Sølvi Ystad

Sound quality assessment of wood for xylophone bars

Xylophone sounds produced by striking wooden bars with a mallet are strongly influenced by the mechanical properties of the wood species chosen by the xylophone maker. In this paper, we address the relationship between the sound quality based on the timbre attribute of impacted wooden bars and the physical parameters characterizing wood species. For this, a methodology is proposed that associates an analysis-synthesis process and a perceptual classification test. Sounds generated by impacting 59 wooden bars of different species but with the same geometry were recorded and classified by a renowned instrument maker. The sounds were further digitally processed and adjusted to the same pitch before being once again classified. The processing is based on a physical model ensuring the main characteristics of the wood are preserved during the sound transformation. Statistical analysis of both classifications showed the influence of the pitch in the xylophone maker judgement and pointed out the importance of two timbre descriptors: the frequency-dependent damping and the spectral bandwidth. These descriptors are linked with physical and anatomical characteristics of wood species, providing new clues in the choice of attractive wood species from a musical point of view.

The effect of real-time auditory feedback on learning new characters

The present study investigated the effect of handwriting sonification on graphomotor learning. Thirty-two adults, distributed in two groups, learned four new characters with their non-dominant hand. The experimental design included a pre-test, a training session, and two post-tests, one just after the training sessions and another 24h later. Two characters were learned with and two without real-time auditory feedback (FB). The first group first learned the two non-sonified characters and then the two sonified characters whereas the reverse order was adopted for the second group. Results revealed that auditory FB improved the speed and fluency of handwriting movements but reduced, in the short-term only, the spatial accuracy of the trace. Transforming kinematic variables into sounds allows the writer to perceive his/her movement in addition to the written trace and this might facilitate handwriting learning. However, there were no differential effects of auditory FB, neither long-term nor short-term for the subjects who first learned the characters with auditory FB. We hypothesize that the positive effect on the handwriting kinematics was transferred to characters learned without FB. This transfer effect of the auditory FB is discussed in light of the Theory of Event Coding.

From Sound to Shape: Auditory Perception of Drawing Movements

This study investigates the human ability to perceive biological movements through friction sounds produced by drawings and, furthermore, the ability to recover drawn shapes from the friction sounds generated. In a first experiment, friction sounds, real-time synthesized and modulated by the velocity profile of the drawing gesture, revealed that subjects associated a biological movement to those sounds whose timbre variations were generated by velocity profiles following the 1/3 power law. This finding demonstrates that sounds can adequately inform about human movements if their acoustic characteristics are in accordance with the kinematic rule governing actual movements. Further investigations of our ability to recognize drawn shapes were carried out in 2 association tasks in which both recorded and synthesized sounds had to be associated to both distinct and similar visual shapes. Results revealed that, for both synthesized and recorded sounds, subjects made correct associations for distinct shapes, although some confusion was observed for similar shapes. The comparisons made between recorded and synthesized sounds lead to conclude that the timbre variations induced by the velocity profile enabled the shape recognition. The results are discussed in the context of the ecological and ideomotor frameworks.

From clarinet control to timbre perception

This study investigates the relationships between the control gestures of the clarinet, the generated timbres and their perceptual representation. The understanding of such relationships can provide great interest in several research contexts: synthesis and control (e.g., to improve the quality of current synthesis models), music analysis and perception (e.g., to study music performance), and music information retrieval (e.g., to find relevant acoustical descriptors for automatic instrument and/or performer identification). A physics-based model was used to generate synthetic clarinet tones by varying the main control parameters of the model (related to the blowing pressure and lip pressure on the reed). 16 participants had to rate the dissimilarities between pairs of different tones and describe the factors on which they based their judgments in a questionnaire. The collected data were subjected to various statistical analyses (multidimensional scaling and hierarchical clustering) in order to obtain a low-dimensional spatial configuration (timbre space) which best represents the dissimilarity ratings. The structure of the clarinet timbre space was interpreted both in terms of control parameters and acoustical descriptors. The analyses revealed a 3-dimensional timbre space, whose dimensions were well correlated to the Attack Time, the Spectral Centroid, and the Odd/Even Ratio. Comparisons of natural and synthetic clarinet tones showed that the Odd/Even Ratio appears to be a good predictor of the beating reed situation, specific to single-reed instruments.

