Factors in human recognition of timbre lexicons generated by data clustering

Since the development of sound recording technologies, the palette of sound timbres available for music creation was extended way beyond traditional musical instruments. The organization and categorization of timbre has been a common endeavor. The availability of large databases of sound clips provides an opportunity for obtaining datadriven timbre categorizations via content-based clustering. In this article we describe an experiment aimed at understanding what factors influence the process of learning a given clustering of sound samples. We clustered a large database of short sound clips, and analyzed the success of participants in assigning sounds to the “correct” clusters after listening to a few examples of each. The results of the experiment suggest a number of relevant factors related both to the strategies followed by users and to the quality measures of the clustering solution, which can guide the design of creative applications based on audio clip clustering

Proceedings of the 7th Sound and Music Computing Conference

Proceedings of the SMC2010 - 7th Sound and Music Computing Conference, July 21st - July 24th 2010

Using morphological description for generic sound retrieval

Systems for sound retrieval are usually “source-centred”. This means that retrieval is based on using the proper keywords that define or specify a sound source. Although this type of description is of great interest, it is very difficult to implement it into realistic automatic labelling systems because of the necessity of dealing with thousands of categories, hence with thousands of different sound models. Moreover, digitally synthesised or transformed sounds, which are frequently used in most of the contemporary popular music, have no identifiable sources. We propose a description framework, based on Schaeffer’s research on a generalised solfeggio which could be applied to any type of sounds. He defined some morphological description criteria, based on intrinsic perceptual qualities of sound, which doesn’t refer to the cause or the meaning of a sound. We describe more specifically experiments on automatic extraction of morphological descriptors

Representing music as work in progress

ABSTRACT In this chapter we discuss an approach to music representation that supports collaborative composition given current practices based on digital audio. A music work is represented as a directed graph that encodes sequences and layers of sound objects. We discuss graph grammars as a general framework for this representation. From a grammar perspective, we analyze the use of XML for storing production rules, music structure, and references to audio files. We describe an example implementation of this approach

Characterization and exploitation of community structure in cover song networks

The use of community detection algorithms is explored within the framework of cover song identification, i.e. the automatic detection of different audio renditions of the same underlying musical piece. Until now, this task has been posed as a typical query-by-example task, where one submits a query song and the system retrieves a list of possible matches ranked by their similarity to the query. In this work, we propose a new approach which uses song communities to provide more relevant answers to a given query. Starting from the output of a state-of-the-art system, songs are embedded in a complex weighted network whose links represent similarity (related musical content). Communities inside the network are then recognized as groups of covers and this information is used to enhance the results of the system. In particular, we show that this approach increases both the coherence and the accuracy of the system. Furthermore, we provide insight into the internal organization of individual cover song communities, showing that there is a tendency for the original song to be central within the community. We postulate that the methods and results presented here could be relevant to other query-by-example tasks

Report of the Scientific Committee of the Spanish Agency for Food Safety and Nutrition (AESAN) in relation to the effect on the Spanish population of the derogation of national regulation on maximum allowed limits for aflatoxins B1, B2, G1 and G2 in food

Las aflatoxinas son metabolitos tóxicos producidos por varias especies de hongos del género Aspergillus que crecen en plantas y alimentos de origen vegetal. De entre todas ellas (B1, B2, G1, G2, M1 y M2), destaca desde el punto de vista de la seguridad alimentaria la aflatoxina B1, tanto por ser la más prevalente en alimentos como la más tóxica para los seres humanos. La Unión Europea, debido a la toxicidad de estos compuestos y con el fin de garantizar una protección eficaz de la salud pública, ha establecido mediante el Reglamento (CE) Nº 1881/2006 contenidos máximos para la aflatoxina B1 y la suma de aflatoxinas B1, B2, G1 y G2 en diversos alimentos, entre los que se incluyen aquellos en los cuales la contaminación por este tipo de toxinas resulta más frecuente y puede resultar más peligrosa para la salud humana. En España, previamente a lo establecido por el Reglamento (CE) Nº 1881/2006, ya se dispone de una norma reguladora, el Real Decreto 475/1988, en el cual se establecen límites máximos permitidos de aflatoxinas B1, B2, G1 y G2 en alimentos para consumo humano de 10 μg/kg para la suma de dichas aflatoxinas y de 5 μg/kg para la aflatoxina B1. Si bien es cierto que el Reglamento (CE) Nº 1881/2006 cubre los alimentos que de manera más habitual pueden representar un riesgo para la salud humana originado por la presencia de aflatoxinas, existen trabajos científicos en los cuales se ha demostrado la presencia tanto de aflatoxinas totales como de aflatoxina B1 en alimentos no incluídos en el Reglamento (CE) Nº 1881/2006 en cantidades superiores a las establecidas como límites en el Real Decreto 475/1988. Por este motivo, y sin perjuicio de las medidas de gestión que sean pertinentes, el Comité Científico considera que, en este momento y hasta que se disponga de datos representativos de la presencia de aflatoxinas en algunos alimentos no incluídos en la legislación europea tales como la chufa, el Real Decreto 475/1988 que regula los límites máximos permitidos de aflatoxinas B1, B2, G1 y G2 ofrece un nivel de protección significativo para el consumidor respecto a determinados alimentos no regulados por el Reglamento (CE) Nº 1881/2006.Aflatoxins are toxic metabolites produced by some species of molds belonging to the genus Aspergillus which grow on plants and vegetable-origin foods. Among the aflatoxins that can be found (B1, B2, G1, G2, M1 and M2), from a food safety point of view the most remarkable is aflatoxin B1, because it is the most prevalent in foods and toxic for humans. Due to the toxicity of these substances and to protect consumers’ health, the European Union has stated maximum residue limits (MRL) for aflatoxins in foods, in the Commission Regulations (EC) No 1881/2006. MRL have been established for aflatoxin B1 and the sum of B1, B2, G1 and G2 in different foods, including those in which contamination with these kind of toxins is more frequent and can be more dangerous for human health. The Spanish Royal Decree 475/1988, approved before the Commission Regulation (EC) No 1881/ 2006, sets MRL for the aflatoxins in food for human consumption; 5 μg/kg for aflatoxin B1 and 10 μg/ kg for the sum of aflatoxin B1, B2, G1 and G2. Despite the Commission Regulation (EC) No 1881/2006 includes food which most could usually pose a risk for human health, specific papers have demonstrated the presence of total aflatoxins and aflatoxin B1 in foods not included in the Commission Regulation (EC) No 1881/2006, even at higher concentrations than those set up by the Spanish Royal Decree 475/1988. For this reason, notwithstanding the management measures that are pertinent, the scientific committee considers that, while there are no more data about maximum limits for these substances other food samples different than those included in the previously mentioned legislations (as tiger nuts or other doubtful foods regarding their producing conditions) the Royal Decree 475/1988 offers a significant protection for consumers

