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Buchla Series 200 - The Electric Music Box

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    THE ELECTRIC MUSIC BOX, Series 200, is a comprehensive collection of precision electronic modules for generating and processing sound. It is a system designed for those who desire simultaneous control of many aspects of sound and who demand professional standards of performance and reliability.

    The system features unusually high functional density, extended dynamic range, self-contained monitoring (preview) facilities, and unrestrained expandability. Interesting new techniques for polyphonic signal generation, dynamic spectral and timbral modification, complex pattern generation, and control of spatial location and movement are introduced. Organization is optimized for compactness, ease of access, and ready comprehension.

    Connections within the system are made with color-coded patchcords, for maximum graphic visual feedback, zero crosstalk, optimal utilization of panel space, and unlimited flexibility and expandability. A clear and consistent distinction is maintained, both in modular function and in interconnection, between signals (the raw material of electronic music), control voltages (defining parametric structure, e.g. pitch, timbre, intensity, location), and timing pulses (defining event times and durations).

    Components of the Electric Music Box are designed to interface readily with digital computers. All musical parameters are voltage (and therefore computer) controllable; necessary logic supplies, tracking adjustments, and digital outputs are incorporated; and the prerequisites of high stability and predictability are met. Even the smallest Electric Music Box can be expanded to a hybrid digital-analog system incorporating programmed patching, multiple arbitrary function generation, and powerful editing and performance capabilities.

    The Electric Music Box can be configured to serve a variety of applications, including electronic music composition and performance, music education, psychoacoustic studies, environmental control, special effects generation, bio-feedback research, and video synthesis. Buchla and Associates can supply systems, auxiliary equipment and complete studios to suit these and other applications. For further information, please contact Buchla and Associates.


    Voltage control may be defined as the use of electrical voltages to determine the instantaneous values of musical parameters. The concept was introduced to the electronic music studio in 1963 (at the San Francisco Tape Music Center) and was instrumental in making electronic music composition a real-time process (instead of a tedious tape-splicing exercise).

    Voltage control has been generally applied to only two variables -- pitch and amplitude. And the sources of control voltages have been limited to relatively simple function generators, subsonic audio sources, and monophonic, dynamically unresponsive organ keyboards.

    The Electric Music Box extends voltage control to virtually every musical dimension. The system enables voltage control of pitch, amplitude, waveshape, filter parameters, envelope characteristics, modulation, reverberation, and quadraphonic location.

    Complementing this diversity of voltage-controlled parameters is a variety of control voltage sources. Touch-sensitive and electro-mechanical keyboards respond to the dynamics of playing; sequencers and envelope generators produce complex transient or cyclic patters. External signals interact through envelope and pitch detectors; the element of uncertainty is introduced by two specialized random voltage sources.

    In the Electric Music Box, a consistent distinction is maintained between control voltages (which define musical structure) and signals (the raw material of electronic music). This treatment of control voltage as an important, separate entity contributes significantly to the conceptual clarity and excellent technical performance that characterize the Electric Music Box

    204 Quad Spatial Director

    Voltage controlled quadraphonic distributor for determining the spatial location of sounds with pan pots or externally applied voltages. Monitor switches and voltage controlled attenuators are included.

    The 204s features include:

    4 electronically isolated 2-dimensional joysticks with output voltages proportional to lateral and vertical displacement. Generally used to control sound location, but may be used to control other parameters.

    4 gain controls for signals applied to inputs. Control voltages may alternatively be used to control amplitude.

    Control voltage inputs for defining positions of sounds. Increasing voltages move sounds from rear to front and from left to right. Voltages are generally (but not necessarily) derived from adjacent joystick outputs.

    Monitor switches for use in conjunction with the Model 226 Quad Monitor Interface.

    205 Matrix Mixer

    Two 5 in by 4 out mixers with provision for setting the amount of signal coupled from any input to any output. Commoned outputs provide 10 in by 4 out capability. Switches are provided for monitoring input signals through the Model 226 quad monitor/interface.

    The 205 matrix mixer is particularly useful for quadraphonic mixdown and distribution. Complex dynamic control of timbre can be achieved by inputting multiple oscillator or filter signals (additive or subtractive synthesis) and gating the outputs with a model 292 Quad Lopass Gate.

