds in the Kurzweil K250 are 10-bit sampled sounds and utilized a proprietary sound contouring model to reduce memory requirements.
  • Multiple units could be connected together (in a daisy chain fashion) and played simultaneously with new technology at the time called MIDI - Musical Instrument Digital Interface. Not only was it possible to have a musician play the Kurzweil K250 as a solo, band or musical ensemble instrument; it could also be played as an entire band or even as an entire symphony orchestra! If twelve Kurzweil K250's were connected together, one could play 144 notes simultaneously, more than any symphony orchestra could produce simultaneously with all members playing at any moment in time. MIDI could also be used to transmit and receive other messaging in controlling the sound as desired.
  • SCSI technology is utilized in its system architecture, which was the fastest data transfer technology available at the time.
  • It utilized a Motorola 68000 32-bit 10 MHz processor, which was one of the fastest processors available at the time.
  • With the sampling option a sound could be sampled up to 50 kHz. (Such a high sampling rate, much higher than the highest frequency humans can hear, is needed because samples of sound at a given rate can represent at best half that audio frequency; see Nyquist frequency.)
  • The pitch of a sound could be transposed (see: transposition (music)) up or down using five different transposition modes without much change in timbre, as long as the transposition was not more than a few semitones.

The Kurzweil K250 was engineered with professional grade components. For example, the J12 connector on the back of the Kurzweil K250 where the power pod connects to the unit is similar to connectors used in the NASA Space Shuttle. It has a lock ring on a collar with a barrel connector. This was likely incorporated to withstand the ruggedness of connecting and removing the power pod/pedals from the instrument for performance. Other details, such as an array of multiple output options, a click track, a sync source (for synchronizing music with another device), an analog output board that produced inaudible noise levels with the widest amplitude (see envelope (disambiguation)) available (even at maximum volume), multiple sliders to assign multiple functions, the sampler previously mentioned and a twelve-track sequencer with advanced functionality were all state-of-the-art at the time of production.

The Kurzweil K250 was initially priced at $10,715 plus options (in 1983 U.S. dollars). Computer data storage (memory) along with costs in designing, engineering, research and development of such a revolutionary product contributed to it's high cost. Those who could afford the Kurzweil K250 enjoyed a musical composition, MIDI composition and performance instrument unparalleled to any other at the time. Even an Apple/Macintosh computer or a DOS-based personal computer could be connected to the instrument for sound modeling and musical compositional purposes. Almost 4,000 units were manufactured.

In the latter years of production two related instruments were also manufactured:

  • The Kurzweil K225 RMX. The Kurzweil K225 RMX was similar to the Kurzweil K250 RMX and it was more affordable. The Kurzweil K225 RMX contained about half of the sounds available on the Kurzweil K250 and utilized early production Kurzweil K250 hardware. In some cases a sticker identifying the unit as a Kurzweil 225 RMX was used instead of the standard silk screening imprinting.
  • The Hyper Kurzweil K250 [2] or [3]. Very little is known about this model other than the RAM cartridge was relocated to the left front panel, the right front panel possibly had other functionality (unknown), five additional buttons with some sort of SCSI functionality (unknown) were placed above the tuning control, 88 red LED's (Light-emitting diodes) were placed above each key (apparently to light up as the corresponding key was depressed), the manufacturer name KURZWEIL had raised letters instead of imprinted letters on the front panel and the slider caps were different (the slightly rounded edges were squared off). A SCSI hard drive may also have been added below the front right panel area. It is suspected this may have been one of the last Kurzweil K250's developed.

The Kurzweil K250 (with wooden keys) is heavy and bulky to move, it weighs 95 pounds (plus a few pounds for optional boards and components) and measures 57 inches length x 27 inches width x 9 inches height. The power pod weighs 22 pounds and measures 17¾ inches length x 11⅛ inches width x 4⅛ inches height. The Kurzweil K250 is used today by musicians in recording studios, movie studios, orchestras, ballet and theater companies (see ballet company), colleges and universities, Bell Labs (the research arm of Alcatel-Lucent), religious organizations, churches and Kurzweil K250 enthusiasts throughout the world.

