abstract: Two groups of cochlear implant (CI) listeners were tested for sound source localization and for speech recognition in complex listening environments. One group (n=11) wore bilateral CIs and, potentially, had access to interaural level difference (ILD) cues, but not interaural timing difference (ITD) cues. The second group (n=12) wore a single CI and had low-frequency, acoustic hearing in both the ear contralateral to the CI and in the implanted ear. These `hearing preservation' listeners, potentially, had access to ITD cues but not to ILD cues. At issue in this dissertation was the value of the two types of information about sound sources, ITDs and ILDs, for localization and for speech perception when speech and noise sources were separated in space. For Experiment 1, normal hearing (NH) listeners and the two groups of CI listeners were tested for sound source localization using a 13 loudspeaker array. For the NH listeners, the mean RMS error for localization was 7 degrees, for the bilateral CI listeners, 20 degrees, and for the hearing preservation listeners, 23 degrees. The scores for the two CI groups did not differ significantly. Thus, both CI groups showed equivalent, but poorer than normal, localization. This outcome using the filtered noise bands for the normal hearing listeners, suggests ILD and ITD cues can support equivalent levels of localization. For Experiment 2, the two groups of CI listeners were tested for speech recognition in noise when the noise sources and targets were spatially separated in a simulated `restaurant' environment and in two versions of a `cocktail party' environment. At issue was whether either CI group would show benefits from binaural hearing, i.e., better performance when the noise and targets were separated in space. Neither of the CI groups showed spatial release from masking. However, both groups showed a significant binaural advantage (a combination of squelch and summation), which also maintained separation of the target and noise, indicating the presence of some binaural processing or `unmasking' of speech in noise. Finally, localization ability in Experiment 1 was not correlated with binaural advantage in Experiment 2. / Dissertation/Thesis / Ph.D. Speech and Hearing Science 2013

