7,807 research outputs found
Toward an ecological conception of timbre
This paper is part of a series in which we had worked in the last 6 months, and, specifically, intend to investigate the notion of timbre through the ecological perspective proposed by James Gibson in his Theory of Direct Perception. First of all, we discussed the traditional approach to timbre, mainly as developed in acoustics and psychoacoustics. Later, we proposed a new conception of timbre that was born in concepts of ecological approach.
The ecological approach to perception proposed by Gibson (1966, 1979) presupposes a level of analysis of perceptual stimulated that includes, but is quite broader than the usual physical aspect. Gibson suggests as focus the relationship between the perceiver and his environment. At the core of this approach, is the notion of affordances, invariant combinations of properties at the ecological level, taken with reference to the anatomy and action systems of species or individual, and also with reference to its biological and social needs. Objects and events are understood as relates to a perceiving organism by the meaning of structured information, thus affording possibilities of action by the organism.
Event perception aims at identifying properties of events to specify changes of the environment that are relevant to the organism. The perception of form is understood as a special instance of event perception, which is the identity of an object depends on the nature of the events in which is involved and what remains invariant over time. From this perspective, perception is not in any sense created by the brain, but is a part of the world where information can be found. Consequently, an ecological approach represents a form of direct realism that opposes the indirect realist based on predominant approaches to perception borrowed from psychoacoustics and computational approach
On the acoustical theory of the trumpet : is it sound? : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Mathematics at Massey University, New Zealand
Newton's Second Law of Motion for one-dimensional inviscid flow of an incompressible fluid, in the absence of external forces, is often expressed in a form known as Bernoulli's equation:
There are two distinct forms of Bernoulli's equation used in the system of equations which is commonly considered to describe sound production in a trumpet. The flow between the trumpeter's lips is, in the literature, assumed to be quasi-steady. From this assumption, the first term of the above Bernoulli equation is omitted, since it is then small in comparison to the other two terms. The flow within the trumpet itself is considered to consist of small fluctuations about some mean velocity and pressure. A linearized version of Bernoulli's equation (as used in the equations of linear acoustics) is then adequate to describe the flow. In this case it is the second term of the above equation which is neglected, and the first term is retained. Given that the flow between the trumpeter's lips is that same flow which enters the trumpet itself, a newcomer to the field of trumpet modelling might wonder whether the accepted model is really correct when these two distinct versions of the Bernoulli Equation are used side by side. This thesis addresses this question, and raises others that arise from a review of the standard theory of trumpet physics. The investigation comprises analytical and experimental components, as well as computational simulations. No evidence has been found to support the assumption of quasi-steady flow between the lips of a trumpeter. An alternative flow equation is proposed, and conditions given for its applicability. [NB: Mathematical/chemical formulae or equations have been omitted from the abstract due to website limitations. Please read the full text PDF file for a complete abstract.
Pitch-Informed Solo and Accompaniment Separation
ï»żDas Thema dieser Dissertation ist die Entwicklung eines Systems zur
Tonhöhen-informierten Quellentrennung von Musiksignalen in Soloinstrument
und Begleitung. Dieses ist geeignet, die dominanten Instrumente aus einem
MusikstĂŒck zu isolieren, unabhĂ€ngig von der Art des Instruments, der
Begleitung und Stilrichtung. Dabei werden nur einstimmige
Melodieinstrumente in Betracht gezogen. Die Musikaufnahmen liegen monaural
vor, es kann also keine zusÀtzliche Information aus der Verteilung der
Instrumente im Stereo-Panorama gewonnen werden.
Die entwickelte Methode nutzt Tonhöhen-Information als Basis fĂŒr eine
sinusoidale Modellierung der spektralen Eigenschaften des Soloinstruments
aus dem Musikmischsignal. Anstatt die spektralen Informationen pro Frame zu
bestimmen, werden in der vorgeschlagenen Methode Tonobjekte fĂŒr die
Separation genutzt. Tonobjekt-basierte Verarbeitung ermöglicht es,
zusÀtzlich die NotenanfÀnge zu verfeinern, transiente Artefakte zu
reduzieren, gemeinsame Amplitudenmodulation (Common Amplitude Modulation
CAM) einzubeziehen und besser nichtharmonische Elemente der Töne
abzuschÀtzen. Der vorgestellte Algorithmus zur Quellentrennung von
Soloinstrument und Begleitung ermöglicht eine Echtzeitverarbeitung und ist
somit relevant fĂŒr den praktischen Einsatz.
Ein Experiment zur besseren Modellierung der ZusammenhÀnge zwischen
Magnitude, Phase und Feinfrequenz von isolierten Instrumententönen wurde
durchgefĂŒhrt. Als Ergebnis konnte die KontinuitĂ€t der zeitlichen
EinhĂŒllenden, die InharmonizitĂ€t bestimmter Musikinstrumente und die
Auswertung des Phasenfortschritts fĂŒr die vorgestellte Methode ausgenutzt
werden. ZusĂ€tzlich wurde ein Algorithmus fĂŒr die Quellentrennung in
perkussive und harmonische Signalanteile auf Basis des Phasenfortschritts
entwickelt. Dieser erreicht ein verbesserte perzeptuelle QualitÀt der
harmonischen und perkussiven Signale gegenĂŒber vergleichbaren Methoden nach
dem Stand der Technik.
Die vorgestellte Methode zur Klangquellentrennung in Soloinstrument und
Begleitung wurde zu den Evaluationskampagnen SiSEC 2011 und SiSEC 2013
eingereicht. Dort konnten vergleichbare Ergebnisse im Hinblick auf
perzeptuelle BewertungsmaĂe erzielt werden. Die QualitĂ€t eines
Referenzalgorithmus im Hinblick auf den in dieser Dissertation
beschriebenen Instrumentaldatensatz ĂŒbertroffen werden.