Contents

[edit] Technical Specifications

  • 12-track music sequencer, polyphonic, 12,012 events (originally was 4,000 events and upgraded to 12,012 events except Expander units which offer 7,900 events), fully editable including quantization (see Quantization (music)), section call, sequence chaining, punch-in/out, mute/solo/fader automation, event editing, channel stealing, rhythm change, tempo change, MIDI and tape sync.
  • Tempo control, plus or minus up to 700 beats per minute (can be additionally manipulated if using the on-board sequencer), real time.
  • Chorus (five different modes - doubling, full chorus, flanging, echo and microtonal) with delay and detuning capability (all editable and adjustable), switchable in real time.
  • Transpose (five different modes - octave pitch shift, chromatic pitch shift, octave transpose, chromatic transpose and timbre shift) maximum range of 2 octaves up to 5 octaves down depending upon the mode selected, real time.
  • Fine Tuning (center position is concert or standardized pitch A=440), real time.
  • Brightness (of the sound), real time.
  • Sound volume, real time.
  • Volume swell, real time (see Expression pedal).
  • Tremolo, real time.
  • Vibrato, real time.
  • Sound velocity, both positive (increase) and negative (known as reverse velocity), real time (see keyboard expression).
  • Yodel capable (see Yodeling), real time.
  • Aliasing, real time.
  • Pitch bend, up or down, real time.
  • Touch sensitivity, real time.
  • Two sustain modes, normal sustain and sustained release (which is a quick dampening of sound after a note is struck), real time.
  • 96 non-destructive ROM sounds (basic sound block).
  • 341 presets.
  • 12 voice polyphony, 12 oscillators per voice, 256 segment amplitude envelope generator.
  • 16-bit multitimbral, 144 parts.
  • Fully assignable filters and envelopes.
  • 2 Low-frequency oscillators (LFO's) per voice, 24 multi-form LFO's total, all adjustable, 12 different adjustable options (see Low-frequency oscillation).
  • Variable sampling rate.
  • 18-bit floating point resolution.
  • Truncation, looping (see music loop), velocity crossfading.
  • Two separate signal buses (see electrical bus).
  • SCSI system architecture.
  • Separate outputs on both balanced XLR and 1/4 inch high and low power signal outputs as well as a 1/4 inch headphone jack.
  • Click track (built in metronome) for timing purposes, switchable on or off.
  • Trigger in via 1/4 inch jack.
  • Two full-size brass pedals built into the power pod (Typically used for sustain and sound dampening just like an acoustic piano).
  • Full size 88 note velocity-sensitive fully-weighted keyboard using lead weights in the keys (excluding RMX models).
  • Keyboards can be split, layered or set up with dual-amplitude. 87 split keyboards in one keyboard setup is possible. Approximately 40 user-created keyboard setups can be programmed, depending upon the keyboard types that are programmed.
  • MIDI capable IN, OUT and THRU with limitations on MIDI functionality (not MIDI GM standard - GM standard was implemented in 1991, one year after the Kurzweil K250 ceased to be manufactured).
  • Kurzweil K1000 remote mode capable with message display and remote button operation.
  • Main Unit Size = 54" width x 27" length x 9" height.
  • Main Unit Weight = 95 pounds plus a few pounds for optional components.
  • Power Pod Size = 11⅛" width x 17¾" length x 4⅛" height (283 x 451 x 105 mm).
  • Power Pod Weight = 22 pounds (10 kg).
  • Power input = 110-120 volts AC, 50/60 Hz, 380 watts (typical, an option was available for 220-240 volts AC). Later units had a different internal power supply and selectable 110/220 volts AC, 50/60 Hz, 380 watts.

