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in nomine tenebris

12/3/2015

The opening of the cello part for in nomine tenebris

The score for in nomine tenebris was created from a sonogram of Giacinto Scelci's organ work In Nomine Lucis that was stretched, warped and distorted in the visual domain using Photoshop and Illustrator. Parts for the five instruments were created by colouring and annotating features of the sonogram (the opening of the cello part is to the left). This allows to performers to acoustically recreate minute and continuous changes in pitch, dynamic and timbre by following the height, thickness, shape and shade of the image. The players perform the work from scrolling scores synchronised in the Decibel Scoreplayer.

in nomine tenebris makes use of the new OSC communication features of the Scoreplayer. The addition of OSC communication allows for the coordination of functions that were previously independently conducted by the iPad and computer, most crucially audio processing. The current implementation reports the score position via OSC as a number between 0 and 1 (where 0 is the first frame of the score and 1 is the last) in the format /Control/Tick 0.445. The amount of time elapsed can therefore be calculated by multiplying this number by the duration of the score. In this way audio processing can be cued by the position of the score itself.
Conversely, the score can be repositioned by sending a /Control/Seek 0.5 message to the iPad (see below). Other currently implemented control commands are /Control/Play (start score), /Control/Reset (stop and reset score) and /Control/SetDuration (change the duration of the work). Additional commands will be added for the requirements of individual scores.

in nomine tenebris uses this function to align the scrolling score (based on a sonoogram) with a recording its a re-sonification, by using the position of the audio file (reported by snapshot~) to control the position of the score. The contours of four of the instrumental parts are used to determine the spatialization of the audio over 8 speakers (see below)

The audio processing patch for in nomine tenebris

Instrumental part contours (Left) used to control spatialisation of the audio image (Right).

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The approach to Score Generation in Semantics of Redaction

12/3/2015

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The notation for SoR (Image left) is principally created by using accents detected in a speech recording in real-time to generate graphical symbols of varying vertical position, size and colour, determined by the frequency, amplitude and timbre of the recording at the accent point.

Analysis of the recording is derived from Tristan Jehan’s analyzer~ object, using attack, frequency, amplitude, brightness and noisiness data. The flow of analysis data is captured at the point of each detected attack (See Figure 2). By default the values defining an attack are an increase in the incoming signal of +10db in a period less than 100ms, however the performer may alter these values to achieve a better score/visualisation result.

The opening section of The Semantics of Redaction [2014].

The flow of analysis data is captured at the point of each detected attack.

The data is mapped in the following manner:
Frequency: Vertical height and notehead colour hue

Amplitude: Notehead size
Brightness: Notehead colour saturation
Noisiness: Notehead colour luminance

The data is drawn to MaxMSP’s jit.lcd object using the standard paintrect command (see Figure 3). A stem is also drawn on the left side of the notehead above a central “beam”. The left side stem is used regardless of whether the notehead is above or below the beam as an aid to visualising the precise onset of the accent and therefore performer’s note execution.

Because of the variation of the acoustic characteristics of potential recordings and performer preferences, an analysis window allows the performer to scale incoming data. Scaling changes may be necessary because of variations in the average frequency of the speaking voice or ambient noise in the recording. From the performer’s perspective the attack rate and sensitivity values create changes in the density number of note events in the score.

The analysis window provides the performer with “peak”, “trough” and “mean” values for each of the analysis parameters from the recording, as well as a graphical display showing the most recent 100 values for each parameter. A swatch graphically displays the variations in notehead colours. A preset object allows the performer to save the chosen scalings for each new recording.

Data is drawn to MaxMSP’s jit.lcd object using the standard paintrect command.

Analysis window (detail) performer-variable scaling values.

Although it would be possible to automate the scaling process, allowing the performer to set the values provides a means to individualise the score that is generated. For example to achieve variations in the number of noteheads that fall in different “registers”.
Unlike Lyrebird, which has a range of colour interpolations and generates a spectrogram-like score, only five hues (Yellow, Orange, Red, Green and Blue) are used in SoR (although there is continuous variation in the saturation and luminance of each colour). This approach was taken to achieve a clear differentiation between five registers in the score which are conceived as instrument groups by the percussionist: for example ranging from yellow (high-pitched instruments) to blue (low-pitched instruments). The notehead size is intended to correlate to the performer’s dynamic range.

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in nomine tenebris

The approach to Score Generation in Semantics of Redaction

lindsay vickery

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