The use of fixed plates as the Baschet brothers used them is unique, as far as we know. Flat rectangular plates or bars have been used in many locations and cultures, typically mounted in such a way that they are freely suspended at their nodal points. This allows their fundamental idiophonic mode of vibration to dominate, as can be heard with xylophones, marimbas, glockenspiels, vibraphones, gamelan gangsas, etc.56 The Baschet also made use of freely-suspended plates in many pieces, usually coupled to resonating pipes, demonstrating their familiarity with with this common paradigm of freely suspended plates as well as their unique implementation of fixed (not freely suspended) plates.
We have chosen to include the fixed plates of the Baschets as part of the odontophone mounting settings because they share some of their complex behaviour. This setting is diametrically opposed to the one used in freely-suspended plates. Here the plates are clamped, either through-bolted in their center or in any other section of their length, and their natural tension and vibrational modes are completely modified. While the usual freely-suspended plate vibrates with an antinodal region in its center, when a plate is tightly bolted in its center, a nodal point is imposed there, creating a forced tension that imposes a new wavelength to the freely-vibrating end of the plate. This fixed region is also where the vibrations can be transmitted to a coupled radiator. In other words, this system converts freely vibrating plates into a tongue (or a tooth), since they are firmly clamped, and the vibrations will be transmitted to any other solid in contact with that clamping bolt. Even when those plates feature wider surfaces and are more likely to radiate vibration to the air, some of the vibrations will be immediately transferred to a gum or to a radiator, adding natural resonant formants and frequency responses and radiating the lower frequencies that otherwise would not be radiated.
Also, when several plates are bolted together, complex systems are created. Again, as with our big comb-like rod percussion instruments, several interactions may occur, none of which would occur if the same plates were freely suspended. The most relevant issue here is that the sound becomes completely different when the plates are clamped: the resulting pitch, as well as timbral envelope, of the same plate changes, depending on whether it is suspended freely or tightly clamped. As we have said, the coupled radiators also add their own colours, so, when considered as a compound system of oscillation, there is a certain modularity regarding sound design in fixed plates that we do not find in free suspended plates, offering a wider range of new combinations to explore. The Baschet used balloons, cardboard, and metal cones as radiators for fixed plates, each one offering its own timbral qualities.
Bali, circa 1965
Oscillators: 11 iron plates, fixed symmetrically on a threaded rod.
Radiation: Two stainless steel cones that not only radiate the sound originating in the plates but also add their own bright resonance and reverberation, creating a somewhat subaquatic sound.
Gamut: Xentonal, approximately (A, C#, D#, F#, G#, B, D, F#, A, C#, F#) but not tuned to any particular temperament. We can see there are pitches that appear in two different octaves, so there has been a careful process of tuning, by adjusting different plates, with the intention to create a cohesive gamut.