[edit] Manufacturer Optional Components

  • Sampler: 16-bit sample rate of 5 kHz to 50 kHz, 100 to 10 seconds of sampling time respectively. Six different sampling modes: quick take, de-emphasis, slow decay, normal decay, fast decay and speech. Samples are fully editable. 1MB ROM standard. 1/4 inch microphone input jack for sampling source.
  • 2 MB SuperRAM (increases the sampling RAM available from 1 MB to 2 MB).
  • 4 MB SuperRAM II (increases the sampling RAM available from 1 MB to 4 MB).
  • Sound Block A - a.k.a "Expanded Basic Sound Block" (adds an additional 88 non-destructive ROM sounds).
  • Sound Block B - a.k.a "Rock Sound Block" (adds an additional 59 non-destructive ROM sounds).
  • Sound Block C - a.k.a "Orchestral Sound Block" (adds an additional 43 non-destructive ROM sounds).
  • Sound Block D - a.k.a "Horn Sound Block" (adds an additional 35 non-destructive ROM sounds).
  • Separate output board (providing twelve 1/4 inch jack discrete monophonic outputs in addition to the polyphonic stereo outputs). See Monophony and Polophony.
  • Plexiglas sheet music stand.
  • Performance (tubular) keyboard stand.
  • Volume swell pedal.
  • Daughterboard for installing up to two additional ROM sound blocks beyond the capability of adding four sound blocks.
  • Kurzweil 250 Quick Load System (QLS)
    • For Apple/Macintosh Computers (See: Apple Inc.) - Latest version is version 3.8. Will work with most Apple/Macintosh computers using Mac OS 6 - 9.2 (and possibly later, not verified) for use in uploading/downloading information to/from the Kurzweil K250 and working with that data. Data could also be viewed and/or manipulated using other third party software. A serial interface on the Apple/Macintosh computer is required; on early Apple/Macintosh computers (typical) it is known as a DB-9 connector or Mini-DIN 8 connector (typical) and on later Apple/Macintosh computers it is known as a Geoport, which is a Mini-DIN 9 connector. Some early Geoports using Mac OS 7.5.3 or earlier may not work with the Apple-supplied hardware driver - a driver that is known to work is the Opcode Open Music System 2.3.8 SerialDMA driver (freeware) available at: [4] If the Apple/Macintosh does not natively contain a DB-9 connector or Mini-DIN 8 connector or Geoport an adapter will be required for interfacing the K250 to the Macintosh—the only known third-party adapter is available at the GeeThree Stealth Serial Port adapter website: [5]
    • For IBM PC compatible personal computers (PC's) - See Third Party Optional Components below.
  • QLS cable for connecting the Apple/Macintosh DB-9 or Mini-DIN 8 (typical) or Geoport port to the Kurzweil DB-37 computer jack (DB-9 Male or Mini-DIN 8 Male or Geoport Male to DB-37 Male) -or- the PC DB-9 to the Kurzweil DB-37 computer jack (DB-9 male to DB-37 male).
  • QLS Modem Board (SCSI Board) - Apple/Macintosh or PC computer interface for saving/loading of samples, setups, keyboards, sequences and bins using QLS or MacAttach software (predecessor to QLS software for Apple/Macintosh).
  • Battery-operated 256 KB RAM cartridge and optional cartridge adapter kit for data storage and retrieval. (Note: Kurzweil indicated a cartridge kit is required, however it has been verified by the author of this article that the cartridge kit is not required if care is taken while inserting and removing cartridges to/from the cartridge slot).

[edit] Manufacturer Transitional Components

During the manufacturing of the Kurzweil K250 several improvements were made to the instrument. This section deals with typical updates and upgrades other than third-party additional components. For those who purchased the instrument later in the manufacturing run, expanded, improved and upgraded components as well as software updates were typically installed in the instrument (unless the instrument was older stock and was not upgraded for some reason). The following lists those components. For those who did not have a particular expanded, improved or upgraded component and/or software update and desired it, the item needed to be purchased and if necessary, installation charges were added, either by Kurzweil or by a third-party vendor. The following items are:

