Estimation and Tonal Analysis of the Angle of Attack in a Classical Guitar Performance

The classical guitar tone can be controlled by a number of gestural parameters performed by the player, including the plucking point position, the angle of attack, and the angle of release. In this study, we developed a video-based approach for estimating the angle of attack from a classical guitar performance. Our angle of attack estimation system achieved an average absolute error of 3.32 degrees on our data set containing 270 samples with varying angles of attack and plucking point positions. Moreover, we discovered through statistical analysis that the two gestural parameters indeed significantly affect the audio feature that describes the degree of brightness of the produced guitar sound, namely the spectral centroid. We were able to generate regression models with fair regression scores that correlate the spectral centroid with the two gestural parameters, and we further discovered that the regression scores decrease with increasing fundamental frequency of the classical guitar sound.