Blue Voice

New Timbral Oscillator (NTO)
The Serge Modular Systems NEW TIMBRAL OSCILLATOR (NTO) is the state-of-the-art VCO, featuring exceptional range, superb temperature stability, and accurate tracking. Dynamic depth frequency modulation and voltage control of waveform allow unprecedented control over a wide range of sound qualities.

• EXPONENTIAL 1 VOLT/OCTAVE RESPONSE - Exponential response parallels the response of human hearing perception as well as musical pitch structure. With multiple oscillators, each must respond exponentially to control voltages to allow transposition from key to key and to produce alternative equal-tempered tunings such as quarter and third tones. In addition, the one-volt-per-octave response assures that the New Timbral Oscillator is compatible with most keyboard and computer controllers.
• ACCURATE TRACKING - When two or more oscillators are tuned, it is expected that they will remain in tune throughout their entire range (in other words, that they track). Even two oscillators which track within a fraction of a semitone will be out of tune at the extremities of their range. Therefore, the New Timbral Oscillators have been designed so that any two will track within one cycle/second throughout their entire musical range.
• TEMPERATURE STABILITY - Instability of pitch with changes in temperature is the criticism of most synthesizer VCO's. Performers are aware of the disastrous effects of temperature when they must desperately retune oscillators that have drifted during a live performance. The temperature sensitive components are kept at an even 120 degrees by a solid-state "oven". Thus temperature stability is guaranteed from 50 degrees to 100 degrees F.
• WIDE FREQUENCY RANGE - The frequency range covers from below 16 to 16Khz. With control voltages, the range can be further extended from less than .1 Hz (10 sec/cycle) to greater than 100,000 Hz.
• VARIETY OF WAVEFORM OUTPUTS - In addition to three standard waveforms (sine, triangle and sawtooth) of exceptional purity, the New Timbral Oscillator offers a variable waveform output providing an amazingly varied range of sounds, unavailable on any other synthesizer. This waveform is voltage controllable, allowing dynamic control of sound quality.
• DYNAMIC DEPTH LINEAR FREQUENCY MODULATION - Dynamic depth frequency modulation is now available to the analog synthesist. Frequency modulation (FM), the modulation of one oscillator by another, generates both harmonic overtones (found in most acoustic instrument sounds) and non-harmonic overtones (bells, percussive, and electronic timbres). By varying the amplitude of the modulating oscillator, the richness or complexity of the sound can be varied. However, with conventional FM, an annoying pitch shift occurs. With the New Timbral Oscillator, Linear FM avoids this pitch shift, making it possible to maintain accurate pitch control while changing the quality of sound. A built-in VCA assures accuracy and provides dynamic voltage control of Linear FM Depth. Of course, conventional exponential FM is also available on the New Timbral Oscillator. The New Timbral Oscillator offers two voltage control inputs calibrated to one volt per octave and one variable voltage control input. One of the calibrated inputs incorporates a variable Portamento. This allows gliding from pitch to pitch at a voltage-controllable rate, set at each oscillator rather than from the controller (such as a keyboard), and therefore independently variable at each New Timbral Oscillator. All of the output levels are "hot", greater than +4 db to ensure maximum signal-to-noise ratio. A Sync input is provided for locking the NTO to another oscillator's fundamental, harmonic, or sub-harmonic frequency.

Precision Oscillator (PCO)
The Precision VCO is a versatile, voltage controlled oscillator offering three high quality waveform outputs (sine, triangle, and sawtooth) and both linear and exponential frequency modulation capabilities. A front panel switch conveniently extends the range of the PCO from the audio range (16 to 16,000 Hz) to a sub-audio range (.1 to 200 Hz) for use as a Low Frequency Oscillator.

• EXCELLENT RESPONSE, TRACKING AND STABILITY - Featuring the identical exponential response, exceptional tracking characteristics, and perfect temperature stability as the NTO, the PCO is especially suited for use with the NTO as a modulation source for dynamic depth linear FM.
• MANY FEATURES - Two calibrated one volt per octave inputs as well as a variable processing input are provided for complex frequency control. FM depth can be varied with the front panel adjustment. All output levels are "hot", greater than +4 db to insure maximum signal to noise ratio when used with subsequent processing. A Sync input is also available for locking the PCO to another oscillator's fundamental, harmonic, or sub-harmonic frequency.