    206 Dual Mixer

    Two 3-channel mixers with separate and common outputs. Each input has associated level control, program switch, and monitor switch.

    207 Mixer / Preamplifier

    Replacing the model 206 Dual Mixer and the model 270 Quad Preamplifier, this unit combines a 6 channel stereo mixer and a single channel high-performance preamplifier. The mixer section offers voltage-controlled location capability and the preamp section accomodates a variety of source impedance and levels.

    208 Stored Program Source

    An integrated assemblage of functions designed to provide small Electric Music Box systems with an extensive and readily accessible vocabulary. To this end, the model 208 utilizes a new functional organization, a particularly rapid system of patching, and program storage via plug-in cards.

    The 208's primary signal source is the complex oscillator. This innovation applies a computer-developed technique of high-index bipolar modulation to the generation of complex audio spectra. The result is a timbral range unapproached by other musical instruments. Pitch, timbre, and waveshape are voltage controlled.

    A modulation oscillator serves as an additional signal source or can be used to frequency or amplitude modulate the complex oscillator. Frequency and modulation index may be voltage controlled; mode and waveshape are switch selected. signal enveloping is accomplished with two lopass gates, unique for their ability to gate in the frequency domain, the amplitude domain, or both simultaneously.

    The 208's control voltage section includes a five-position sequencer with programmable pulse outputs and a random voltage generator with four uncorrelated voltage outputs. An envelope generator has voltage controllable attack, duration and decay times, and a voltage controlled pulser provides trigger pulses and additional envelope voltages.

    The 208 provides the capability for permanent storage and immediate retrieval of complete instrument definitions (patches) or portions thereof. (An "instrument definition" includes settings of parameters, degrees of articulation, switch positions, and interconnections.) Storage entails the installment of resistors on program cards; retrieval is accomplished by plugging in a desired program card and activating a switch.

    A preamplifier allows external signals (mike, instrument, or line level) to be introduced and modulated, filtered, or otherwise processed. An envelope detector permits such signals to control various aspects of the 208's operation. An output section provides for mixing, reverberation, monitoring, and final level adjustments. A two-watt monitor output will drive headsets or low level speakers.

    The models 208 Stored Program Sound Source is supplied with six blank program cards, an assortment of programming resistors, and a comprehensive instruction manual. It occupies four panel units.

    212 Dodecamodule

    The Dodecamodule Model 212 allows even the smallest Electric Music Box system to incorporate the sophistication and diversity of function formerly available only in large studio systems.

    Model 212 integrates the following 12 functions into one compact module:

    A low-noise preamplifier for amplifying signals from microphones and instrument pickups. Gain is 35 dB; input impedance is 1 mega-ohm; connector is standard phone.

    Noise source
    A source of unpitched noise with high (+3 dB/octave) and low (-3 dB/octave) spectral distributions.

    Envelope detector
    Generates a control voltage proportional to applied signal amplitude. Output pulse and indicator are activated when input signal level exceeds 0 dB.

    Stored random voltage
    A source of unpredictable control voltage that changes when a pulse is applied. Probability distribution (over control voltage range) is flat; correlation is zero.

    Random voltage source
    A source of continuously changing random voltage with a modified Gaussian probability distribution and voltage-controlled spectral bandwidth (probable rate of change).

    Balanced modulator
    Voltage-controlled, balanced modulator enables continuous transition from unmodified to amplitude-modulated and ring-modulated signals. Unit features exceptionally low distortion (.5%) and high carrier rejection (65 dB).

    Voltage-controlled filter
    A voltage controlled bandpass filter with processing inputs for both center frequency and bandwidth. Center frequency range is from 30 Hz to 15 kHz; bandwidth range is from 1 semitone to 4 octaves. Unit has modulation input, resonance control, exceptionally low noise and high dynamic range.

    A nice, simple 3-input mixer.

    Headset driver
    Five-watt stereo amplifier for driving headsets or low-level monitor speakers

    Triple envelope generator
    Three pulse-activated envelope generators with variable attack and decay times and a choice of sustained or transient operation. Pulse outputs permit cascade or feedback modes. Range of attack and decay times is from .001 to 10 seconds.

