5. 6. 2021

English Version | To the sound of sound

by Sara Andrade


Or better yet, the vibe. Because the power of the vibration of sound waves in natural elements, like in sand or water, might provoke geometric patterns of such symmetry that the expression “good vibes only” gains a whole new dimension.

We’re not spoiling anything to anyone by saying that sound and vibration are two interconnected concepts – after all, we have all that to run behind that mini-speaker that insisted on getting away when its volume was on max, or that glass of water someone left near the (loud) sound system, that nearly shattered. But perhaps you never realized how those vibrations are not completely random. Putting together the right frequency and the right element – such as sand – is a geometry match that will make any mandala jealous. The effect is not as hypnotizing when described as it is when witnessed with one’s own eyes, but that will not stop this article from giving it its best shot. First of all, it’s important to understand what sound is, to then understand that capacity of influencing the elements. Put very simply, sound is the propagation of a mechanic compression front or mechanic wave. It results from the vibration that is transmitted through that propagation from a source of sound to a detector or a sound receptor and for that to happen, it is necessary that between the source and the detector/ receptor there are material conductors (solids, liquids or air) so it can be perceived – that is why sound doesn’t travel in the void. The vibration of one sound source causes a wave, and that undulatory movement will propagate in every direction through invisible waves: sound or acoustic waves. That sequence of sound waves, or displacement waves, density and pression, that travel through compressible means, describe what sound actually is.

“We might understand what sound is by seeing what happens when a rock falls into a water surface and generates waves that travel through that surface”, Rui Dilão starts to explain, a Professor of Physics Mathematics and Dynamic Systems in the Instituto Superior Técnico da Universidade Técnica of Lisbon. “When we talk, opening and closing our mouth in a continuous way, we cause alterations in the air density around us producing a sound wave. Our eardrums are very thin vibrating membranes that sense these variations in the air density and transmit that information to our brain”, he explains, alerting, in the simplest and comprehensible way possible, to this idea of traveling between the source and the receptor, adding that “the propagation of sound is related to the atomic nature of matter and with the shocks between molecules of a gas or fluid.” Speaking of the influence of sound in elements, “fire, water and land are fluids composed by mobile particles, thus the shocks of air molecules with those of these fluids might induce the propagation of the sound wave in their interior. As underwater the sound waves are quickly suppressed, to communicate through water or other fluids, sound waves have to be intense enough to do so. In that case, phenomena like the effect of shocks in the fluid’s molecules can be observed. The sound waves generated by earthquakes are due to extremely intense movements occurring inside Earth”, he exemplifies. And concludes: “For example, the sonoluminescence is the production of light through sound.  In that effect, the created sound wave forces a gas bubble inside a fluid to expand and contract, emitting a ray of light.”

