Good vibrations: Guiding body movements with vibrotactile feedback

We describe the ongoing development of a system to support the teaching of good posture and bowing technique to novice violin players. Using an inertial motion capture system we can track in real-time a player’s bowing action and how it deviates from a target trajectory set by their music teacher. The system provides real-time vibrotactile feedback on the correctness of the student’s posture and bowing action. We present the findings of an initial study that shows that vibrotactile feedback can guide arm movements in one and two dimension pointing tasks. The advantages of vibrotactile feedback for teaching basic bowing technique to novice violin players are that it does not place demands on the students’ visual and auditory systems which are already heavily involved in the activity of music making, and is understood with little training

Towards a real-time system for teaching novices good violin bowing technique

We describe the ongoing development of a system to support the teaching of good posture and bowing technique to novice violin players. Using an inertial motion capture system we can track in real-time: i) a player’s bowing action (and measure how it deviates from a target trajectory); ii) whether the player is holding their violin correctly. We detail some initial experiments that show that vibrotactile feedback can guide arm movements in one and two dimensions. We then present some preliminary findings from integrating the motion capture and feedback components into a prototype real-time training system. The advantages of vibrotactile feedback are that: i) it does not use the students’ visual and auditory systems which are already involved in the activity of music making; ii) it is an intuitive way to guide body movements

IMUTUS - an Interactive Music Tuition System

International audienceIMUTUS is a European project that aims at the development of an open platform for training students on non-MIDI musical instruments, as well as to acquire theoretical music knowledge. The project involves many components oriented towards a new approach of music learning. After a brief overview of the system, the performance evaluation module and the music score processing components are described to show how they enforce the pedagogical approach

Mechanics and acoustics of violin bowing : Freedom, constraints and control in performance

This thesis addresses sound production in bowed-string instruments from two perspectives: the physics of the bowed string, and bow control in performance. Violin performance is characterized by an intimate connection between the player and the instrument, allowing for a continuous control of the sound via the main bowing parameters (bow velocity, bow force and bow-bridge distance), but imposing constraints as well. In the four included studies the focus is gradually shifted from the physics of bow-string interaction to the control exerted by the player. In the first two studies the available bowing parameter space was explored using a bowing machine, by systematically probing combinations of bow velocity, bow force and bow-bridge distance. This allowed for an empirical evaluation of the maximum and minimum bow force required for the production of a regular string tone, characterized by Helmholtz motion. Comparison of the found bow-force limits with theoretical predictions by Schelleng revealed a number of striking discrepancies, in particular regarding minimum bow force. The observations, in combination with bowed-string simulations, provided new insights in the mechanism of breakdown of Helmholtz motion at low bow forces. In the second study the influence of the main bowing parameters on aspects of sound quality was analyzed in detail. It was found that bow force was totally dominating the control of the spectral centroid, which is related to the perceived brightness of the tone. Pitch flattening could be clearly observed when approaching the upper bow-force limit, confirming its role as a practical limit in performance. The last two studies were focused on the measurement of bowing gestures in violin and viola performance. A method was developed for accurate and complete measurement of the main bowing parameters, as well as the bow angles skewness, inclination and tilt. The setup was used in a large performance study. The analyses revealed clear strategies in the use of the main bowing parameters, which could be related to the constraints imposed by the upper and lower bow-force limits and pitch flattening. Further, it was shown that two bow angles (skewness and tilt) were systematically used for controlling dynamic level; skewness played an important role in changing bow-bridge distance in crescendo and diminuendo notes, and tilt was used to control the gradation of bow force. Visualizations and animations of the collected bowing gestures revealed significant features of sophisticated bow control in complex bowing patterns.QC 2010080

Mechanics and acoustics of violin bowing : Freedom, constraints and control in performance

This thesis addresses sound production in bowed-string instruments from two perspectives: the physics of the bowed string, and bow control in performance. Violin performance is characterized by an intimate connection between the player and the instrument, allowing for a continuous control of the sound via the main bowing parameters (bow velocity, bow force and bow-bridge distance), but imposing constraints as well. In the four included studies the focus is gradually shifted from the physics of bow-string interaction to the control exerted by the player. In the first two studies the available bowing parameter space was explored using a bowing machine, by systematically probing combinations of bow velocity, bow force and bow-bridge distance. This allowed for an empirical evaluation of the maximum and minimum bow force required for the production of a regular string tone, characterized by Helmholtz motion. Comparison of the found bow-force limits with theoretical predictions by Schelleng revealed a number of striking discrepancies, in particular regarding minimum bow force. The observations, in combination with bowed-string simulations, provided new insights in the mechanism of breakdown of Helmholtz motion at low bow forces. In the second study the influence of the main bowing parameters on aspects of sound quality was analyzed in detail. It was found that bow force was totally dominating the control of the spectral centroid, which is related to the perceived brightness of the tone. Pitch flattening could be clearly observed when approaching the upper bow-force limit, confirming its role as a practical limit in performance. The last two studies were focused on the measurement of bowing gestures in violin and viola performance. A method was developed for accurate and complete measurement of the main bowing parameters, as well as the bow angles skewness, inclination and tilt. The setup was used in a large performance study. The analyses revealed clear strategies in the use of the main bowing parameters, which could be related to the constraints imposed by the upper and lower bow-force limits and pitch flattening. Further, it was shown that two bow angles (skewness and tilt) were systematically used for controlling dynamic level; skewness played an important role in changing bow-bridge distance in crescendo and diminuendo notes, and tilt was used to control the gradation of bow force. Visualizations and animations of the collected bowing gestures revealed significant features of sophisticated bow control in complex bowing patterns.QC 2010080

Combining accelerometer and video camera: reconstruction of bow velocity profiles

A cost-effective method was developed for the estimation of the bow velocity in violin playing, using an accelerometer on the bow in combination with point tracking using a standard video camera. The video data are used to detect the moments of bow direction changes. This information is used for piece-wise integration of the accelerometer signal, resulting in a drift-free reconstructed velocity signal with a high temporal resolution. The method was evaluated using a 3D motion capturing system, providing a reliable reference of the actual bow velocity. The method showed good results when the accelerometer and video stream are synchronized. Additional latency and jitter of the camera stream can importantly decrease the performance of the method, depending on the bow stroke type

Towards a rule-based model for violin vibrato

Vibrato is one of the most important expressive parameters that players can control when rendering a piece of music. The simulation of vibrato, in systems for automatic music performance, is still an open problem. A mere regular periodic modulation of pitch generally yields unsatisfactory results, sounding both unnatural and mechanical. An appropriate control of vibrato rate and vibrato extent is a major requirement of a successful vibrato model. The goal of the present work was to develop a generative, rule-based model for expressive violin vibrato. Measurements of vibrato as performed by professional violinists were used for this purpose. The model generates vibrato rate and extent envelopes, which are used to control a sampled violin synthesizer.