A performance exercise to create awareness of the potentialities of very low sound levels to create a silence canvas, an acoustic space for a listening experience.
5.1.1 Tags
Loudness, dynamics, silence.
5.1.2 Goal
This task is intended to enhance the listening in a collective playing situation by forcing both overall and individual sound levels to be as low as possible. Perform- ing at the softest possible volume enables the listener-performer to appreciate and focus on the details of each musician’s performance. The detailed listening will reveal aspects of the sound of the group as a whole and will stimulate forbearance in each performer, simultaneously allowing the creation of sonic and performa- tive spaces where music and sounds can live comfortably without struggling to be heard. A consequence of this task should be a deeper understanding of the dynamic control and possibilities of the instruments; each instrument should be adjusted to be able to play at the low energy end of the sound level. If this is not possible, the instrument is not suitable for the task.
5.1 The Canvas – Silence 109
5.1.3 Description
All the musicians start an improvisation playing pianissimo simultaneously; when one of the musicians notices that he or she is playing louder than somebody else, he or she must decrease the volume below the other person’s level and continue performing while permanently adjusting the level to avoid playing louder than anyone else in the group.
Obviously, the music should gravitate towards silence since each musician is trying to play under the volume of the others. However, total silence is not the goal. Instead, a subtle crystal pianissimo like a Silence Canvas should emerge from the performance.
5.1.4 Variations
The silence canvas concept can be explored by imposing restrictions on the sonic material used. For example, continuous sounds, granular textures, bursts of at- tacks, inharmonic sounds, noises or pure tones will produce completely different results. Experimenting with the sonic material and intensifying the listening of the quiet volume and soft sound levels may suggest turning off the amplifiers and continuing with acoustic and mechanical sources or even taking the sources away and reducing the experiment to the performer’s body sounds, how far could we go? listening to each other’s blinking eyes? Does the listening focus change if the amplifiers are switched on again?
Another area of possible exploration consists of reducing the focus of attention on the whole group (i.e. trying to never play louder than anybody else) to fixing the attention on a single member of the band (i.e. never playing louder than x or y performer). In this manner, it is possible to investigate the subtle shift in perception that occurs when moving from a listening experience of the band as a whole to a more discriminating and selective listening experience.
Exploring the location of the musicians and the sound sources in the room will introduce new challenges and aspects to experiment. While proximity may help to build in the subtleties of the task, spreading the sound sources in the room and keeping the individual and overall volume low will be more demanding and will require extra concentration. Another step could be to invite some persons to be the public, which will inevitably increase the noise floor and could potentially make it more difficult to listen to the other members of the band.
5.1.5 Discussion
After the task proposed in this chapter, some concepts can be studied and dis- cussed. Let us start with Signal-to-noise Ratio (SNR). SNR is defined as “the logarithmic power ratio of the signal and noise and typically expressed in dB.”1
SNR informs us about the amount of noise introduced or presented in a system. Every electronic instrument has a noise level; it can range from very noisy devices such as amplifiers built around vacuum tubes to very silent high fidelity systems. That system’s noise can be revealed by turning up the gain while injecting no or very little input signal. Beyond the electronics, it is also possible to experi- ence the noise floor of a room by focusing on it. Even further, as the exercise suggests, focusing on our inner being, guiding our inner listening, may also help us to learn about the “system noise” present in our body and mind. In the idea of the silence canvas, I propose to explore the proportion of audible signals just above the inherent noise of electronic instruments.
Another concept that naturally arises from this discussion is Dynamic Range (DR or DNR), which is another ratio measured in decibels, this time between the largest and smallest values of a variable quantity, such as sound.2 In mu-
sical terms, this is a very well-known and studied parameter. Musicians master a large dynamic range from the very subtle pianissimo to the impetuous for- tissimo. The dynamic range has been pushed in both directions (quietness and loudness), making popular standard notations such as “pppp” or “pppppp” and “ffff” or “fffff” (pianissississimo and fortissississimo). In electroacoustic music, the dynamic range is not limited by the physical capacities of the musician but by the dynamic qualities of the system and by sharp, critical and sensitive listening. Adjusting the levels and controlling the dynamics while performing electronic instruments may feel as simple as turning a knob or a fader. However, a well- balanced mix and subtle volume management require focused listening and the acquaintance with the sound qualities of amplifiers, speakers, mixers, converters, microphones and all parts of the electroacoustic chain.
