Violin Impulse Response Length and Perceptions of Acceptability

The design, execution and analysis of a double-blind listening study is described, in which participants gave preference ratings for nine versions of the same piece of music, obtained by convolving violin impulse responses, of different length, with the original piece played on an electric instrument and stored in digital form. The original impulse response, with a length of 91.4 ms was measured from a Stradivarius violin and progressively degraded by shortening its length. The participants, who were all trained musicians, were asked to record their preferences based on personal taste, not perceived measures of quality. Analysis of the data revealed a sigmoid relationship between preference and length of impulse response. Emulated music generated using short impulse responses was the least preferred, and this aversion was reasonably constant for responses shorter than 2.7 ms. However, and perhaps surprisingly, impulse responses of only 5.78 ms were deemed acceptable. Extending the length beyond this value had little effect on the attributed preferences. Between these two values, there was a steep increase in the assigned scores, suggesting a sigmoid relationship. The findings are of theoretical interest for psychoacoustics and can be applied to the development of electronic devices that emulate stringed instruments in real time.