    Triple lopass gate
    Three voltage-controlled gates with selectable amplitude-dependent spectral characteristics.

    Output amplifier
    Stereo output section for final mixing and line driving. There are 3 inputs, each with gain, stereo location, and reverberation controls. One each of these parameters is voltage-controlled for enhance flexibility.

    217 Touch Keyboard

    A combination of four separate touch sensitive controllers, each with a variety of pressure and position activated outputs.

    The Model 217 includes a 17 note electronic keyboard with both tunable and equal interval outputs. All pulse and pressure outputs are activated by any key: separate pulse outputs are triggered by individual keys.

    A similar 4 key section has the above features plus individual pressure outputs for each key. Two analogue controllers provide output voltages that are proportional to lateral position.; they also feature pressure and pulse outputs.

    The Model 217 incorporates design features that assure logical and responsive operation. Output voltages are "remembered" when a finger is lifted, the output remains at the last value; keys do not "block" the sustaining of one key does not inhibit the action of another: functions are activated by body capacitance, providing a level of responsiveness and reliability unavailable with mechanical or resistance sensitive keyboards.

    218 Touch Keyboard

    A 29-note (2-1/3 octave) chromatic keyboard appropriate for small and medium sized systems. Contains a 3-valued preset section which may be used independently or to shift the pitch output voltage by octave of preset intervals. Pressure, pulse, and voltage-controlled portamento outputs are included.

    219 Touch Keyboard

    A 4-octave keyboard with eight separate sections and a total of 38 outputs -- sufficient functional density and diversity to facilitate responsive control of elaborate configurations

    The main section has 48 touch-sensitive keys and both monophonic and polyphonic voltage, pressure, and pulse outputs. Voltage outputs can be offset or modulated by applied control voltages or audio signals. Two, three, or four voice polyphony can be implemented. Polyphonic operation is musically logical -- a sustained voice is not "stolen" by a trill; pressure outputs respond only to the activating keys.

    An 8-key section has individually tunable keys, both separate and common pulse outputs, and equal interval voltage output and status indicators. It finds applications in selectively initiating events, addressing segments of function generators and altering modes and tunings.

    Two joysticks with X and Y outputs provide single point control of two variables (modulation frequency and index, for example). When plugged into a model 227 System Interface, the offer a convenient means for locating sounds in quad space.

    Additional resources include three keys with individual pulse and pressure outputs, and a bipolar control voltage output, particularly appropriate to pitch-bending and vibrato. Buffered digital output, for interfacing to digital processors, are also provided.

    221 Kinesthetic Input Port

    Replaces keyboard models 218 and 219, with several technicial and functional improvements and additions which enhance musician-instrument communication. Thee 221 can simultaneously serve as a performance and programming facility for 300 series systems.

    226 Quadraphonic Monitor/Interface

    Provides for monitoring, interfacing, and final program formatting in four-channel systems. Built-in provisions for quad mixing, duplications, and overdubbing simplify the manipulation of quadraphonic material.

    The 226 has 16 program inputs organized in four groups of four. The level of each group can be voltage controlled or manually set. The mixed output appears at the back of the unit for connection to tape recorders or program lines.

    Monitoring is accomplished with self-contained level meters, headset drivers, and external power amplifiers and speakers. All quad inputs, as well as the program output, can be monitored -- selection and status indication are via lighted pushbutton switches.

    Many 200 series modules are equipped with switch that enable expedient monitoring of signals throughout a system. A jack field facilitates interfacing external components (radio, phono, etc.) and provides for multiple signal connections.

    227 System Interface

    The model 227 System Interface facilitates the equalization, location, mixing, monitoring, and routing of audio signals in 4-channel studio or performance environments.

    There are a total of 12 signal inputs. Four are primary inputs, with associated bass and treble controls, reverb send pots, and locations or assignment controls. The remaining eight are organized as two quad busses, can be normalled from tape decks, and are used for mixing and dubbing when no further processing is desired. Locations and movement can be governed by applied control voltages; indicators are provided to display activity and to aid in accurate track assignment.

    Two quad outputs are provided -- the program bus and the monitor bus. In studio applications, the program bus is typically routed to tape recorders, and the monitor bus drives a quad sound system. In performance situations, the program bus drives the sound system, and monitoring (preview) is accomplished via the headset output.

