Denna uppsats faller inom ämnesområdet ljud-&musikproduktion och studiens syfte är att bidra med en djupare förståelse för hur dagens lyssnare upplever binaurala egenskaper i musik. Tidigare forskning föreslår att introducera framtida lyssnare till binaural musik genom så kallade hybridmixar, vanliga stereomixar med vissa binaurala egenskaper. Metodiskt utfördes ett lyssningstest där 15 ljudutbildade personer fick jämföra två låtar, båda mixade i stereo och binauralt. För den första låten applicerades en helt binaural strategi medans den andra låten mixades som en hybridmix. Resultaten visade på att en helt binauralt mixad låt mest bidrog med förvirring och inte var att föredra över en vanlig stereomix. Dock visade sig en blandning av stereo- och binaurala egenskaper i hybridmixen vara något som lyssnarna föredrog över vanlig stereomix då det tillförde något extra och spännande. Sammanfattningsvis tyder resultaten på att hybridmixad musik är något som lyssnarna upplever både nytt och spännande, vilket skulle kunna vara det första steget mot helt binaural musik.

Tese de mestrado. Multimédia (Música Interactiva e Design de Som). Universidade do Porto. Faculdade de Engenharia. 2011

<p>Syftet med denna studie var att undersöka effekten av Bani, som representant för Binaural Beat-teknologi, på stress. Som delsyfte undersöktes även ångest och depressivitet. Samplet utgjordes av 27 universitetsstuderande på Örebro universitet. Binaural Beats är ljudfrekvenser med vilka hjärnans EEG sägs synkroniseras och kan påverka medvetandetillståndet. Genom en experimentell design med</p><p>upprepade mätningar och en kontrollgrupp undersöktes</p><p>förändringar i stress, ångest och depressivitet under fyra veckors lyssnande av Bani. Signifikanta effekter över tid påträffades gällande psykisk stress och depressivitet för interventionsgruppen. Vissa gruppskillnader påträffades även för ångest och fysisk stress, vilka dock verkade vara av mer naturligt fluktuerande karaktär. Resultaten indikerade att Bani har en lindrande effekt på psykisk stress och depressivitet.</p><p>Nyckelord. Binaural Beats, stress, hjärnsynkronisering, Bani,</p><p>ångest, depressivitet.</p> / <p>The purpose of this study was to investigate the effect of Bani, as a representative of Binaural Beat technology, on stress. As a secondary purpose anxiety and depression were examined. The sample consisted of 27 university students at the Örebro University. Binaural Beats are sound frequencies with which the brain is said to synchronize and can</p><p>affect states of conciousness. Changes in stress, anxiety and depression were examined through an experimental design with repeated measures and a control group for a period of four weeks of listening to Bani. Significant effects were found over time concerning psychological stress and depression for the intervention group. Some group differences were</p><p>also found for anxiety and physiological stress, although they seemed to be more affected by natural fluctuations. The results indicated that Bani has a decreasing effect on psychological stress and depression.</p><p>Keywords: Binaural Beats, stress, brainwave synchronization, Bani, anxiety, depression.</p>

Syftet med denna studie var att undersöka effekten av Bani, som representant för Binaural Beat-teknologi, på stress. Som delsyfte undersöktes även ångest och depressivitet. Samplet utgjordes av 27 universitetsstuderande på Örebro universitet. Binaural Beats är ljudfrekvenser med vilka hjärnans EEG sägs synkroniseras och kan påverka medvetandetillståndet. Genom en experimentell design med upprepade mätningar och en kontrollgrupp undersöktes förändringar i stress, ångest och depressivitet under fyra veckors lyssnande av Bani. Signifikanta effekter över tid påträffades gällande psykisk stress och depressivitet för interventionsgruppen. Vissa gruppskillnader påträffades även för ångest och fysisk stress, vilka dock verkade vara av mer naturligt fluktuerande karaktär. Resultaten indikerade att Bani har en lindrande effekt på psykisk stress och depressivitet. Nyckelord. Binaural Beats, stress, hjärnsynkronisering, Bani, ångest, depressivitet. / The purpose of this study was to investigate the effect of Bani, as a representative of Binaural Beat technology, on stress. As a secondary purpose anxiety and depression were examined. The sample consisted of 27 university students at the Örebro University. Binaural Beats are sound frequencies with which the brain is said to synchronize and can affect states of conciousness. Changes in stress, anxiety and depression were examined through an experimental design with repeated measures and a control group for a period of four weeks of listening to Bani. Significant effects were found over time concerning psychological stress and depression for the intervention group. Some group differences were also found for anxiety and physiological stress, although they seemed to be more affected by natural fluctuations. The results indicated that Bani has a decreasing effect on psychological stress and depression. Keywords: Binaural Beats, stress, brainwave synchronization, Bani, anxiety, depression.