Ring Modulator (RING)
Our new RING MODULATOR (RING) is a brand new design which incorporates greatly improved specifications. Features include the following:

• A VERY CLEAN SOUND down to very low signal levels (unlike conventional modulators where distortion increases at low levels).
• 80 DDS OF CARRIER SIGNAL REJECTION.
• INAUDIBLE NOISE OUTPUT.
• NO SQUELCH CIRCUIT IS REQUIRED due to the low noise characteristics, therefore annoying signal dropouts and “pumping” effects are totally absent.
• INTERNAL WAVESHAPING OF CARRIER to add to modulation effects

The sum total of these design improvements is a Ring Modulator capable of treating the most subtle acoustical signals, without the coloration typically associated with even the best previously available ring modulators. The versatility of the Serge Ring Modulator is enhanced by the added feature of voltage and manual control of the entire spectrum of modulation possible: from zero modulation (i.e. the original, untreated input signal) through amplitude modulation to full ring modulation. This allows many shadings of effect, manual or automatic with voltage controls. The ability to control the Carrier level manually and through voltage control allows the output to be level controlled as well. Through the use of an internal signal processor for the Carrier, additional effects can be produced by waveform modification of the carrier signal. When the module is set to full Ring Modulation from the lower knob or voltage control the output signal contains the sum and difference frequencies of the Signal Input and the Carrier Input. If both signals are pure sine waves (only one frequency component), the output will be a composite signal consisting of two frequency components: the sum and the difference frequency of the Signal and Carrier. If the Carrier level is increased beyond the mid-position, then the carrier waveform will become slightly rounded, and new frequency components will be produced. Each of these new components will also modulate with the Signal input to produce a sum and difference frequency, and the output signal will become richer in harmonics. This effect is unique to the Serge Ring Modulator, and allows another dimension in timbral modification. Although this module may be one of the most sophisticated in the SERGE system, it only takes up one inch of Panel space. (Recommended as companion modules placed near the RING MODULATOR are the various Preamps and VC Oscillators.)

Wave Multipliers (VCM)
For generating and modifying sound, the typical synthesizer patch is VCO-VCF-VCA, linked in series, with suitable control from keyboard, sequencer, or computer. The VCO generates the raw sound, the VCF dynamically varies the timbre (sound quality). and the VCA controls the amplitude and produces the envelope on the sound event. The Serge Modular WAVE MULTIPLIERS (VCM) provide a new link in this chain, representing an advance in synthesizer technology. In this typical patch, the Wave Multiplier could be placed just before the VCF. Like the VCF. the Wave Multiplier affects the timbre. Unlike the VCF, whose action is a subtractive process of filtering frequencies from the input waveform, the Wave Multipliers are able to dynamically process the input waveform to produce new harmonically-related overtones. This function should not be confused with Ring Modulation, since it is a non-linear process using a single audio input. Although it is possible to describe the effect of a VCF by saying the sound gets “bass-heavy”, makes a “wah-wah” effect, or sounds “thin”, describing the sound of a Wave Multiplier is much more difficult. The input sound comes out richer in harmonics, somewhat similar to pulse-width modulation and to linear frequency modulation, but with a new characteristic timbre. The nearest we can come to describing the unique sound qualities (there are three different sections) is to say that they alter the timbre in exciting new ways, producing interesting alternative forms of signal processing which are unique in the Serge Modular Music System. Since there are three entirely separate and different types of Wave Multipliers in this module, an enormously varied palette of new effects can be synthesized.