    The monitor function is activated with toggle switches. Points that can be directly monitored include the program output, the reverb return, each of the 227's inputs, and various mixer inputs within the system. Monitor status is indicated with solid state light emitters. VU meters are driven from the monitor bus.

    The 227 is equipped with an internal spring reverb; and external reverb unit (mono, stereo, or quad) may be patched in if desired.

    All lines to and from the system (up to 29) connect through a single front panel receptacle, thus allowing rapid and accurate disconnection and reconnection of a system from its environment. Adaptors for miniphone and solder terminations (for fixed installations) are provided.

    230 Triple Envelope Follower

    Produces control voltages proportional to the amplitudes of applied signals. Unit has a wide dynamic range and can be used in conjunction with a Model 292 Lopass Gate to accurately transfer envelopes from one signal to another. Decay time is adjustable from .1 to 5 seconds.

    In the direct coupled mode, pulse outputs are activated when corresponding control voltages exceed 6 volts. Transient coupling permits the detection of attack transients in the presence of background noise and over a considerable range of amplitudes.

    [Early models produce pulses above 7.5 volts and featured switchable linear/exponential detector slope in lieu of the direct/transient coupling feature]

    232 Frequency Detector

    * Polyphonic * Velocity Sensitive * Pressure Sensitive

    These keyboards provide the musician with the means to achieve direct expressive control of the Electric Music Box's many voltage-controlled parameters.

    Model 237 (pictured) has 37 keys (3 octave) and 3 voice polyphonic outputs; Model 238 has 61 keys (5 octaves) and 4 voice polyphonic outputs. built-in processor allows polyphonic output voltages to be transposed or modulated by applied signals and control voltages.

    Both models feature velocity and pressure outputs. Velocity output voltages are proportional to initial striking force; pressure outputs are actuated by applying pressure at bottom of key travel.

    Key voltage outputs are equal interval -- any equal-tempered scale may be readily tuned with the processing and offset controls built into Electric Music Box oscillators. (Keyboard model 238 can produce any 12-note scale with the help of a Model 246 programmed voltage source)

    A separate 6-note, tuned voltage source with individual pulse outputs (useful for presets and event initiations) is incorporated in both models. Model 238 includes a digital output for interfacing with digital computers.

    237 Polyphonic Keyboard

    The Sequential Voltage Source is an analogue memory for storing and retrieving control voltages. It includes an electronically separate pulse generator with voltage controlled period and pulse length (duty cycle).

    The Model 245 produces up to 5 programmed voltages at each of four outputs. Other then the number of stages the 245 is identical to the 246 ,see the 246 description for more information.

    238 Polyphonic Keyboard

    The Sequential Voltage Source is an analogue memory for storing and retrieving control voltages. It includes an electronically separate pulse generator with voltage controlled period and pulse length (duty cycle).

    The Model 245 produces up to 5 programmed voltages at each of four outputs. Other then the number of stages the 245 is identical to the 246 ,see the 246 description for more information.

    245 Sequential Voltage Source

    The Sequential Voltage Source is an analogue memory for storing and retrieving control voltages. It includes an electronically separate pulse generator with voltage controlled period and pulse length (duty cycle).

    The Model 245 produces up to 5 programmed voltages at each of four outputs. Other then the number of stages the 245 is identical to the 246 ,see the 246 description for more information.

    246 Sequential Voltage Source

    The Sequential Voltage Source is an analogue memory for storing and retrieving control voltages. It includes an electronically separate pulse generator with voltage controlled period and pulse length (duty cycle).

    The Model 246 produces up to 16 programmed voltages at each of four outputs.

    The Sequencer employs three methods of selecting stages; pulse advancing, analogue selection, and pulse selection. All can be used simultaneously or in any desired combination.

    Pulse advancing is used for generating sequences of control voltages. A pulse derived from the self contained pulser or from an external source advances the sequencer one step. sequencers may be cyclic over a number of stages or may be single shot, beginning and ending on any desired stage. Sequence boundaries are established by switches located between stages.

