An IIR synthesis method for plucked-string instruments with embedded portamento

Portamento and vibrato are the two most used playing techniques for string instruments. For some specific instruments, such as the Gu-Chin (a Chinese traditional zither), the range of portamento can be close to an octave. The sound becomes unnatural in such cases if wavetable techniques are used. A new infinite-impulse-response (IIR) synthesis model with embedded portamento is proposed. This method can closely synthesize a specific pluckedstring instrument and also perform portamento and vibrato efficiently. The model parameters for synthesizing a specific instrument are obtained by using a neural network training algorithm. A variable-length delay line is embedded such that the special effects can be obtained by changing the system parameters in resynthesis. The proposed method has been successfully tested over many different kinds of plucked-string instruments. The computational complexity of synthesis is close to that of an ordinary IIR filter and depends on its order. The complexity of the proposed model is higher if more accuracy is desired. Like DWF-based approaches, memory is required to store a small segment of excitation waveform.