Als ein Anwendungsszenario fĂŒr die Klangquellentrennung in Solo und
Begleitung wurde ein Hörtest durchgefĂŒhrt, der die QualitĂ€tsanforderungen
an Quellentrennung im Kontext von Musiklernsoftware bewerten sollte. Die
Ergebnisse dieses Hörtests zeigen, dass die Solo- und Begleitspur gemĂ€Ă
unterschiedlicher QualitÀtskriterien getrennt werden sollten. Die
Musiklernsoftware Songs2See integriert die vorgestellte
Klangquellentrennung bereits in einer kommerziell erhÀltlichen Anwendung.This thesis addresses the development of a system for pitch-informed solo
and accompaniment separation capable of separating main instruments from
music accompaniment regardless of the musical genre of the track, or type
of music accompaniment. For the solo instrument, only pitched monophonic
instruments were considered in a single-channel scenario where no panning
or spatial location information is available.
In the proposed method, pitch information is used as an initial stage of a
sinusoidal modeling approach that attempts to estimate the spectral
information of the solo instrument from a given audio mixture. Instead of
estimating the solo instrument on a frame by frame basis, the proposed
method gathers information of tone objects to perform separation.
Tone-based processing allowed the inclusion of novel processing stages for
attack refinement, transient interference reduction, common amplitude
modulation (CAM) of tone objects, and for better estimation of non-harmonic
elements that can occur in musical instrument tones. The proposed solo and
accompaniment algorithm is an efficient method suitable for real-world
applications.
A study was conducted to better model magnitude, frequency, and phase of
isolated musical instrument tones. As a result of this study, temporal
envelope smoothness, inharmonicty of musical instruments, and phase
expectation were exploited in the proposed separation method. Additionally,
an algorithm for harmonic/percussive separation based on phase expectation
was proposed. The algorithm shows improved perceptual quality with respect
to state-of-the-art methods for harmonic/percussive separation.
The proposed solo and accompaniment method obtained perceptual quality
scores comparable to other state-of-the-art algorithms under the SiSEC 2011
and SiSEC 2013 campaigns, and outperformed the comparison algorithm on the
instrumental dataset described in this thesis.As a use-case of solo and
accompaniment separation, a listening test procedure was conducted to
assess separation quality requirements in the context of music education.
Results from the listening test showed that solo and accompaniment tracks
should be optimized differently to suit quality requirements of music
education. The Songs2See application was presented as commercial music
learning software which includes the proposed solo and accompaniment
separation method
Computer Models for Musical Instrument Identification
PhDA particular aspect in the perception of sound is concerned with what is commonly
termed as texture or timbre. From a perceptual perspective, timbre is what allows us
to distinguish sounds that have similar pitch and loudness. Indeed most people are
able to discern a piano tone from a violin tone or able to distinguish different voices
or singers.
This thesis deals with timbre modelling. Specifically, the formant theory of timbre
is the main theme throughout. This theory states that acoustic musical instrument
sounds can be characterised by their formant structures. Following this principle, the
central point of our approach is to propose a computer implementation for building
musical instrument identification and classification systems.
Although the main thrust of this thesis is to propose a coherent and unified
approach to the musical instrument identification problem, it is oriented towards the
development of algorithms that can be used in Music Information Retrieval (MIR)
frameworks. Drawing on research in speech processing, a complete supervised system
taking into account both physical and perceptual aspects of timbre is described.
The approach is composed of three distinct processing layers. Parametric models
that allow us to represent signals through mid-level physical and perceptual representations
are considered. Next, the use of the Line Spectrum Frequencies as spectral
envelope and formant descriptors is emphasised. Finally, the use of generative and
discriminative techniques for building instrument and database models is investigated.
Our system is evaluated under realistic recording conditions using databases of isolated
notes and melodic phrases
Music Information Retrieval Meets Music Education
This paper addresses the use of Music Information Retrieval (MIR) techniques in music education and their integration in learning software. A general overview of systems that are either commercially available or in research stage is presented. Furthermore, three well-known MIR methods used in music learning systems and their state-of-the-art are described: music transcription, solo and accompaniment track creation, and generation of performance instructions. As a representative example of a music learning system developed within the MIR community, the Songs2See software is outlined. Finally, challenges and directions for future research are described
How far away is plug 'n' play? Assessing the near-term potential of sonification and auditory display
The commercial music industry offers a broad range of plug 'n' play hardware and software scaled to music professionals and scaled to a broad consumer market. The principles of sound synthesis utilized in these products are relevant to application in virtual environments (VE). However, the closed architectures used in commercial music synthesizers are prohibitive to low-level control during real-time rendering, and the algorithms and sounds themselves are not standardized from product to product. To bring sound into VE requires a new generation of open architectures designed for human-controlled performance from interfaces embedded in immersive environments. This presentation addresses the state of the sonic arts in scientific computing and VE, analyzes research challenges facing sound computation, and offers suggestions regarding tools we might expect to become available during the next few years. A list of classes of audio functionality in VE includes sonification -- the use of sound to represent data from numerical models; 3D auditory display (spatialization and localization, also called externalization); navigation cues for positional orientation and for finding items or regions inside large spaces; voice recognition for controlling the computer; external communications between users in different spaces; and feedback to the user concerning his own actions or the state of the application interface. To effectively convey this considerable variety of signals, we apply principles of acoustic design to ensure the messages are neither confusing nor competing. We approach the design of auditory experience through a comprehensive structure for messages, and message interplay we refer to as an Automated Sound Environment. Our research addresses real-time sound synthesis, real-time signal processing and localization, interactive control of high-dimensional systems, and synchronization of sound and graphics
- âŠ