Why are we contextualizing this? Because it is necessary to understand that this duality of sound as an immaterial reality, but that might as well be tangible, gains shape (beautiful shapes, we might add) if we comprehend the cymatics, meaning, the study of sound waves and its association with the physical patterns produced by their interaction with a certain environment. It is a study that comes from the same principle that our assumption about the love affair between sound and vibrations. “Sound kickstarts a reaction everywhere! I would say mostly in our neuro-physiological system”, Simão Costa confirms, the musician, composer and pianist, who was been exploring the physical properties of sound, assuming it as a physical phenomenon that doesn’t look “all that tangible, but it isn’t. For example, if we go to a party with a DJ and the bass tones are turned off, no one will dance, and everyone will be ‘uncomfortable’. There you go, it is more tangible than what it may seem at a first glance.” And he continues: in the case of “sand, if it is placed on a surface or membrane, it provokes geometric patterns that correspond to the geography of the vibration of that object; fire can be very influenced because if the air is vibrating, it might alter the way oxygen is made available during the combustion process, allowing for the observation of the waves of air compression; in water it is etc. – it is delightful to observe sound influence that element. We ‘see’ the air vibrating with our ears, and we do that in a very detailed manner, the verbal communication between human beings is an excellent example of that. The way sound unravels is constantly feeding us information about our surroundings, allowing us to ‘see’ in every direction”, he states. Simão was the artistic director of the exhibition c-Vib (Cymatics_Vibrating Interactive Boards), a patent of the Pavilhão do Conhecimento between the fifth of February and the third of April, but the sound and musical culture of the artist remain exposed – and with free access – in the atrium of the Pavilhão do Conhecimento. The project “c_Vib is made up of four sound sculptures with a 180mx180m base, where wood and speakerphones playing [Simão’s] music intertwines, and in which we can ‘listen with our ears’ but also with our tact, whenever we sit, lean or lay on those sculptures. They are also ‘characters’ and the scenery for a dance spectacle led by the dancer and choreographer Yola Pinto, with whom I share the art direction of this project. Works of art are useless, there are not at anyone’s service, they just are. That’s why it is difficult (impossible) to talk about them in a concrete way. Experimenting and/ or contemplating a work of art, is the concrete device, hence no matter how much you write or talk about the work… One must take one’s body and go along with it wherever art is.” The musician shares an invite to get to know the work, which is, in fact, yet another landmark in the musical path that is made in a very unrestrained manner from the procedures of composition, given he has always tried to overcome the comfort zone of his métier. Indeed, his most recent solo record, Beat With Out Byte(un)learning Machine, is an example of precisely that, exploring a very particular musical characteristic: the pulse. “Cycles, beats, repetitions in homeostasis; a process of regulation though which an organism is capable of upkeeping its balance, characterized by its stability and also unpredictability”, he refers, adding that “all sounds are acoustic, produced from piano cords and magnets placed over them, captured from the vibrating air particles.” We confirm that we are, in fact, talking to the right person about sound and its influence over the elements. Even more so because, he confesses, “to add to my condition as a pianist, a more connected condition to artistic creation was a symptom. […] Through that route, I embraced the condition of composer, ‘inventor’ of sounds and instruments. Firstly, I had to transform myself from an uninformed person to an informatic programmer, the computer was a tool that was just asking for it… After starting to build instruments ‘inside the computer’ I started finding it interesting that those ideas were becoming more tangible. Knowing how to embrace older technologies and conciliating those with the invention of new connections and discovering the right dosage of these relations is an exercise that feeds me well”, he confesses. And that gave him the necessary arsenal to not only affirm himself in this musical field but also to talk to us about this vibration game: “In practical terms, ‘the vibration game’ is a good definition for music! To some, it might not be the most romantic of definitions, but to me, it is precisely that. As in every other game, there are rules that are very restrict, while others leave a bit more of a margin for action. If the game happens and there is enthusiasm by those playing, then things should be going well”, he theorizes.