The Dynamic Range for human hearing is very large and depends on different par- ticular and subject-dependent conditions such as health, listening environment, motivation, nature and features of the stimulus: semantic, lexical, syntactic, and emotional.3 In a broad sense, for the purpose of establishing a loose reference,
it can be said the Human Dynamic Range extends from the hearing threshold (around -9dB SPL at 3 kHz) up to the pain threshold (from 120–140dB SPL , without protection), Approximately 100dB range (frequency dependent) in nor-
1 “ADC and DAC Glossary – Tutorial – Maxim.” Accessed August 15, 2018. https:
//www.maximintegrated.com/en/app-notes/index.mvp/id/641.
2 Ibid.
3 Gelfand, Stanley A. Hearing: An Introduction to Psychological and Physiological
5.1 The Canvas – Silence 111
mal conditions.4One can appreciate how the development of technology through-
out history has expanded the useful Dynamic Range in electroacoustic equipment. For example, magnetic tapes from the 1950s had a useful range of 60dB. Today, 24-bit digital audio calculates to a 144 dB dynamic range, and computers process audio with a 64-bit floating point resolution that has increased that range consid- erably. These values mean that electronic instruments can dynamically cover the full range of human hearing; as a consequence, the study of the Dynamic Range in electronic instruments should focus on crafting the subtleties and mastering critical listening instead of trying to expand the limits. That is the purpose of the task introduced in this subsection: to create a listening attitude towards the details while demanding full concentration and decision-making on the handling of individual and overall volumes.
This chapter can be seen as an invitation for performers to experiment with the concepts of Just Noticeable Difference in sound level and thresholds of percep- tion. “The Difference Threshold (or ‘Just Noticeable Difference’) is the minimum amount by which stimulus intensity must be changed in order to produce a no- ticeable variation in sensory experience.”5 As John Sloboda remarked, factors
such as the focus of attention in a musical context can challenge the relevance of experiments attempting to define Just Noticeable Difference values of general validity.6 Therefore, experimental and empirical research should eventually pro-
duce practical, useful and applicable results in the context of sound performance. Other aspects of the Dynamic Range will be explored and discussed in section 6.1
5.1.6 Implementations
A fantastic device to work within the context of this chapter is an analog compara- tor. A comparator can be used as a level crossing detector, allowing for triggering and gating events on the basis of instantaneous analysis of signal levels. I suggest to either build one or integrate one in a synthesizer patch.
An analog comparator is basically an amplifier without feedback and thus has very high gain.[. . . ]Typically an analog comparator compares voltage levels on two inputs and gives digital output based on the comparison.
4 Sherlock, LaGuinn P., and Craig Formby. “Estimates of Loudness, Loudness Discom-
fort, and the Auditory Dynamic Range: Normative Estimates, Comparison of Proce- dures, and Test-Retest Reliability.” Journal of the American Academy of Audiology 16, no. 2 (2005): 85–100.
5 “Weber’s Law of Just Noticeable Difference.” Accessed August 15, 2018.
http://apps.usd.edu/coglab/WebersLaw.html.
6 Sloboda, John A. The Musical Mind: The Cognitive Psychology of Music. Oxford
When the voltage on the positive input (Vin0) is greater than the voltage on the negative input (Vin1) then the output voltage (VOUT) is saturated to its positive supply (+VSUPPLY), otherwise the output is saturated to is negative supply (-VSUPPLY). In microcontrollers, since there is no negative supply voltage, GND (ground level) is taken as –VSUPPLY and VCC level is taken as +VSUPPLY.7
† Build or program an instrument using the ideas of Noise Gate and sound compression according to the concepts presented in this chapter. Eventually, mapping thresholds, limits and ratios to exposed controls or automatic trans- formations to produce or process sounds. Imagine an instrument that changes its behavior according to the input levels. Often a noise Gate is used to auto- matically close a line or a microphone when the signal is below a certain level, but how could this idea be reversed and used as the basis of an instrument? † Write a program that analyzes the amplitude of an incoming signal and ap- plies a subtraction to this value of 1, 2 or 3 dB and a delay of 1 or 2 sec. Then, map this new value to control the amplitude of a noise generator, synthesizer or sample player. Explore the responsiveness and the accuracy of the software while always aiming to play below the output level of the program.
† Write a program that plays two different sounds that react to the level of an incoming signal. The two sounds are mapped to the upper or lower level of a hand-adjusted limit. For example, on a scale of 0-1, determine the boundaries of 0.2 and 0.8. Playing sounds under 0.2 will play a different sound than sound at 0.9. If the goal is to keep the program silent, explore reducing the boundaries and moving towards the lower end. How much compression can you handle on your dynamic range? Are 0.01 and 0.1 achievable limits?
7 “AN_42473 AT11480: Analog Comparator Application Examples | Application Notes
| Microchip Technology Inc.” Accessed August 15, 2018.