The most accepted model of mammalian binaural sound localization postulates two neural/perceptual channels with hemifield tuning and overlapping medial borders; the extent to which the two channels are co-activated by the source is the neural "code" for the source's azimuthal location. This model does not take into account physiological data on the existence of a population of cells with spatial receptive fields centered on the azimuthal midline. The following work sought to test the hypothesis that the mammalian binaural sound localization apparatus includes a third, midline-tuned channel. Ten experiments used a selective adaptation paradigm in human listeners to probe for the existence of a midline channel. Psychometric functions were obtained for lateral position based on ITD or ILD both before and after adaptation with high-frequency (2800 and 4200 Hz) or low-frequency (260 and 570 Hz) tones. Listeners experienced highly lateralized adaptor stimuli with different frequencies at each ear (asymmetrical adaptation), highly lateralized adaptor stimuli of the same frequency at each ear (symmetrical adaptation), and single frequency adaptation at the midline (central adaptation). At both high and low frequencies in the domains of both interaural time difference (ITD) and interaural level difference (ILD), location judgements after asymmetrical adaptation shifted away from the fatigued side. These shifts occurred across each adapted hemifield and extended slightly over the midline, as is consistent with the two-channel model. The two-channel model would predict no effect of symmetrical or central adaptation because fatiguing both lateral channels equally would not change their relative activation by a given source. In practice, the result of symmetrical adaptation was a shift in location judgements towards the midline as would be expected if adaptation of the lateral channels resulted in a greater relative contribution of a third, midline channel. Likewise, central adaptation tended to result in shifts in perceived location towards the sides. The evidence for the midline channel was strong for high and low frequencies localized by ILD, and was present for low frequencies, but not for high frequencies, localized by ITD.

A new objective measurement system to predict speech intelligibility in binaural listening conditions is proposed for use with nonlinear hearing devices. Digital processing inside such devices often involves nonlinear operations such as clipping, compression, and noise reduction algorithms. Standard objective measures such as the Articulation Indeix (AI), the Speech Intelligibility Index (SII) and the Speech Transmission Index (STI) have been developed for monaural listening. Binaural extensions of these measures have been proposed in the literature, essentially consisting of a binaural pre-processing stage followed by monaural intelligibility prediction using the better ear or the binaurally enhanced signal. In this work, a three-stage extension of the binaural SII approach is proposed that deals with nonlinear acoustic input signals. The reference-based model operates as follows: (1) a stage to deal with nonlinear processing based on a signal-separation model to recover estimates of speech, noise and distortion signals at the output of hearing devices; (2) a binaural processing stage using the Equalization-Cancellation (EC) model; and (3) a stage for intelligibility prediction using the SII or the short-time Extended SII (ESII). Multiple versions of the model have been developed and tested for use with hearing devices. A software simulator is used to perform hearing-device processing under various binaural listening conditions. Details of the modeling procedure are discussed along with an experimental framework for collecting subjective intelligibility data. In the absence of hearing-device processing, the model successfully predicts speech intelligibility in all spatial configurations considered. Varying levels of success were obtained using two simple distortion modeling approaches with different distortion mechanisms. Future refinements to the model are proposed based on the results discussed in this work.