La localisation des sources en azimuth repose sur le traitement des différences de temps d'arrivée des sons à chacune des oreilles: les différences interaurales de temps (``Interaural Time Differences'' (ITD)). Pour certaines espèces, il a été montré que cet indice dépendait du spectre du signal émis par la source. Pourtant, cette variation est souvent ignorée, les humains et les animaux étant supposés ne pas y être sensibles. Le but de cette thèse est d'étudier cette dépendance en utilisant des méthodes acoustiques, puis d'en explorer les conséquences tant au niveau électrophysiologique qu'au niveau de la psychophysique humaine. A la proximité de sphères rigides, le champ sonore est diffracté, ce qui donne lieu à des régimes de propagation de l'onde sonore différents selon la fréquence. En conséquence, quand la tête d'un animal est modélisée par une sphère rigide, l'ITD pour une position donnée dépend de la fréquence. Je montre que cet effet est reflété dans les indices humains en analysant des enregistrements acoustiques pour de nombreux sujets. De plus, j'explique cet effet à deux échelles: localement en fréquence, la variation de l'ITD donne lieu à différents délais interauraux dans l'enveloppe et la structure fine des signaux qui atteignent les oreilles. Deuxièmement, l'ITD de sons basses-fréquences est généralement plus grand que celui pour des sons hautes-fréquences venant de la même position. Dans une seconde partie, je discute l'état de l'art sur le système binaural sensible à l'ITD chez les mammifères. J'expose que l'hétérogénéité des réponses de ces neurones est prédite lorsque l'on fait l'hypothèse que les cellules encodent des ITDs variables avec la fréquence. De plus, je discute comment ces cellules peuvent être sensibles à une position dans l'espace, quel que soit le spectre du signal émis par la source. De manière générale, j'argumente que les données disponibles chez les mammifères sont en adéquation avec l'hypothèse de cellules sélectives à une position dans l'espace. Enfin, j'explore l'impact de la dépendance en fréquence de l'ITD sur le comportement humain, en utilisant des techniques psychoacoustiques. Les sujets doivent faire correspondre la position latérale de deux sons qui n'ont pas le même spectre. Les résultats suggèrent que les humains perçoivent des sons avec différents spectres à la même position lorsqu'ils ont des ITDs différents, comme prédit part des enregistrements acoustiques. De plus, cet effet est prédit par un modèle sphérique de la tête du sujet. En combinant des approches de différents domaines, je montre que le système binaural est remarquablement adapté aux indices disponibles dans son environnement. Cette stratégie de localisation des sources utilisée par les animaux peut être d'une grande inspiration dans le développement de systèmes robotiques. / Azimuth sound localization in many animals relies on the processing of differences in time-of-arrival of the low-frequency sounds at both ears: the interaural time differences (ITD). It was observed in some species that this cue depends on the spectrum of the signal emitted by the source. Yet, this variation is often discarded, as humans and animals are assumed to be insensitive to it. The purpose of this thesis is to assess this dependency using acoustical techniques, and explore the consequences of this additional complexity on the neurophysiology and psychophysics of sound localization. In the vicinity of rigid spheres, a sound field is diffracted, leading to frequency-dependent wave propagation regimes. Therefore, when the head is modeled as a rigid sphere, the ITD for a given position is a frequency-dependent quantity. I show that this is indeed reflected on human ITDs by studying acoustical recordings for a large number of human and animal subjects. Furthermore, I explain the effect of this variation at two scales. Locally in frequency the ITD introduces different envelope and fine structure delays in the signals reaching the ears. Second the ITD for low-frequency sounds is generally bigger than for high frequency sounds coming from the same position. In a second part, I introduce and discuss the current views on the binaural ITD-sensitive system in mammals. I expose that the heterogenous responses of such cells are well predicted when it is assumed that they are tuned to frequency-dependent ITDs. Furthermore, I discuss how those cells can be made to be tuned to a particular position in space irregardless of the frequency content of the stimulus. Overall, I argue that current data in mammals is consistent with the hypothesis that cells are tuned to a single position in space. Finally, I explore the impact of the frequency-dependence of ITD on human behavior, using psychoacoustical techniques. Subjects are asked to match the lateral position of sounds presented with different frequency content. Those results suggest that humans perceive sounds with different frequency contents at the same position provided that they have different ITDs, as predicted from acoustical data. The extent to which this occurs is well predicted by a spherical model of the head. Combining approaches from different fields, I show that the binaural system is remarkably adapted to the cues available in its environment. This processing strategy used by animals can be of great inspiration to the design of robotic systems.

This diploma thesis deals with a binaural hearing issues (it means hearing by both of ears), a human hearing ability to locate position of a sound source at three-dimensional space and parameters that affect this ability. In the second part, it focuses on psychoacoustic experiment, its main features and errors that can occur and which affect a results credibility. Method of pair comparisons is described more closely here. The last part of this thesis describes a technical solution of experiment in Java environment. The application should have a graphical interface and should be able to register a new user and perform a psychoacoustical experiment. The process of experiment is following. The aplication selects a random position of defined virtual sound source on the defined range and it plays this sound into headphones on button click. The users task is to set the application controls, representing a virtual sound source position, that way, where the user hear the sound come from. On another button click the application plays the same sound, but this sound comes from application controls set position (set by user). User compares this pair of sounds and modifies the position of second sound source until these two positions are same. The application stores these results for later processing on another button click. Principles of generating testing sound sources (sine wave, narrowband noise and sound file with wav extension) and their 3D positioning by measured head model impulse responses correlation are described thereinafter. An ability of human hearing system to locate a virtual sound source in dependence on sound parameters is discussed in conclusion.

Binaural sound reproduction is most commonly made with headphones, although little research has been dedicated towards evaluating the sound of binaural for headphones reproduced on loudspeakers, which is the purpose of this thesis. An experimental quantitative method was designed in order to measure the objective effect of binaural processing both on headphones and loudspeakers so that they could be compared. Sine sweeps covering the entire audible frequency spectrum were processed with an ambisonics spatializer at different azimuth and distance parameters and then downmixed to binaural. The same source signal was also panned with a traditional equal-power panning law. Both was played back through headphones and loudspeakers then recorded with a dummy head. The recordings were deconvolved into graphs displaying their frequency responses. The results show that binaural sound produce different spectral distortion depending on the panning position on both headphones and loudspeakers, although additional subjective evaluation such as listening tests are required to determine the actual usefulness of binaural sound through loudspeakers.

