Timbre space as synthesis space: towards a navigation based approach to timbre specification

Much research into timbre, its perception and classification over the last forty years has modelled timbre as an n-dimensional co-ordinate space or timbre space, whose axes are measurable acoustical quantities (variously, spectral density, simultaneity of partial onsets etc). Typically, these spaces have been constructed from data generated from similarity/dissimilarity listening tests, using multidimensional scaling (MDS) analysis techniques. Our current research is the computer assisted synthesis of new timbres using a timbre space search strategy, in which a previously constructed simple timbre space is used as a search space by an algorithm designed to synthesize desired new timbres steered by iterative user input. The success of such an algorithm clearly depends on establishing suitable mapping between its quantifiable features and its perceptual features. We therefore present here, firstly, some of the findings of a series of listening tests aimed at establishing the perceptual topography and granularity of a simple, predefined timbre space, and secondly, the results of preliminary tests of two search strategies designed to navigate this space. The behaviour of these strategies in a circumscribed space of this kind, together with the corresponding user experience is intended to provide a baseline to applications in a more complex space

Understanding concurrent earcons: applying auditory scene analysis principles to concurrent earcon recognition

Two investigations into the identification of concurrently presented, structured sounds, called earcons were carried out. One of the experiments investigated how varying the number of concurrently presented earcons affected their identification. It was found that varying the number had a significant effect on the proportion of earcons identified. Reducing the number of concurrently presented earcons lead to a general increase in the proportion of presented earcons successfully identified. The second experiment investigated how modifying the earcons and their presentation, using techniques influenced by auditory scene analysis, affected earcon identification. It was found that both modifying the earcons such that each was presented with a unique timbre, and altering their presentation such that there was a 300 ms onset-to-onset time delay between each earcon were found to significantly increase identification. Guidelines were drawn from this work to assist future interface designers when incorporating concurrently presented earcons

Pitch discrimination is better for synthetic timbre than natural musical instrument timbres despite familiarity

Pitch discrimination is better for complex tones than pure tones, but how pitch discrimination differs between natural and artificial sounds is not fully understood. This study compared pitch discrimination thresholds for flat-spectrum harmonic complex tones with those for natural sounds played by musical instruments of three different timbres (violin, trumpet, and flute). To investigate whether natural familiarity with sounds of particular timbres affects pitch discrimination thresholds, this study recruited non-musicians and musicians who were trained on one of the three instruments. We found that flautists and trumpeters could discriminate smaller differences in pitch for artificial flat-spectrum tones, despite their unfamiliar timbre, than for sounds played by musical instruments, which are regularly heard in everyday life (particularly by musicians who play those instruments). Furthermore, thresholds were no better for the instrument a musician was trained to play than for other instruments, suggesting that even extensive experience listening to and producing sounds of particular timbres does not reliably improve pitch discrimination thresholds for those timbres. The results show that timbre familiarity provides minimal improvements to auditory acuity, and physical acoustics (e.g., the presence of equal-amplitude harmonics) determine pitch discrimination thresholds more than does experience with natural sounds and timbre-specific training

Evaluation of live human-computer music-making: Quantitative and qualitative approaches

NOTICE: this is the author’s version of a work that was accepted for publication in International Journal of Human-Computer Studies. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in International Journal of Human-Computer Studies, [VOL 67,ISS 11(2009)] DOI: 10.1016/j.ijhcs.2009.05.00

A study of the growth in speech sound discrimination ability of kindergarten children

Thesis (Ed.M.)--Boston Universit

The cognitive organization of music knowledge: a clinical analysis

Despite much recent interest in the clinical neuroscience of music processing, the cognitive organization of music as a domain of non-verbal knowledge has been little studied. Here we addressed this issue systematically in two expert musicians with clinical diagnoses of semantic dementia and Alzheimer’s disease, in comparison with a control group of healthy expert musicians. In a series of neuropsychological experiments, we investigated associative knowledge of musical compositions (musical objects), musical emotions, musical instruments (musical sources) and music notation (musical symbols). These aspects of music knowledge were assessed in relation to musical perceptual abilities and extra-musical neuropsychological functions. The patient with semantic dementia showed relatively preserved recognition of musical compositions and musical symbols despite severely impaired recognition of musical emotions and musical instruments from sound. In contrast, the patient with Alzheimer’s disease showed impaired recognition of compositions, with somewhat better recognition of composer and musical era, and impaired comprehension of musical symbols, but normal recognition of musical emotions and musical instruments from sound. The findings suggest that music knowledge is fractionated, and superordinate musical knowledge is relatively more robust than knowledge of particular music. We propose that music constitutes a distinct domain of non-verbal knowledge but shares certain cognitive organizational features with other brain knowledge systems. Within the domain of music knowledge, dissociable cognitive mechanisms process knowledge derived from physical sources and the knowledge of abstract musical entities

Evaluation of the perceptual magnet effect and categorical perception for musical timbre

Recent auditory research has raised fundamental questions about the perceptual magnet effect (PME), where discrimination performance is poorer for stimuli that approach best exemplars of a phonetic category. It has been suggested that the effect reflects inter-categorical comparisons, and might not generalize to nonspeech. Three experiments addressed these concerns. In Experiment 1 prototype and non-prototype stimuli were determined from goodness ratings of synthesized (violin) timbres varying in center frequencies of F1 and F2 formants. Experiment 2 evaluated for a PME using discrimination data, and influences from other categories by comparing goodness ratings from stimuli in prototype, non-prototype, and no context conditions. Experiment 3 used labeling and discrimination tasks to assess if categorical perception occurs with timbres. Despite having stimuli reliably identified to be within the intended category, no PME was found. It is suggested that the PME, if a real phenomenon, is too difficult to tease apart from categorization tendencies

A BRIEF REVIEW OF SELECTED RESEARCH-BASED STRATEGIES FOR HELPING YOUNG SINGERS MATCH PITCH

The purpose of this review of literature was to identify ways to help varying levels of novice singers manage and improve their vocal pitch matching ability. The review identified the work of prominent pedagogues and researchers. The literature review revealed that techniques aiding the novice singer yield varying levels of success. Most of the research showed that remedial techniques work best in small groups, one-on-one settings, and solo singing. The research did not address the issue of effective teaching and its effect with regard to student achievement (e.g., classroom management and issues related to effective or ineffective teaching ability)