Dynamics and waveforms
Excerpt from Helikopter-Streichquartett, Karlheinz Stockhausen. © Stockhausen-Stiftung für Musik, Kürten.
Image used with permission.
Dynamics is one of the key features that determine our perception of sound. The amount of energy experienced as "loudness" or "quietness" plays an important role in descriptions of passages or analyses of music pieces.
Unavoidably this concept is associated with the idea of being “small" or “large": the louder a section is, the "bigger" we conceive it to be. Passages from soft to loud or vice verca evoke impressions of movement going upwards or downwards.1 In this regard, waveforms or waveform-like shapes become convenient tools for visual representations: with their vertical axis depicting changes in air pressure (displacement of air molecules due to sound phenomena), they can be used as visual surrogates for loudness. Their vertical axis represents amplitude and the peaks in changes of air pressure are useful mediums in distinguishing between different levels of dynamics.2
Horizontally, the varying patterns of waveforms are mainly related to timbral characteristics and harmonics. However, it is not easy to discern value differences directly, or derive conclusions on the time axis: "while waveforms provide exactness in the realms of amplitude and duration through visual peaks and valleys, the vital categories of pitch and harmonic content become inaccessible.”3
Although pitch and harmony is not the topic of discussion here, it is important to recognize waveforms as visual assets, which enable sound perception in spatial and topographical terms.
1 Characteristic is the depiction of crescendo (soft—>loud) and diminuendo (loud—>soft) wih the symbols < and > respectively.
2 Loudness and amplitude are used interchangeably, although it should be noticed that loudness is a psychoacoustical phenomenon, based on human perception, whereas amplitude is the displacement of a wave from its mean value (displacement of air molecules).
3 Daniel Siepmann, "Digital Audio Workstations: Notation and Engagement Reconsidered," NewMusicBox, December 11, 2013, https://nmbx.newmusicusa.org/digital-audio-workstations-notation-and-engagement-reconsidered/.
Visual precedents and sketches
1. Excerpt from Dextral Shift, © Benjamin Bacon | Image used with permission
2. Extra music notation: Debussy's Arabesque No. 1, © Kanny Yeung | Image used with permission
3. This is how it happened, © Dragana Crnjak | Image used with permission
4. Image from Formulation: Articulation (1972), Josef Albers | No copyright owner was identified
5. Dynamics. Personal sketch | License: CC BY-SA 4.0
6. Labeling system (on Björk's Post), © Joshua Distler | Image used with permission
