A Percussive Sound Synthetizer Based on Physical and Perceptual Attributes

       

Authors: Aramaki M., Kronland-Martinet R., Voinier T., Ystad S.
Publication Date: June 2006
Journal: Computer Music Journal (vol. 30(2), pp. 32-41, 2006)

Tags:


The sounds below have been synthetized in real time, using the MAX/MSP instrument described in the paper.

Simulation of the material contribution

By simply filtering a white noise, sounds corresponding to impacts on various materials can be designed. Depending on the evolution speed of the time-varying filter, the sound seems either “metallic” or “muffled”:

Effect of modal contributions

From a mechanical point of view, modes are strongly dependant on the geometry  of the structure. From a signal point of view, modes correspond to mono-component  contributions. By simply adding one sinusoidal component to the strongly  damped noise (sound example 1), one can either simulate large or small sounding  woods:

Two ways of addying modal contributions

As discussed in the paper, modal contributions can be obtained in two  main ways. The first one consists in summing up deterministic components (sinusoidal waves) whereas the second uses narrow band-pass filtered versions of the entrance noise. As a result, the second approach leads to a better fusion between the noisy and the modal parts of the sound.
The synthesized sounds below are obtained using five modes.

Some examples of impacted sounds generated by the model

Simulation of the dynamic of the impact

The strength of the impact is correlated to the amount of energy given to  the sounding structure. As a consequence, the stronger the impact, the richer  the sound. These dynamical characteristics are simulated by controling a low  pass filter bandwidth by the impact force.

A crucial aspect of the mapping – the tuning

The pitch of complex sounds still is an open issue. As an approach, we proposed  to tune the impacted sounds by considering the modal components as a cluster  of notes. Sounds can then be tuned by associating musical chords to sounds. These chords are defined by the tonic notes, the harmonic structures (major, minor, 7th, 9th, diminished, …) and their inversions.

Control of the material

Morphing effects simulating continuous transitions between two materials can be obtained by interpolating the synthesis parameters. These sound examples are currently used in neurophysiological experiments to study the categorization process of impacted materials