XAOC 1955 Transcendent Waveform Analogue Oscillator Instruction Manual
- June 12, 2024
- Xaoc
Table of Contents
XAOC 1955 Transcendent Waveform Analogue Oscillator Instruction Manual
Module explained
SALUT
Thank you for purchasing this Xaoc Devices product. Sofia [ˈsɔfja] is a fully analog voltage-controlled oscillator (VCO) based on an original waveforming principle. It features a modern, well-calibrated, temperature compensated triangle core and two elaborate waveshaping and modulating sections. The sound is a mixture of a warm, saturated base tone and two ripple components. Besides its main output, Sofia offers access to individual components of the sound plus a multitude of modulation inputs allowing for extensive self-patching and animation of the waveform. To better understand the device, we strongly advise the user to read through the entire manual before using the module.
INSTALLATION
The module requires 24hp worth of free space in the Eurorack cabinet. Always turn the power off before plugging the module into the bus board using the supplied ribbon cable. Pay close attention to power cable pinout and orientation. The red stripe indicates the negative rail and should match the dot or –12V mark on the bus board as well as the unit. Sofia is internally secured against reversed power connection; however, rotating the whole 16-pin header may cause se
fig. 1: example waveforms
Rious damage to other components of your system, because it will short circuit the +12V and +5V power lines. Always pay close attention to the proper orientation of your ribbon cable on both sides! The unit should be fastened by mounting the supplied screws before powering up.
OPERATING PRINCIPLE
Sofia implements and extends the classic computer music method for synthesis of formant sounds called FOF (fonction d’onde formantique), which uses a combination of simple, time-domain components (decaying sinusoidal waves) to achieve desired spectral characteristics (see infobox, page 7).
In Sofia, two of such ripple elements are added on top of a slightly saturated sinusoidal base tone. Each new cycle of the
Front panel overview
base tone spawns a new pair of ripple elements. The ripples’ density and decay rate may be adjusted over a wide range. Additionally, the elements may be warped so that their density accelerates or decel – erates within the cycle. Finally, their basic waveform may be switched from sine-like to square-like for additional richness.
Despite the seemingly divergent fre – quencies present in the signal, it re – mains strictly harmonic due to how all elements are waveshaped from the core tone and therefore phase coherent. Thus, Sofia is not a complex oscillator in the Buchla sense; however, it goes beyond the traditional set of primary waves and wavetables, hence the name.
MODULE OVERVIEW
The front panel of Sofia (fig. 2) offers direct access to all parameters in a oneknob-per-function arrangement. The big, central pitch knob 1 offers continuous pitch control in the range of two octaves, while the rotary octave switch above it 2 offers eight additional octaves with the lowest lo position referring to sub – sonic frequencies. The pitch frequency is also controlled via the pitch cv v/oct input 3 , which accepts voltages from –10V to +10V. However, the usable range of voltages depends on the position of the manual controls. The entire frequency range of Sofia extends from about 0.4Hz to 12kHz for the fundamental tone and well into ultrasonic range (over 120 kHz) for the ripple elements. Besides V/Oct control, Sofia also offers two adjustable CV inputs for modulating pitch frequency: pitch fm 4 and global fm 5 with their corresponding attenuators. The main difference between these two is that pitch fm preserves the shape of the waveform, while global fm preserves the overall spectrum, mainly affecting the frequency of the base tone.
Situated on each side of the pitch controls are two knobs dedicated to component mixing. The left knob 6 adjusts the mix balance between the two ripple elements (a and b), offering 1:1 proportions in the middle. The corresponding CV input labeled elements mix 7 accepts voltages in the -5V to +5V range, adding an offset to the manual setting. The right knob 8 controls the balance between the fundamental tone and the ripple elements. There is just the base tone in its minimum position and just the elements without the base tone in the maximum position. The corresponding CV input labeled fund·elem mix 9 accepts voltages in the -5V to +5V range, adding an offset to the manual setting
Most of the remaining potentiometers and jacks correspond to individual ripple elements (a and b) and offer identical controls over their parameters on each side of the panel. The red ratio knobs 10 define how dense the ripples are relative to the fundamental tone. At the minimum position, there is no ripple, just a single parabolic fold squashed by the decay curve. Increasing the ratio adds more cycles to the wave, thus shifting the frequency of the corresponding formant further from the fundamental frequency. At the maximum position, about 240 ripples yield a spectral peak 8 octaves above the fundamental frequency. The two ratio inputs 11 with their corresponding attenuators 12 facilitate continuous modulation with external bipolar control voltages.
The damp parameters control the decay rates of the ripples, which are adjusted by the slider potentiometers near the edges of the panel 13 and their corresponding CV inputs 14 , which act as offsets. At the minimum position, narrow spikes are generated (about 1% of the fundamental period), while at the top position, the decay is sufficiently slow, so the ripple amplitude decreases only slightly along the cycle. note: while these controls behave like parameters of a resonant filter (resonant frequency and resonance/ damping), the actual signal is not obtained through filtering.
fig. 3a: effect of the warp knob turned cw
The warp knobs 15 affect the ripples’ uniformity during the wave’s fundamental period. In the middle position, the density of the ripple is constant (if not modulated by the ratio parameter). Turning this up bends the wave so that the density is higher at the beginning of the period and gradually decreases towards the value set with the ratio knob as it decays (fig. 3a). Turning the warp knob CCW from the middle bends the wave in the opposite direction: the density is decreased at the beginning of the period and gradually rises to the value set with ratio at the end of the decay (fig. 3b). The warp parameter can also be modulated with bipolar CV plugged into the corresponding jacks 16 .