• The uppermost section is the simplest of the three multiplier sections. but it has two switchable effects. With the switch set at the “HI” position, the module functions to “square-up” an incoming signal. This is not the same as a simple comparator squaring function, though, since there is a rounded flattening of the signal peaks: an effect somewhat similar to overdriving a tube amplifier (except that in this version the process is voltage controllable!). With the switch in the “LO” position, the module is a linear gain controlled VCA. This is useful for various functions such as amplitude modulation and for gating signals into the other sections.
• The middle Wave Multiplier provides a sweep of the odd harmonics (1, 3, 5, 7, 9, 11, and 13th) when a sine wave is applied to its input and the knob is turned up or a control voltage is swept from low to high. This effect is similar to overblowing a wind pipe closed at one end, and thus the module can be used to produce the sounds of various wind instruments. A second input is included to allow two signals to be mixed before processing, a technique that we have found to be very usable. This module can be used to explore timbral areas beyond the range of ring modulation because there are more varied harmonics than the sum and difference tones.
• The bottom Wave Multiplier performs non-linear waveshaping known as full-wave rectification, but with sophisticated level-compensating conditioning as well. Actually the circuit uses three full-wave rectifier sections linked in a very refined controllable format. Each section can double the frequency of a sine or triangle wave applied to its input. Thus sweeping the VC input over its range will produce a smooth timbral transition using the even harmonics (second, fourth, and eighth). Many other partials are present in this basic sound, however, and the sonorities are very rich and varied. A notable feature of this multiplier is that the full-wave rectification is not accompanied by a reduction in the output amplitude. There is no alteration of the essential level of the sound. There are two inputs to provide mixing before processing, and two outputs. One output is a “squared up” version of the other. This output resembles voltage controlled pulse width modulation (only much more interesting).

The Wave Multipliers are among the most powerful timbral modifiers available on any analog music synthesizer. The rich varieties of inter-patch possibilities are nearly inexhaustible, and these possibilities combined with the flexibility of other Serge modules will provide unique synthesis tools for the person who is eager to experiment with entirely new classes of sounds. The Wave Multipliers provide what has too often been lacking in electric musics: a means of generating sounds as complex and dynamically variable as those found in acoustic sound sources. Yet these are also precision modules which respond accurately to control voltages, so they may be used to give repeatable results in the most exacting analog or digital applications.

Dual Audio Mixer w/ phase switch (2-3x1) (MIX2)
The Serge Dual Audio Mixer (MIX2) contains two independent mixers for audio signals. [Each section has three inputs with level control knobs]. [The top section is a three-in/one-out manual mixer with a phase switch on input 3]. [The bottom] section is a four-in/one-out manual mixer [with an additional] unity gain (non-attenuated) input. The main output of one section can be connected to the unity gain input of the other section to create larger mixing units. This module can be used as two audio mixers with three variable inputs, or as one mixer with six variable inputs. Used in combination with other mixers and VCA modules, various mixing functions can be patched.

Variable Q VCF (VCFQ)
The VARIABLE Q VCF (VCFQ) is an excellent general-purpose VCF offering simultaneous low-pass, high-pass, band-pass and notch (band-reject) outputs. The resonance (Q) of this filter is dynamically variable by manual or voltage control. The VCFQ has two signal inputs. One incorporates an automatic gain control to prevent the filter from overloading at high Q settings. The second input has a level control so that the percussive effects of overloading the filter can be exploited. When a pulse is applied to the Trigger input, the filter will ring, producing a damped waveform similar to that produced by striking a resonant object. The nature of this ringing is controlled by the Q and the filter frequency. Percussive effects ranging from clicks to the sound of wood blocks and bell tones can be produced and controlled. This ringing effect can be used in conjunction with signals applied to either of the audio inputs to achieve highly controlled complex tonal qualities.

[With the inclusion of the HI/LO switch, the VCFQ is actually the VCFX, described below]

Extended Range VC 'Q' Filter (VCFX)

In addition to the three VCF's, Serge Modular offers an EXTENDED RANGE VCF (VCFX) which is identical to the VCFQ except it features a second sub-audio range. This low-frequency range allows use as a control voltage processor. A fast envelope or trigger applied to the filter in the low range at high Q settings will cause low-frequency ringing, generating complex envelopes and damped vibrato effects. The VCFX can be patch programmed to oscillate by patching the band-pass output to the manual input. The outputs will be in quadrature relationships (90 degrees out of phase). 

Universal Audio Processor (UAP)
The UNIVERSAL AUDIO PROCESSOR (UAP) is the ideal VCA module for small Serge systems because it can function in the following ways:

• As two independent VCA's with separate signal and control inputs.
• As one equal-power stereo panner. This panner has one input routed to two outputs, in a proportion which is voltage controlled. The panner can be used for signal routing within a system or for the positioning of sound in a stereo field. A VCA controls the overall amplitude of the output signal.
• As a voltage controlled cross-fader. As one input signal increases in amplitude at the output, the other decreases.