An intuitive synthesizer of continuous-interaction sounds: Rubbing, scratching, and rolling

In this article, we propose a control strategy for synthesized continuous-interaction sounds. The framework of our research is based on the action–object paradigm that describes the sound as the result of an action on an object and that presumes the existence of sound invariants (i.e., perceptually relevant signal morphologies that carry information about the actions or the objects attributes). Auditory cues are investigated here for the evocations of rubbing, scratching, and rolling interactions. A generic sound-synthesis model that simulates these interactions is detailed. We then suggest an intuitive control strategy that enables users to navigate continuously from one interaction to another in an “action space,” thereby offering the possibility to simulate morphed interactions—for instance, ones that morph between rubbing and rolling.

From Sounds to Music and Emotions

The constant growth of online music dataset and applica- tions has required advances in MIR Research. Music genres and anno- tated mood have received much attention in the last decades as descrip- tors of content-based systems. However, their inherent relationship is rarely explored in the literature. Here, we investigate whether or not the presence of tonal and rhythmic motifs in the melody can be used for establishing a relationship between genres and subjective aspects such as the mood,dynamism and emotion. Our approach uses symbolic rep- resentation of music and is applied to eight dierent genres.

Additivity of nonsimultaneous masking for short Gaussian-shaped sinusoidsa)

The additivity of nonsimultaneous masking was studied using Gaussian-shaped tone pulses (referred to as Gaussians) as masker and target stimuli. Combinations of up to four temporally separated Gaussian maskers with an equivalent rectangular bandwidth of 600 Hz and an equivalent rectangular duration of 1.7 ms were tested. Each masker was level-adjusted to produce approximately 8 dB of masking. Excess masking (exceeding linear additivity) was generally stronger than reported in the literature for longer maskers and comparable target levels. A model incorporating a compressive input/output function, followed by a linear summation stage, underestimated excess masking when using an input/output function derived from literature data for longer maskers and comparable target levels. The data could be predicted with a more compressive input/output function. Stronger compression may be explained by assuming that the Gaussian stimuli were too short to evoke the medial olivocochlear reflex (MOCR), whereas for longer maskers tested previously the MOCR caused reduced compression. Overall, the interpretation of the data suggests strong basilar membrane compression for very short stimuli.

Validation of the French sensory gating inventory: A confirmatory factor analysis

The Sensory Gating Inventory (SGI) is an instrument investigating daily experiences of sensory gating deficit developed for English speaking schizophrenia patients. The purpose of this study is to design and validate a French version of the SGI. A forward-backward translation of the SGI was performed. The psychometric properties of the French SGI version were analyzed. A confirmatory factor analysis (CFA) was carried out to determine whether factor structure of the French version is similar to the original English version. In a sample of 363 healthy subjects (mean age=31.8 years, S.D.=12.2 years) the validation process revealed satisfactory psychometric properties: the internal consistency reliability was confirmed for each dimension; each item achieved the 0.40 standard threshold for item-internal consistency; each item was more highly correlated with its contributive dimension than with the other dimensions; and based on a CFA, we found a 4-factor structure for the French version of the SGI similar to the original instrument. Test-retest reliability was not determined. The French version of the SGI is a psychometrically sound self-report for measuring phenomenological sensory gating experiences.

Exploring Music Contents

This book constitutes the thoroughly refereed post-proceedings of the 7th International Symposium on Computer Music Modeling and Retrieval, CMMR 2010, held in Malaga, Spain, in June 2010. The 22 revised full papers presented were specially reviewed and revised for inclusion in this proceedings volume. The book is divided in five main chapters which reflect the present challenges within the field of computer music modeling and retrieval. The chapters range from music interaction, composition tools and sound source separation to data mining and music libraries. One chapter is also dedicated to perceptual and cognitive aspects that are currently subject to increased interest in the MIR community.

Perceptive and cognitive evaluation of a piano synthesis model

The aim of this work is to use subjective evaluations of sounds produced by a piano synthesis model to determine the perceptual influence on phenomena involved in sound production. The specificity of musical sounds is that they are intended for perception and judgments by human beings. It is therefore necessary, in order to evaluate the acoustic qualities of a musical instrument or a sound model, to introduce a research approach which takes into account the evaluation of the sound quality by human beings. As a first approach we synthesize a number of piano sounds. We then evaluate the quality of the perceived acoustic signal by questioning a group of persons. We hereby try to link the models parameters to semantic descriptors obtained from these persons and to more classical perceptual signal descriptors. This approach should give a better understanding of how the models parameters are linked to cognitive representations and more generally give new clues to cognitive descriptions of timbre of musical sounds.