The two miniature switches for each element, ratio track 17 and damp track 18 , allow one to choose wheth er or not the density of the ripples and the decay rate are proportional to the length of the fundamental period. In other words, they allow switching between constant spectrum of the elements (not tracking the pitch) and constant overall waveform shape (tracking the pitch)
fig. 3b: effect of the warp knob turned ccw
The shape switches 19 select between a sine-like and square-like waveform for each element. The square wave’s richer spectrum offers a more aggressive sound of that particular signal component. Sofia has several signal outputs. The main out jack 20 contains the final mix of the fundamental wave and ripple elements as defined by the mixing controls. The fundamental tone (a pure sinusoid, not affected by the saturation) is available at the fund out jack 21 . The two individual element a and b out jacks 22
Fof synthesis
The classic FOF synthesis technique proposed by X. Rodet in the 1980s efficiently synthesizes vocal-like formants in the time domain without resorting to digital filters, which, at the time, were expensive to implement. Rodet observed that the complex response of a vocal tract may be decomposed to parallel acoustic resonant filters that produce decaying sinusoidal tones (ripples) in response to each pulse of air pressure from the larynx. There is a direct relationship between the density and decay rate of the decaying sinusoid and the frequency position and spectral width of the formant.
offer the ripple waves at full amplitude, without the decay response. The decay curve is individually available for a and b at the impulse outputs 23 .
MODULATION AND SELF PATCHING
Although Sofia alone can synthesize a wide range of acoustic, woody, organic, and animal-like, as well as high, fuzzy, and bright sounds, it greatly benefits from being animated through its multiple CV inputs. Patching complex modulations, e.g., envelopes from Xaoc Devices Zadar, some audio signals, or even white noise to various parameter inputs, adds a whole new dimension to the sound.
The user is encouraged to try various self-patches from the individual outputs to inputs within and between elements a and b, which sometimes transforms Sofia into a wild and scary beast.
ACCESSORY
Our high quality Coal Mine black panels are available for all Xaoc Devices modules. Sold separately. Ask your favorite retailer. •
WARRANTY TERMS
XAOC DEVICES WARRANTS THIS PRODUCT TO BE FREE OF DEFECTS IN MATERIALS OR WORKMANSHIP AND TO CONFORM WITH THE SPECIFICATIONS AT THE TIME OF SHIPMENT FOR ONE YEAR FROM THE DATE OF PURCHASE. DURING THAT PERIOD, ANY MALFUNCTIONING OR DAMAGED UNITS WILL BE REPAIRED, SERVICED, AND CALIBRATED ON A RETURN-TO- FACTORY BASIS. THIS WARRANTY DOES NOT COVER ANY PROBLEMS RESULTING FROM DAMAGES DURING SHIPPING, INCORRECT INSTALLATION OR POWER SUPPLY, IMPROPER WORKING ENVIRONMENT, ABUSIVE TREATMENT, OR ANY OTHER OBVIOUS USER-INFLICTED FAULT.
LEGACY SUPPORT
IF SOMETHING GOES WRONG WITH A XAOC PRODUCT AFTER THE WARRANTY PERIOD IS OVER, THERE IS NO NEED TO WORRY, AS WE’RE STILL HAPPY TO HELP! THIS APPLIES TO ANY DEVICE, WHEREVER AND WHENEVER ORIGINALLY ACQUIRED. HOWEVER, IN SPECIFIC CASES, WE RESERVE THE RIGHT TO CHARGE FOR LABOR, PARTS, AND TRANSIT EXPENSES WHERE APPLICABLE.
RETURN POLICY
THE DEVICE INTENDED FOR REPAIR OR REPLACEMENT UNDER WARRANTY NEEDS TO BE SHIPPED IN THE ORIGINAL PACKAGING ONLY AND MUST INCLUDE A COMPLETED RMA FORM. XAOC DEVICES CAN NOT TAKE ANY RESPONSIBILITY FOR DAMAGES CAUSED DURING TRANSPORT. SO BEFORE SENDING US ANYTHING, PLEASE CONTACT US AT SUPPORT@XAOCDEVICES.COM. NOTE THAT ANY UNSOLICITED PARCEL WILL BE REJECTED AND RETURNED!
GENERAL INQUIRIES
FOR USER FEEDBACK SUGGESTIONS, DISTRIBUTION TERMS, AND JOB POSITIONS, FEEL FREE TO CONTACT XAOC DEVICES AT INFO@XAOCDEVICES.COM. PLEASE VISIT XAOCDEVICES.COM FOR INFORMATION ABOUT THE CURRENT PRODUCT LINE, USER MANUALS, FIRMWARE UPDATES, TUTORIALS, AND MERCHANDISE.
MAIN FEATURES
Analog VCO with complex waveforms
Extended FOF synthesis
3 frequency control inputs
8 parameter control inputs
6 signal outputs
TECHNICAL DETAILS
Eurorack synth compatible
24hp, 30mm deep
Current draw: +90mA/-80mA
Reverse power protection
ALL RIGHTS RESERVED. CONTENT COPYRIGHT ©2022 XAOC DEVICES. COPYING, DISTRIBUTION OR ANY COMMERCIAL USE IN ANY WAY IS STRICTLY PROHIBITED AND REQUIRES THE WRITTEN PERMISSION BY XAOC DEVICES. SPECIFICATIONS ARE SUBJECT TO CHANGE WITHOUT PRIOR NOTICE. EDITING BY BRYAN NOLL.
Documents / Resources
| XAOC
1955 Transcendent Waveform Analogue
Oscillator
[pdf] Instruction Manual
1955, 1955 Transcendent Waveform Analogue Oscillator, Transcendent Waveform
Analogue Oscillator, Waveform Analogue Oscillator, Analogue Oscillator,
Oscillator
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References
Read User Manual Online (PDF format)
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