by Julian Villegas (julovi \ at \ yahoo \. com)
Although the problem of maximizing consonance in tonal music has been addressed before, every solution reflecting the technological advances of its epoch, and considering that current theories to explain this psychoacoustical phenomenon are generally satisfactory, there are still vast unexplored aspects of this area, since even most recent solutions lack adequate mechanisms to apply such techniques in realtime scenarios. In general, the most advanced achievements in this field are based on the MIDI protocol for controlling the pitch of simultaneous notes, inheriting the protocol limitations in terms of dependency on the quality of the synthesizer for satisfactory results, scalability, accuracy, veracity, etc. Besides that, timbres are generally known a priori for these techniques, so their application to unknown timbres requires digitization and analysis of sound samples, making such techniques unsuitable for realtime situations. This thesis summarizes the main theories about consonance and its relation to musical scales, reviews several previous solutions as well as the state of the art, proposes an alternative model to adaptively adjust consonance in a polyphonic scenario based on the tonotopic dissonance paradigm (presented by Plomp and Levelt, having been previously developed by Sethares), and presents a prototype of this model that aims to surmount the difficulties of prior solutions by performing realtime analysis and pitch adjustment programmed in Pure Data, a data flow DSP environment for realtime audio applications. The results are analyzed to determine the efficacy and efficiency of the proposed solution.
The prototype (a ZIP file containing the libraries and PD patches) can be downloaded here.
The PDF document can be downloaded here.
Porting the application to Max/MSP and other platforms (currently only works in Windows boxes)