  • Software ROM upgrades. From the very early instruments to software version 4.X, then software version 5.X then software version 6.X. and lastly software version 7.1. These upgrades offered improved hardware and software functionality, signal processing improvements, bug fixes, maintenance improvements, feature additions/enhancements and increased reliability. The last known operating system created for the Kurzweil 250 was version 7.1 in 1989.
  • Hardware upgrades. The CGP (ROM) board was modified to allow additional ROM blocks and the processor board was modified for improved signal processing. The upgraded hardware was typically found in Kurzweil 250's manufactured in 1986 or later and was a highly recommended upgrade for older Kurzweil 250 units being upgraded to use version 5.X or 6.X software.
  • Power pod upgrades. Revised the type of power supply used and allowed for 110/220 volt AC selectable input.
  • Front panel button slider and button design and shape.
  • Front panel button labeling changes to match major software enhancements from software version 3.X to 4.X and later.
  • Complete Parallel SCSI Type 1 implementation in version 7.1. A 50-pin Narrow SCSI port was added above the computer jack on the rear of the K250. The K250 could then theoretically provide direct connectivity up to eight other SCSI devices (for example to connect directly to a hard drive without the need for a separate computer). It is not known if a pre-version 7.1 machine can be retrofitted to version 7.1.

Today either the end user has to install components themselves or a third-party vendor will need to install components since Kurzweil Music Systems no longer provides service or support for this instrument series.

[edit] Third Party Optional Components

  • Apple II computer or nearly any compact Macintosh computer (Macintosh 512 up to Macintosh IIci) computer using Mac OS version 6 (documented). A later model Macintosh with the proper interfacing hardware (GeoPort) and Mac OS 7 - 9.2 (and perhaps later OS's) has been proven to work.
  • MacAttach software for use in uploading/downloading information to/from the K250 using an Apple/Macintosh computer (this was superseded by QLS, which was available optionally by Kurzweil Music Systems). The data could also be viewed and/or manipulated using other third party software.
  • Sweetwater Sound Block SW800 - a.k.a. "Sweetwater Orchestral Sound Block" (adds an additional 54 non-destructive ROM sounds).
  • Sweetwater Sound Block SW900 - a.k.a. "Sweetwater Contemporary Sound Block" (adds an additional 52 non-destructive ROM sounds).
  • Various sampled sounds were available via the "Sweetwater network" that Sweetwater Sound established in the mid to late 1980s for the purpose of creating and swapping user-created sounds. Some of those sounds were incorporated on the Sweetwater SW800 and SW900 Sound Blocks.
  • Sweetwater Sound K250 Editor Librarian software. Required QLS and a separate MIDI interface from the K250 to the Apple/Macintosh computer.
  • Kurzweil Quick Load System (QLS) for PC's - (Note: Information about the following is not well known to the author of this article.) Latest known version is version 1.0 and it is not known if a later version was made for the PC. It is interesting to note Kurzweil Music Systems did not create QLS for the PC even though their name is on the label of the QLS 5¼" floppy disk. (It is not known to the author of this article the company that created QLS for the PC). It is not definitively known which PC platforms or operating systems this will operate on, even though it is suspected it will work on 286 and 386 computers using some early form of DOS. Like the Apple/Macintosh version it is used for uploading/downloading information to/from the Kurzweil K250 and working with that data. Data could also be viewed and/or manipulated using other third party software. A DB-9 serial interface on the PC is required.

[edit] Undocumented Functions

  • Mono Pressure - The User's Guide and Reference Manual indicates this feature is not available. However if the Kurzweil 250 is connected to a MIDI device not utilizing the Rock/Pop General MIDI standard (such as a real Church organ) this function can control the volume of that MIDI device independently of any other MIDI device connected utilizing the Rock/Pop General MIDI standard. This feature has been verified to work with Kurzweil 250 software version 6 by the author of this article.
  • Channel Stealing - If the parameters for "Steal Ahead with Sustain" (Function 10 -> STL4) and "Steal Ahead without Sustain" (Function 10 -> STL5) are both set to 11 apiece it is possible for the Kurzweil 250 to produce more than 12 notes simultaneously with certain keyboard sounds despite the fact there are only twelve analog channels available. This feature has been verified to work with Kurzweil 250 software versions 5 and 6 by the author of this article.
  • Sequence Chaining (natural, not silenced) using the on board sequencer without inserting a note release on the initiating sequence before chaining to the next sequence - This is very useful if chaining sequences which require note(s) to be held over from one sequence to another:
    • If the sequence being chained to contains a note release event corresponding to the note attack on the same track.
    • The track number utilized must be the same on both sequences.
    • Both tracks utilized must use the same keyboard setup during the period of time involved (the keyboard setup can change after the note release event).
    • Note: If utilizing MIDI OUT on the tracks involved undesired consequences may occur on the MIDI device connected as that device may not process the note release. This is because the MIDI device may not see a note release at the end of the first sequence involved possibly resulting in a hung note that may need to be reset manually. Some MIDI devices are able to accommodate this arrangement and others are not. It is possible to overcome this problem by utilizing this feature only for tracks not requiring MIDI and then if MIDI is required duplicate the track for MIDI only and insert a note release at the end of the first sequence (even though this may not produce a satisfactory result). This feature has been verified to work with Kurzweil 250 software versions 4, 5 and 6 by the author of this article.

