Co-developed by and marketed in the US by Digital Keyboards Inc., the CRUMAR General Development System (GDS) offers both a complete sound synthesis laboratory and a high quality performance instrument in a single unit. Advanced logic design technology has been fused with state-of-the-art digital sound synthesis techniques to create a new dimension in real-time sound production. Intended as a tool for performing and studio musicians, composers, researchers and educators, the GDS emphasizes accuracy, flexibility and convenience. Precise digital computation of waveforms, envelopes and harmonics, coupled with studio-quality audio output, provides a degree of control not achievable with analog technologies. A wide range of musically meaningful parameters enables the immediate realization of a tremendous variety of sounds. These parameters, carefully arranged in logical groups, can be instantly allocated to sliders, rotary pots and switches, for fingertip control. The GDS is a completely digital synthesizer. Consequently, it is free from the problems of traditional analog units. Since the GDS is under the control of a supplied computer program, patches can be installed and changed quickly. Temperature sensitivity is also no longer a problem; the GDS does not have to be constantly retuned as it warms up. Most important, once the setting of a control has been established, it can be remembered exactly. Thus, a sound "found" can be saved and recalled for future use. The GDS uses a Z-80 microcomputer to supply data to special high-speed digital circuits that simulate the activity of 32 high-quality oscillators. The oscillator output is fed to a 16-bit, digital-to-analog converter to insure clean, recording-quality sound. A pair of double-density flexible disk drives provides fast storage and retrieval of voices, filters, recorded sequences and performance configurations. The unit is operated via a control panel with 65 input devices and a 61-note, velocity sensitive keyboard. A CRT terminal is included for instant display of parameters and key/pot settings. The GDS software is divided into two complementary programs. The Voicing program facilitates the interactive design of sounds and timbres with immediate audio feedback. A voice may utilize up to 16 oscillators, each with its own basic waveform and independent frequency and amplitude envelopes. These oscillators may be patched into various useful configurations. the keyboard. Chords are split up and presented one note at a time so that,for example, a chord can be changed from major to minor. A transposition mode allows an entire playing sequence to be transposed up or down as much as an octave by pressing a key in the lower two octaves of the keyboard. The current transposition will be "remembered" by the voices in the sequencer, even after the keyboard is returned to normal use. A "rhythm" control converts arbitrary timings to evenly spaced intervals, detecting the presence of chords and maintaining their integrity. In conjunction with the speed control, this feature provides a precise clock for recording "click tracks," et..

The Synergy is a fully digital keyboard-oriented sound synthesizer that incorporates many innovative features. The precision provided by the controlling computer and 32 completely digital oscillators allows the creation of extremely natural imbres in addition to standard synthesizer sounds. Individual strings with the "scratch" of the bow, plucked harps, and struck xylophones of unparalleled realism are available to the synthesist. A 74-key velocity sensitive keyboard is used to control both the amplitude and timbre of the sound. A pair of "sensitivity" controls - one for amplitude and one for timbre allow the dynamics of the keyboard to be continuously varied. The synthesist can therefore adjust the touch of the keyboard as desired. The timbre controls allow variations in the timbre - such as the "depth" of a leslie, speed of an echo, or brightness of the sound - to be determined by how hard the keys are struck, independent of the amplitude sensitivity.

A unique feature of the Synergy is the capability of playing up to four different timbres from the keyboard at the same time. Sophisticated progqram logic provides several modes for conveni ently controlling the assignment of timbres to the keys. In Unison, a note for each actdive timbre is started when a key is struck. In Rolling, each new key "rolls" to the next timbre in the selected sequence, round robin style. First Available facilitates voice, leading by selectin3 a timbre based on the number of keys currently down. Floating Split splits the keyboard into two ranges, but rather than having a fixed split pooint, moves the position of the split so that each timbre "tracks" the movement of one hand up and down the keyboard. Split allows the synthesist to select a fixed keyboard split point with a timbre on each side of the that point. Several hybrid modes are also available. In addition to the 24 pre proarammed timbres included with the instrument, a "cartridge" slot - much like that found on home video games - allows additional sets of 24 timbres to be available at the touch of a button. As new timbres are developed. they can be played by inserting new cartridges into the slot. Storage for up to 8 complete setting of the instrument ("programs") is included. This allows the synthesist to prepare desired settinas of timbres. etc. in advance and store them for immediate recall durina performance. The Synergy includes a fully digital built in four track event recorder, that allows the preparation of back ground accompaniment or simple recordings. Each track is polyphonic and polytimbral, and can be set to play through or loop continuously. The format is designed for easy overdubbing, and up to 1860 notes can be recorded. Because the sound i8 resynthesized on playback rather than just recorded various parameters can be changed dynamically, such as timbre balance, vibrato, transposition, speed (without altering pitch), and even the substitution of a fixed metronomic rhythm for the original rhythm.

The Svnergy has stereo outputs. Each timbre can be individually assigned to either the left, center, or right channels, or be set to "alternate" between the left and right channel when keys are struck. "Intelligent" polyphonic portamento can be set on each timbre, that gives the player the ability to control the sliding of many notes simultaneously. Notes can slide in any order, and in and direction, even "crossing' each other as they glide Three types of portamentc are available: smooth slide smooth slide withoul retriggering of the envelopes and semltone slide (glissando). In addition to the timbre and amplitude sensitivity controls described above, a variety of parameters can be adjusted individually for each timbre. The depth. rate and initial delay of vibrato or random pitch fluctuations; speed and type of portamento; transposition; stereo channel assignment. and monophonic/polyphonic state. Other features include a programmable pitchbend, which allows the player to set the maximum range of the control, and a "modulation" stick that introduces vibrato under fingertip control. The instrument includes a sustain pedal and a sustenato pedal, which functions like the center pedal on a piano. Normally eight notes are playable simultaneously though thls varies accordlng to the number of oscillators required for each note of the active timbres (there are 32 oscillators and most timbres requlre four oscillators). Up to sixteen notes are possible with 2 oscillator timbres. The state-of-the-art computer technoloqy incorporated into the Synergy provides a quality of sound and degree of flexibility not available with analog synthesizers. Only a brief overview of the main features of the machine has been presented here.