    An analogue select input permits the value of an applied control voltage to determine the activated stage. Higher voltages select higher numbered stages; zero volts enables the pulse advance and pulse select inputs. Analog selection is particularly useful for converting a continuous voltage (from an envelope Generator or detector or a random voltage source) into a series of pre selected values (a 12 tone scale for example). It also enables indirect addressing by another sequencer and facilitates simple (one patchcord) extension of the Model 217 Keyboard's number of programmable outputs to 5.

    The sequencer may be employed as a preset controller (a random access memory), with pre selected parameter values recalled by applying a pulse to the input of the desired stage. This pulse selection, used in conjunction with pulse advancing, allows several transient or cyclic sequences (different rhythms, for example) to be simultaneously programmed. A desired program might be initiated by pulses from a keyboard or another sequencer.

    Light emitters and pulse outputs are energized as corresponding stages are actuated. The period of the self contained, voltage controlled pulser has a range of .005 to 10 seconds. Pulse width can be varied from 1% to 100% of the period.

    248 Multiple Arbitrary Function Generator

    The defining of audio parameters by means of voltages is an important aspect of modern electronic music instrumentation. But the usefulness of this principle is determined by the flexibility and generality of control voltage sources. Since their introduction in 1963, envelope generators and sequencers have comprised the available programmed sources of control voltages. Even with a decade of refinement they possess significant shortcomings. Envelope generators (developed to establish traditional note shapes) produce only a specific class of simple transient functions; sequencers (developed to reduce tape splicing) are limited to stepped functions and rigidly phased outputs. The resultant constraints on our otherwise quite general system led us to conceive this new source of programmed voltages. Unencumbered by engineering expediency or presumed musical aesthetics, the model 248 provides the musician with an unprecedented degree of control over the dynamic aspects of his music.
    Functions are defined as point to point interpolations - the musician enters the voltage and interval time for each segment; the instrument accurately executes the implied interpolation. Times may range from .001 to 120 seconds; maximum number of segments is 16 or 32. Individual segment times and voltages may be governed by external voltages, permitting the implementation of higher ordered modes of voltage control such as indirect analogue addressing or voltage control of attack and decay times. Programmed output pulses may accompany the functions in any desired pattern; various additional control modes may be implemented.

    Each output section contains a time based multiplier (controlled from the panel or via applied voltages) and the logic necessary to start and stop a local clock via program control, panel switches or applied pulses. Preset and reset logic is also incorporated; stage selection may be performed manually or by application of control voltages or pulses.

    In addition to the main control voltage output, each output section includes a "time" output (voltage proportional to internal time), a "reference" output (descending ramp, with period equal to interval time), an "all pulse" output (activated for each segment of a function), and two programmed pulse outputs.

    The 248 may be regarded as a memory with 16 or 32 addressable storage locations, and a number of output ports, each of which can output the information contained in any portion of the memory. Each memory location contains the analogue and digital information required to define a segment of a time varying function; an output can produce a function consisting of any desired series of predefined segments. A unique and essential characteristic of the 248 is that it can operate asynchronously - that is, different output sections can simultaneously generate identical or dissimilar functions with completely different time scales and/or phase relationships.

    256 Dual Control Voltage Adder

    Allows several control voltages to simultaneously affect a single parameter. Up to four applied voltages can be scaled and added (or subtracted) to (or from) an internally generated offset voltage. [Note that processing inputs provided on series 200 modules are generally sufficient; the 265 is needed only for implementing unusually complex control modes in large systems.]

    257 Dual Control Voltage Processor

    Consists of two identical sections, each of which permits several applied control voltages to define a single output voltage according to the equation:

    V_a * K + V_b * (1 - M) + M * V_c + V_offset = V_out

    The algebraic manipulations possible with this module include addition, subtraction, scaling, inversion, and multiplication. Also incorporated is the capability of using one control voltage (M) to transfer control from one applied voltage (V_b) to another (V_c).

    258 Dual Oscillator

    Two independent voltage-controlled oscillators, continuously tunable from 5 Hz to 20 kHz. Each has two processing inputs and a frequency modulation input. Waveshapes as well as frequency can be voltage controlled. Model 258 oscillators feature low sine wave harmonic content, negligible settling error, and high short and long-term stability, even with rapidly changing ambient temperatures.

    Controls and I/O

    Processing inputs
    Two processing control inputs permit multiple control of pitch without need of separate external processor.