[edit] Artists/Musical Groups Who Have Used The Kurzweil K250 With Articles On Wikipedia

Reference: Kurzweil 250 User's Guide, Pages 140 - 148 Appendix C: The Kurzweil 250 In the Real World Copyright 1988 Kurzweil Music Systems Incorporated [6] or [7]

[edit] References

  • Sound on Sound - Size Does Matter Kurzweil K250 Workstation Keyboard (Retro) [8]
  • Sound on Sound - Synth Secrets [9]
  • Biography of Ray Kurzweil [10]
  • Additional Article of Ray Kurzweil with picture of Stevie Wonder [11]
  • The Age of Spiritual Machines [12] or [13]
  • The Man and the Machine:An Interview With Ray Kurzweil [14]
  • Virtual Organ - Virtual Instruments:Joe Barron, Present at the 1984 NAMM Show when the Kurzweil 250 was introduced: [15]
  • What's New In Electronic Music; The Art Advances At Warp Drive: A. Arnold Anderson, New York Times [16]
  • Synthony's Synth & MIDI Museum [17]
  • Mastering the Kurzweil 250, Volume One: User's Guide and Volume Two: Reference Manual, Copyright 1988 Kurzweil Music Systems, Inc. [18]
  • Synrise - Brief information on the Kurzweil 250 (In German) [19]
  • Byrd, Donald, & Yavelow, Christopher (1986). The Kurzweil 250 Digital Synthesizer. Computer Music Journal 10, no. 1, pp. 64-86.

[edit] Audio

  • The Virtual Kurzweil 250 Sound Sheet - Play the 45 RPM Kurzweil 250 Demo Record virtually![20]
  • The Kurzweil 250 Rock Block - Play the 45 RPM Kurzweil 250 Demo Record virtually! [21]
  • The Kurzweil Rocks! - Play the 45 RPM Kurzweil 250 Demo Record virtually![22]
  • Christopher Yavelow - Countdown (For the Nuclear Age) - The Worlds First Computer Opera, completely synchronized from the baton of the conductor to the Kurzweil K250[23]
  • Christopher McGilton - Religious/Sacred Music in .mp3 format performed on the Kurzweil 250 and Yamaha MU-50/80 Sound Module [24] or [25]
  • Jane Brockman - Kurzweil Etudes excerpts in the tradition of Chopin performed on the Kurzweil 250, in three series:[26][27][28]
  • Steven Johannessen - Music Showcase at the Middle Of Nowhere [29]
  • Pamela J. Marshall - Spindrift Recordings - Noises, Sounds & Strange Airs, "Child's Play"[30]
  • Pauline Oliveros - Dear. John: A Canon on the Name of Cage[31]
  • Craig D. Tollis - The Happy Frog: Kurzweil K250 - Two demo recordings of the Kurzweil 250 [32]

[edit] Audio and Video

  • Ray Kurzweil - Ray Kurzweil Appearing on Worldnet - Demonstration of the Kurzweil 250 [33]
  • Keith Emerson - Emerson, Lake and Powell with Paul Schaffer and the CBS Orchestra on the Dave Letterman Show (Note that two Kurzweil K250's are being played live - one by Keith Emerson and the other by Paul Schaffer)[34]

[edit] External links

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