This vibration game is much more than just science alone – it is art. An affirmation that also doesn’t come as a spoiler, something we have corroborated in previous paragraphs. If around this point in your reading you have resisted the temptation of going searching for videos that demonstrate this influence of sound in elements such as sand, water, fire, we might go forward with our testimony that it is an experience worthy of a lack of words – which is curious, because all of this revolves around producing sounds. But if you’ve made it this far, hold on just a little longer – we have better keywords for the SEO. The influence of sound waves in natural elements is not only scientific, it is a show: “Since sound waves are carried by the materials’ molecules, any material that is sufficiently elastic can be influenced.” We go back to the Physics Mathematics teacher to hear the explanation of those who can do it best. “The simplest one to influence is sand. By generating vibrations on a sand-covered surface, stable geometric patterns will appear on the surface, called Chladni patterns. If the vibrations were had been originated by voice, for example, by reading a poem by Camões or Pessoa, the Chladni patterns will be significantly different, being able to produce a singular aesthetic impression. In one of the interactive modules of the permanent exhibition of the Pavilhão do Conhecimento – Centro Ciência Viva, Chladni patterns can be generated in a rather simple manner”, Rui Dilão challenges, he who is also involved in the C_Vib exhibition. Why Chladni patterns? Ernst Chladni (1756-1827) was a musician and physicist from Germany who conducted vast research on vibrating plaques and the speed of sound in different gas bodies, and that is why he is often quoted as “the father of acoustics”. One of his major works tackles, within these geometric figures that result from the vibration of sound, a technique that shows how different forms of vibration might unravel different shapes or patterns. By resounding, a certain plaque or membrane is divided into regions that vibrate in opposite directions, outlined by lines where no vibration occurs (nodal lines, meaning, lines without movement). Chladni repeated, in fact, the experiences of Robert Hooke who, in 1680, had observed the nodal patterns associated with the vibration of glass plaques. Hooke swept a violin arch across the edge of a plate with flour on it and saw the nodal patterns resurge. In the case of the Chladni patterns, in that same plaque, the alteration of the position of the vibration point reveals different figures that correspond to different types of vibration of that plaque. Patterns are also susceptible to change with the alteration of other parameters, such as the shape of the plaque, its thickness, size… “The different patterns are generated essentially through frequency (tone and frequency are two different ways of referring to the same characteristic). In the case of voice, frequency is variable and therefore, the sand patterns vary depending on the phrases. On the other hand, by increasing the intensity of the sound can generate complex patterns, many of them rather chaotic”, Dilão clarifies. “Other geometric patterns are related with the capacity of a gas or liquid to support very intense disturbances, generating ‘shock waves’ triangularly shaped. When we see a duck swimming peacefully in a lake, concentric waves appear around its body. But when a duck swims in rapid movements, those waves transform into a perfectly traceable triangular trail. The speed that determines this is the speed of sound in water.” One piece of evidence that everything influences the shape is this symmetric result, only possible through the symmetry of the base. Usually, symmetric places result in symmetric patterns, because the vibration zones and the nodal zones, meaning, without vibration, will also be symmetrical. When there is an asymmetry in the plaque, usually the result will also be a little more chaotic. That is why the shapes of Chladni are practically applied in the verification of the quality of an instrument, since the object obviously influences the acoustics and its sound – if the thickness of, for example, a violin’s wood, its shape or disposition, are symmetric, then those patterns of Chladni will also be symmetric. Interesting, right? After all, this text had everything to make itself heard, although the visual support might fall short. Even so, practicalities aside, to see the formation of these prints is somewhat of a work of art. Art, that element that is everywhere and that finds nothing but another corroborative argument here.

Yes, it is a cliché to say that art is everywhere. But one that is also true, if this article has taught us anything. One of its manifestations, connected to this theme of sound and its relation to materials, is the collection of pieces, installations and spectacles Dança de Materiais Inertes by the musician Simão Costa in partnership with the choreographer Marta Cerqueira: “In this project, there is a very specific exploration of the kinetic potential of sound”, Simão argues. “Sound is used to make particles or objects dance. Marta and I choreograph objects in contexts where sound is the motor that brings them to life. It puts things in motion. Many times (many, many times), materials, even if inert, seem to come to life just because they are being mobilized by sound. This makes us think about the limits of biology and geology, of what is alive and what’s not; with it, we intend on analyzing some of the ‘nervous twitches’ of a certain congenital anthropocentrism characteristic of human beings and provoke some sort of relief of those tics regarding other ways of dealing with our surroundings, whether they are alive or dead, human, animal or vegetable.” It would be valid, very valid to establish a parallelism between the vibration of sound and human beings: “Beyond our eardrums, our skin is elastic, it absorbs sound waves and transmits them to the brain through nervous receptors. That is why a deaf person can dance. Sound communication is one of the most important means of communication amongst human beings”, Rui Dilão corroborates. All of this is true and very pretty, but what sounds better in all of it is being able to start saying “the noise of lights” and being able to sustain an argument when someone laughs at the expression. Besides how the patterns of Chladni and their demonstration are a great conversational ice-breaker when silence kicks in.

Translated from the original, as part of Vogue Portugal's Music Issue, published in june 2021.