Zipf's Law in Short-Time Timbral Codings of Speech, Music, and Environmental Sound Signals

Timbre is a key perceptual feature that allows discrimination between different sounds. Timbral sensations are highly dependent on the temporal evolution of the power spectrum of an audio signal. In order to quantitatively characterize such sensations, the shape of the power spectrum has to be encoded in a way that preserves certain physical and perceptual properties. Therefore, it is common practice to encode short-time power spectra using psychoacoustical frequency scales. In this paper, we study and characterize the statistical properties of such encodings, here called timbral code-words. In particular, we report on rank-frequency distributions of timbral code-words extracted from 740 hours of audio coming from disparate sources such as speech, music, and environmental sounds. Analogously to text corpora, we find a heavy-tailed Zipfian distribution with exponent close to one. Importantly, this distribution is found independently of different encoding decisions and regardless of the audio source. Further analysis on the intrinsic characteristics of most and least frequent code-words reveals that the most frequent code-words tend to have a more homogeneous structure. We also find that speech and music databases have specific, distinctive code-words while, in the case of the environmental sounds, this database-specific code-words are not present. Finally, we find that a Yule-Simon process with memory provides a reasonable quantitative approximation for our data, suggesting the existence of a common simple generative mechanism for all considered sound sources

MIRages: an account of music audio extractors, semantic description and context-awareness, in the three ages of MIR

This tesis reports on research carried out and published during the last twenty years on different problems of Music Information Retrieval (MIR). We organize the text as a personal account and critical reflection along four hypothesized ages that have shaped the evolution of MIR. In the age of feature extractors, we present work on features to describe sounds and music, especially timbre and tonal aspects. In the age of semantic descriptors work on describing music with high-level concepts, such as mood, instruments, similarities, cover versions or genres, usually inferred with machine learning from annotated collections is reported. In the age of context-aware systems we report on user models for recommendation and for avatar generation, in addition to factors that influence music listening decisions. We finally discuss the possibility of a more recent age of creative systems where MIR features, classifiers, models and evaluation methodologies aid to enhance or expand music creation.Aquesta tesi informa sobre recerca realitzada i publicada durant els últims vint anys en diferents problemes de Recuperació d'Informació Musical (MIR). Organitzem el text com a visió personal i reflexió crítica i utilitzant quatre hipotètiques edats que han configurat l'evolució del MIR. A l'edat dels extractors de característiques, presentem treballs sobre trets per a descriure sons i música, especialment timbre i aspectes tonals. A l'edat dels descriptors semàntics es treballa en la descripció de música amb conceptes d'alt nivell, com l'estat d'ànim, els instruments, les similituds, les versions musicals o els gèneres, generalment deduïts amb l'aprenentatge automàtic a partir de col·leccions anotades. En l'era dels sistemes sensibles al context, informem sobre models d'usuaris amb l’objectiu de fer recomanacions musicals i generació d'avatars, a més de factors que influeixen en les decisions d'escoltar música. S’esmenta, finalmente, una posible i més recent edat dels sistemes creatius on els descriptors, classificadors, models i metodologies d'avaluació de MIR ajuden a potenciar o ampliar la creació musical.  Programa de doctorat en Tecnologies de la Informació i les Comunicacion

Comparative Analysis of Music Recordings from Western and Non-Western traditions by Automatic Tonal Feature Extraction

The automatic analysis of large musical corpora by means of computational models overcomes some limitations of manual analysis, and the unavailability of scores for most existing music makes necessary to work with audio recordings. Until now, research on this area has focused on music from the Western tradition. Nevertheless, we might ask if the available methods are suitable when analyzing music from other cultures. We present an empirical approach to the comparative analysis of audio recordings, focusing on tonal features and data mining techniques. Tonal features are related to the pitch class distribution, pitch range and employed scale, gamut and tuning system. We provide our initial but promising results obtained when trying to automatically distinguish music from Western and non- Western traditions; we analyze which descriptors are most relevant and study their distribution over 1500 pieces from different traditions and styles. As a result, some feature distributions differ for Western and non-Western music, and the obtained classification accuracy is higher than 80% for different classification algorithms and an independent test set. These results show that automatic description of audio signals together with data mining techniques provide means to characterize huge music collections from different traditions and complement musicological manual analyses