The research investigates the transposition of circus performance to the aural and sonic realm asking the question:  How and can circus exist in and through sound?

Exponering till Binaurala Svävningar (BinSv) kan enligt tidigare forskning orsaka ändringar i vårt sinnestillstånd. Hittills har BinSv använts exklusivt i avslappnings- och meditationsmusik men hur kan BinSv användas som ett ramverk inom populärmusik, och hur uppfattas det? Denna studietillämpar forskning genom design metodiken för att redogöra för hur man kan applicera BinSv påolika sätt i skapande av populärmusik och undersöka i kvalitativa semistrukturerade intervjuer hurdetta uppfattas. I resultatet redovisas 3 olika sätt att applicera BinSv-frekvenser: på en basgitarr, påen tillagd statisk sinuston och på en sinuston som följer grundtonen i musiken. Deltagarna i undersökningen har uttryckt utökad avslappning och upprymdhet efter att ha lyssnat på musiken. Vidare diskuteras olika affordanser som BinSv kan erbjuda båda musikskaparen och lyssnaren.

Background: Binaural hearing improves our ability to understand speech and to localize sounds. Hearing loss can interfere with binaural cues, and despite the success of amplification, ∼25% of people with bilateral hearing loss fit with two hearing aids choose to wear only one (e.g., Brooks and Bulmer, 1981). One explanation is reduced binaural processing, which occurs when the signal presented to one ear interferes with the perception of the signal presented to the other ear (e.g., Jerger et al, 1993). Typical clinical measures, however, are insensitive to binaural processing deficits. Purpose: The purpose of this study was to determine the extent to which behavioral measures of binaural performance were related to electrophysiological measures of binaural processing in subjects with symmetrical pure-tone sensitivity. Research Design: The relationship between middle latency responses (MLRs) and behavioral performance on binaural listening tasks was assessed by Spearman's rho correlation analyses. Separate repeated measures analyses of variance (RMANOVAs) were performed for MLR latency and MLR amplitude. Study Sample: Nineteen subjects were recruited for the present study based on a clinical presentation of symmetrical pure-tone sensitivity with asymmetrical performance on a word-recognition in noise test. This subpopulation of patients included both subjects with and subjects without hearing loss. Data Collection and Analysis: Monaural and binaural auditory processing was measured behaviorally and electrophysiologically in right-handed subjects. The behavioral tests included the Words-in-Noise test (WIN), the dichotic digits test (DDT), and the 500 Hz masking level difference (MLD). Electrophysiologic responses were measured by the binaural interaction component (BIC) of the MLR. The electrophysiological responses were analyzed to examine the effects of peak (Na, Pa, and Nb) and condition (monaural left, monaural right, binaural, and BIC) on MLR amplitude and latency. Results: Significant correlations were found among electrophysiological measures of binaural hearing and behavioral tests of binaural hearing. A strong correlation between the MLD and the binaural Na-Pa amplitude was found (r =.816). Conclusions: The behavioral and electrophysiological measures used in the present study clearly showed evidence of reduced binaural processing in ∼10 of the subjects in the present study who had symmetrical pure-tone sensitivity. These results underscore the importance of understanding binauralauditory processing and how these measures may or may not identify functional auditory problems.

