Physically inspired signal model for harmonium sound synthesis
The hand harmonium is arguably the most popular instrument for vocal accompaniment in Hindustani music today. However, it lacks microtonality and the ability to produce controlled pitch glides, which are both important in Hindustani music. A harmonium sound synthesis model with a source-filter structure was previously presented by the authors in which the harmonium reed sound is synthesized using a physical model and the effect of the wooden enclosure is applied by a filter estimated from a recorded note. In this paper, we propose a simplified and perceptually informed signal model capable of real time synthesis with timbre control. In the signal model, the source is constructed as a band-limited waveform matching the spectral characteristics of the source signal in the physical model. Simplifications are suggested to parametrize the filter on the basis of prominent peaks in the filter frequency response. The signal model is implemented as a Pure Data  patch for live performance using a standard MIDI keyboard.