Introduction to Odontophones
In the Baschet work a variety of devices are used to produce sound: strings, suspended plates, wind instruments, bells, etc. Of these sound objects, the most deeply explored and developed acoustical family is that of the clamped oscillators, primarily steel rods; there are hundreds of instruments and sound sculptures based on the use of clamped rods as oscillators.21 François Baschet had a particular sense of humor and always explained that since the rods must be tightly fastened to a collecting element to vibrate properly, they could be compared to the teeth in our mouth since they need to be securely attached in order to serve their purpose. If a tooth, or a rod, is secured loosely, it does not work well. Thus, the Baschets always referred to the element to which the rods are clamped as “the gum” (gencive in French). The gum is the element that accumulates the vibrations of the oscillators.
The family of Baschet sound objects based on the use of clamped oscillators is so extensive that it deserves its own name and should be characterized and understood of itself, with the understanding that naming things helps in establishing an identity in the eyes and consideration of others. Therefore, we propose a term that aligns with François Baschet’s humorous terminology. If all of these structures have gums, upon which the oscillators are clamped, and if those clamped elements are like teeth in their gums, why not call them odontophones, with the Greek prefix «οδους» (odous) or «οδοντος» (odontos), meaning tooth and teeth? Odontophones are therefore teeth that produce sounds.22
We characterize odontophones as sound devices with elements and features addressed below.
Oscillators – typically, rigid elements in the shape of rods, bars, or plates, clamped to a bridge or heavier sound accumulator (gum) – that are most commonly activated by percussion, plucking, or friction, generally transfer the sound to the transmission medium through coupled radiators, solid elements offering a sufficient radiating surface (wooden soundboards, cardboard and metal cones, stretched membranes, etc.) that also filter and colour the vibrations depending on their own frequency responses.23 The sonic gamuts, tonally and timbrally, created through these oscillating-radiating systems are defined and articulated by the oscillators’ different sizes and tensions, and the solid connection between these elements makes each of these elements a potential resonator for and with the others.24
In this exposition we address the complexities of clamped rods and the resultant atypical series of nonharmonic overtones – particularly the impact of spectral content on the perceived pitch, multiphonic, and timbral qualities – because we find them interesting in themselves, and we believe this approach can help us better understand and appreciate other musical instruments, sound sculptures, toys, and sound objects. The odd, counterintuitive, and often challenging behaviour of clamped rods allowed the Baschet brothers to search for, and discover, new sound qualities. In many senses the counterintuitive vibrational patterns of clamped rods challenge the builder and the player, both in terms of sonic potential as well as visual configuration.
For example: two rods can differ in length yet vibrate at the same pitch with a different timbre, depending on the specific batch of material and the variations in intrinsic elasticity of the material. Another counterintuitive fact: given two clamped rods of the same length, one thicker than the other, the thinner rod, when activated with a given force, will emit a slower fundamental oscillation because it is less rigid (and the resulting displacement is wider and slower). In the thicker rod the fundamental oscillation will be faster,when activated with an equivalent force, because it is more rigid (the internal tension is higher). Or, even more counterintuitive: a shorter rod can emit a lower pitch than a longer one. The examples section of this exposition offers several instances of this phenomenon: Kawamiphone, Katsuraphone, SAD, and Brontosaur.
The inharmonic behaviours of clamped rods are not esoteric – physics can explain them – but they defy common expectations that are based upon the prior experience most people have with strings and air columns in musical instruments. Exploring and understanding this inharmonic behaviour is interesting in its own right and can promote more empirical approaches to learning as an alternative or complement to purely theoretical approaches. The mathematics that can describe and predict these complex behaviours is quite likely too advanced for most of us, but we can develop a general comprehension of the complex modes of vibration through observation of multiple cases.25 Direct manipulation of the system elements (experimentation) can facilitate an even deeper understanding. As an introduction to the possibilities, we have provided audio files, images, videos, and spectrograms to help curious readers understand this fascinating subject. Finally, we encourage everyone to experiment with building their own odontophones.