    Processing controls
    Used to set desired range of frequency control. Expansion, compression, and inversion of scales are accomplished here.

    Frequency modulation control
    For adjusting vibrato depth or creating clangorous or bell-like tones, rich in non-harmonic partials.

    Signal amplitude is +4 dB. Output impedance is 600 ohms.

    Oscillator frequency control
    Spans the audio spectrum of 5 Hz to 20 kHz with no range switching. (Applied control voltages can extend limits to .1 Hz and 30 kHz.)

    Waveshape control input
    Waveshapes can be varied from sine to saw (osc 1) and sine to square (osc 2). Voltage control of waveshape enables powerful dynamic control of timbre.

    259 Programmable Complex Waveform Generator

    The model 259 Programmable Complex Waveform Generator introduces several innovative techniques for dealing with complex timbres. It features voltage controlled modulation of pitch, amplitude and timbre, multi-dimensional voltage-control of timbre space, phase locking, automatic tuning, and (simultaneous or separate) local (front panel) and remote (digital) control of all functions.

    264 Quad Sample-And-Hold/Polyphonic Adaptor

    Four independent sample-and-hold circuits, plus a specialized logic circuit for expediently implementing polyphonic patches.

    Sample-and-hold's are essentially one-cell analog memories. They are useful for "remembering" tine instantaneous value of a control voltage (a detected envelope, for example), for generating equally space steps from a constant slope input (as from a 280 Envelope Generator), and for converting any continuously changing voltage (a random voltage, for instance) into a series of discrete values.

    The 264's sample-and-hold circuits have two operating modes: sample and track.

    In the sample mode, the value of the input is sampled and applied to the output whenever a pulse is received. The output remains at the value until the next pulse arrives. The track mode differs in that an input is applied to the output for the duration of the pulse. The output tracks the input until the end of the pulse and remains at a constant value until the next pulse. The Model 264 includes a polyphonic adaptor, which performs the logic necessary to implement four-voice polyphony. Facilities are incorporate for fine tuning and f.m. modulation the oscillator; light emitters display the adaptor's operation.

    265 Source of Uncertainty

    Generates two continuously varying random voltages, two pulse actuated unpredictable voltages, and audio noise with three spectral distributions.

    The bandwidth (probable rate of change) of the varying random voltages is voltage controllable over a range of .05 to 50 Hz, making possible changes that range from barely perceptible movement to rapid fluctuation.

    The output of each random voltage source is a constant voltage; this voltage assumes a new unpredictable value each time an input pulse is applied. Variable correlation limits successive changes without altering range.

    Noise comes in three flavors. White noise is electrically flat, but acoustically balanced toward the high end of the spectrum (+3 dB/octave). Integrated white noise has a low spectral bias (-3 dB/octave). Musically flat noise has a flat spectrum (constant energy per octave) and is a particularly useful source for subsequent processing.

    266 Source of Uncertainy

    Replacing the model 265 Source of Uncertainty, model 266 provides, in addition to the functions of the 265, voltage control of probability distribution and quantization, a voltage controlled integrator, and a specialized sample and hold.

    270 Quad Preamplifier

    Four separate high-gain, low-noise preamplifiers with individual line level outputs and a mixed output. Input impedances are switch selectable; both high-impedance sources (crystal mikes, high-impedance dynamic mikes, instrument pickups and low-impedance balanced mikes may be accommodated.

    275 Dual Reverb / Equalizer

    Two electronically separate units for reverberating and equalizing audio signals. Monitored inputs, separate reverberated and equalized outputs, and a voltage controlled mixed output are provided.

    The reverb section employs specialized circuitry, shielding, and mounting provisions to insure low distortion response and extended spectral and dynamic range. Tone controls have a range of +/- 10 db at 50 Hz and 10 kHz.

    Reverberation is voltage controlled, with two operating modes. In near mode, increasing voltage simply increases the degree of reverberation. In the recede mode, the control voltage affects the amplitude as well as the reverberation. A sound appears to approach with increasing voltage and recede. (into oblivion) with decreasing voltage.