Ce travail s'inscrit dans le contexte de la localisation de source sonore depuis un capteur binaural (constitué de deux microphones placés sur un élément diffusant) doté de mobilité. Un schéma de localisation "active" en trois phases est considéré : (a) estimation de primitives spatiales par une analyse court-terme du flux audio ; (b) localisation audio-motrice par assimilation de ces données et combinaison avec les ordres moteurs du capteur au sein d'un schéma d'estimation stochastique ; (c) commande en boucle fermée du mouvement du capteur de façon à améliorer la qualité de la localisation. Les recherches portent sur la définition de stratégies de "mouvement actif" constituant la phase (c). Le problème est formulé comme la maximisation d'un critère d'information défini à partir des lois de filtrage de la position relative capteur-source sur un horizon temporel glissant dans le futur (plus exactement de son espérance sur les observations qui seront assimilées sur cet horizon conditionnellement aux observations passées). Cet horizon peut être constitué du prochain instant ou des N prochains instants, ce qui donne lieu à une stratégie "one-step-ahead" ou "N-step-ahead", respectivement. Une approximation de ce critère par utilisation de la transformée "unscented" et le calcul automatique du gradient de celle-ci par exploitation des nombres duaux, permettent la détermination de la commande (en boucle fermée sur l'audio donc) à appliquer au capteur. Les résultats ont été validés par des simulations réalistes, et, pour certains, par des expérimentations sur un ensemble tête-torse anthropomorphe doté de perception binaurale et de mobilité. / This work takes place within the field of sound source localization from a binaural sensor (consisting of two microphones placed on a diffusing element) endowed with mobility. An "active" three-phase localization scheme is considered: (a) estimation of spatial primitives by a short-term analysis of the audio stream; (B) audio-motor localizatio! n by assimilation of these data and combination with the! motor commands of the sensor within a stochastic estimation scheme; (C) closed-loop control of the movement of the sensor in order to improve the quality of the location. The research focuses on the definition of "active motion" strategies constituting phase (c). The problem is formulated as the maximization over a receding horizon of an information criterion defined from the filtering pdfs of the relative sensor-to-source position (more exactly of the maximization of its expectation on the N observations that will be assimilated on this horizon conditionally to the past observations). This horizon can consist of the next time instant or the next N time instants, what gives rise to a "one-step-ahead" or "N-step-ahead" strategy, respectively. An approximation of this criterion by using the unscented transform and the automatic calculation of its gradient by using the dual numbers allow the determination of the control (therefore, in closed loop on the audio) to be applied to the sensor. The results were validated by realistic simulations and, for some of them, by experiments on an anthropomorphic head-and-torso simulator endowed with binaural perception and mobility.

No description available.

De senaste åren har surround-formatet Dolby Atmos blivit allt mer populärt inom musikproduktion. Musikproducenter och mixare världen över har börjat inse de möjligheter och fördelar som Dolby Atmos kan bidra med till ens egna producerande och mixande. Många artister och band väljer nu även att göra mixar i Dolby Atmos av sin redan befintliga stereo-katalog. Vissa utnyttjar formatet mer extremt och panorerar ljud åt alla olika håll och kanter i rummet medan andra använder formatet mer subtilt och kanske endast strävar efter en bredare stereo-upplevelse. Hur skulle det låta om jag mixade om två av mina låtar i Dolby Atmos, låtar som jag redan producerat och mixat i stereo? Kan spatialt ljud ge min musik nytt liv och förhöja den musikaliska upplevelsen? Denna text fokuserar kring mitt utforskande och min upplevda process av att mixa i Dolby Atmos. Syftet med projektet är att utforska produktion och mixning i Dolby Atmos för att således erhålla mer erfarenhet och kunskap som producent och mixare. Ett delsyfte är även att undersöka skillnader inom arbetsmetoder från att mixa i stereo kontra att mixa i Dolby Atmos och på ett djupare plan skaffa mig en större insikt i hur den upplevda surround-känslan i Dolby Atmos kan upplevas av min egenproducerade musik både för mig personligen och för utomstående parter. Projektet avslutas med ett genomförande av ett lyssningstest där jag bjuder in lyssningsdeltagare för att lyssna på och jämföra stereo-versionen med Dolby Atmos-versionen. Dagbok och anteckningar i min smartphone har förts under processens gång samt ljudupptagning av intervjuerna från lyssningstestet. Undersökningen mynnar ut till resultat och avslutande diskussion där jag jämför stereo och Dolby Atmos med varandra och kommer fram till att formaten erbjuder sina egna förmåner och fördelar till att mixa musik. Undersökningen avslutas med förslag till framtida forskning inom området.