In binaural hearing aids, several beamforming algorithms can be used. These beamformers aim to enhance the target speech signal and preserve the binaural cues of the target source (e.g. with constraints on the target). However, the binaural cues of the other directional sources as well the background noise are often lost after processing. This affects the global impression of the acoustic scene, and it limits the perceptual separation of the sources by the hearing aids users. To help the hearing aids users to localize all the sound sources, it is important to keep the binaural cues of all directional sources and the background noise. Therefore, this work is devoted to find the best trade-off between the noise/interferers reduction and the cues preservations not only for the directional interferers but also for the background noise based on selection and mixing processes. In this thesis, some classification decision algorithms, which are based on different criteria such as the power, the power difference, and the coherence, are proposed to complete the selection and mixing processes. Simulations are completed using recorded signals provided by a hearing aid manufacturer to validate the performance of the proposed algorithm under different realistic acoustic scenarios. After detailed testing using different complex acoustic scenarios and different beamforming configurations, the results indicate that some of the proposed classification decision algorithms show good promise, in particular the classification decision algorithm based on coherence.

The video game industry is experiencing tremendous growth and developing games that stand out against the competition requires ever increasing production budgets. Graphics have been a selling point for video games for a long time, resulting in huge technical advancements in visuals. Audio has received more attention during the recent years, both in terms of sound-design and technical developments. This study compared two alternatives for spatializing audio over headphones in a game setting, while also comparing them against a more traditional stereo output. A commercial game was used to provide the game setting and participants rated the three different outputs based on three attributes and described their experience using Microsoft Product Reaction Cards. No statistically significant differences were found between the three outputs in any of the six rated attributes when doing a paired t-test or a Wilcoxon Signed-Rank Test. Further analysis of frequency content, participants’ comments and Microsoft Product Reaction Cards were done to find out what sets the spatializing alternatives and stereo apart from each other.

Detta arbete syftar till att undersöka hur binauralt ljud upplevs i avseende till spelares förmåga att lokalisera ljudkällor i olika våningsplan i digitala spel i jämförelse med stereoljud. Arbetet kopplas till tidigare forskning inom ljudteknik i digitala spel. För att undersöka frågeställningen har en artefakt skapats i form av en digital miljö där målet är att lokalisera ljudkällor i olika våningsplan. Artefakten är skapad i två versioner, där den ena versionen använder binauralt ljud och den andra använder stereoljud. Arbetet har använt kvantitativa och kvalitativa metoder. Resultatet av dessa analyseras och jämförs för att utröna vilken teknik som lämpas bäst för ljudlokalisering i digitala spel.

Första gången jag upplevde musik i Dolby Atmos blev jag helt såld. Ljudupplevelsen var något jag aldrig tidigare varit med om i en studio. Ljuden omslöt mig från alla håll och när jag slöt mina ögon förvandlades rummet till en annan plats. Jag var där. I epicentret av musiken. Min drivkraft har sedan dess varit att bemästra formatet till den grad att jag kan utveckla mitt konstnärliga material i formatet. Efter att ha producerat och mixat musik i stereo i många år, var jag nyfiken på vad Atmos kunde bidra med till min egen konstnärliga utveckling. Tillsammans med Dolby Laboratories som extern partner har detta konstnärliga projekt utgått från frågorna; Vilket mervärde ger Dolby Atmos till mig som musikproducent? Hur skiljer sig mina artistiska val i jämförelse med stereo-produktion? Kommer min spatiala lyssningsförmåga att bli påverkad och hur formas mina mixningskonventioner? Det konstnärliga materialet som framtogs under projektets gång formades genom en processinriktad metodik och resulterade i fem låtar som vävdes ihop till en svit. Insikter och lärdomar presenteras löpande genom texten genom analysering av dokumentation från skriftliga anteckningar, samtal med Dolby Laboratories, diskussion med kollegor samt skärminspelningar från skapandeprocessen.