Real-Time Emulation of the Acoustic Violin using Convolution and Arbitrary Equalization

An audio effects processor is described that modifies in real-time the signal generated by an electric violin, to resemble closely the tonal qualities of an equivalent acoustic instrument. The device operates by convolving the incoming signal with an impulse response measured from an acoustic violin; since accurate measurement of the impulse response is critical, it is described in some detail in the text. The system can store sixteen such responses, so is ideally suited for use in listening studies in which the timbres of different emulations are assessed. The device further incorporates a uniquely adjustable arbitrary equalizer and a blender, optionally invoked after the convolution stage, which allow the performer to modify the instrument voice to suit personnel preferences or room acoustics. The system has been evaluated in a blind listening study, in which participants were asked to rank emulations based on a range of violins of varying quality, including Old Italian models. Statistical analysis suggests strongly that high quality instruments were favored over the raw electric sound and the cheap student model; moreover, the study confirmed that the improvement in tonal quality was convincing and realistic, conveying many of the tonal nuances of the emulated wooden instrument.