    The reverberation electronics and delay elements are remotely mounted. Interconnections are at line level, permitting the use of the control module with reverb units of alternate origin (E.M.T's for example)

    280 Quad Envelope Generator

    Four independent envelope generators with variable attack and decay times (range is .001 to 10 seconds) and a choice of sustained or transient operation. Input pulses initiate envelopes and optionally control duration time; output pulses, activated at end of decay, are particularly useful for advancing sequencers or looping to inputs to generate repetitive functions.

    281 Quad Function Generator

    The model 281 Quad Envelope Generator replaces models 280 and 284, and features independent voltage control of times, expanded time ranges (.001 seconds to 5 minutes), quadrature outputs, internal looping for repetitive function generation, remote control for digitally aided systems, and combining networks for creating complex transient functions.

    284 Quad Voltage-Controlled Envelope Generator

    Adds voltage control and variable delay and duration times to the capabilities of the Model 280. All times are internally variable from .002 to 10 seconds; control voltages may be used to extend this range and control overall time while preserving envelope shape.

    285 Frequency Shifter / Balanced Modulator

    Shifts frequencies contained in input signal by an amount equal to externally applied or internally generated reference frequency. Internal reference generator is voltage-controlled, frequency-modulated, and provides the capability of continuous shifting through zero. Raised and lowered frequencies are simultaneously available. Unit incorporates a separate, voltage-controlled, balanced modulator, providing continuous transition from unmodified to amplitude-modulated and ring-modulated signals.

    291 Dual Voltage-Controlled Filter

    Two bandpass filters with voltage-controlled center frequencies and bandwidths. Center frequency range is from 30 Hz to 15 kHz; bandwidth range is from one semitone to four octaves. Offset controls are used to set initial parameter values; processing controls establish range and direction of applied control voltages. Unit has modulation inputs, resonance controls, exceptionally low noise and high dynamic range.

    292 Quad Lopass Gate

    Four independent gates with selectable amplitude-dependents spectral characteristics. Knob settings and applied control voltages determine levels and cutoff frequencies. A summed output facilitates voltage controlled mixing.

    The Model 292, with the capability of simulating the spectral and amplitude changes that accompany a receding sound source, is one of several Electric Music Box modules that can deal with spatial localization and movement. [Others are the Model 227 System Interface and the 285 Frequency Shifter/Balanced Modulator (for Doppler shift).]

    Frequency domain gating can impart a dynamic tonal variation to sounds that gives the listener a sense of absolute loudness. This quality is characteristic of all acoustic instruments (the harder you strike, pluck, or bow, the richer the overtone structure), but has been lacking in electronic instrumentation.

    294 Four-Channel Filter

    A bandpass filter with sharp cutoff slopes (20 dB/octave) at crossover frequencies of 250, 1000, and 4000 Hz. Individual filtered outputs are unattenuated; summed output has adjustable spectral shape.

    295 Ten-Channel Filter

    Ten-channel comb filter with center frequencies selected to complement the discrimination curve of the human ear. Separate unattenuated outputs and a summed output, with adjustable spectral shape, are provided. This unit is particularly useful for graphic equalization and (in conjunction with a Model 205 Matrix Mixer, a 248 Function Generator, and a 292 Lopass Gate) for generating complex, time-varying timbral functions.

    296 Programmable Spectral Processor

    A 16 channel filter with channel frequencies selected to complement the discrimination curve of the human ear. It features enahnced rejection of out-of-band frequencies, and provision for operation as two isolated 8 band filters. It includes a complete facility for performing spectral analysis, synthesis and transformations under panel control, or with the aid of a 300 series processor (or both simultaneously).
    Type: Analog, Digital
    Synthesis: Additive, Frequency Modulation, Subtractive
    Oscillators: *
    Waveforms: Pulse, Pulse Variable, Saw Down, Sine, Square, Triangle
    Envelopes: *
    Evelope Paramerters: Attack, Decay, Sustain
    Filters: *
    Polyphony & Tuning
    Polyphony: *
    Timbrality: *
    Tuning: Atonal
    Patches RAM: 1
    Case: Desktop
    Audio Output Connections: 1/4" Phone Jack, 1/8" Phone Jack, Mono Out, Stereo Main
    Year Released: 1970
    Manuals & Documents

    Product Links
    Company Product Sites:
    MSRP List Price: * - convert
    YouTube Videos
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