Characteristics of heating, ventilation, air conditioning and refrigeration (HVAC&R) equipment sounds and people's responses to them were studied in order to develop models to predict annoyance from recordings of the sound. These models are intended to address shortcomings of currently used methods for HVAC&R product sound assessment. Coupled with sound prediction models, the annoyance models will be used to monitor and guide improvements to HVAC&R equipment sound quality throughout the product design process: from virtual early design, through to the prototyping and product refinement stages. Responses to residential and refrigerated truck product noise was studied; both produce broadband random noise and families of harmonics related to rotating and reciprocating components within the system. Tests were conducted to determine how people describe HVAC&R equipment sounds; how their descriptions relate to sound characteristics and overall assessments; and to develop models that relate predicted strengths of sound characteristics to the overall assessment. Annoyance models were developed for each types of product. Loudness and spectral balance metrics are included in models for both types of product. Inclusion of a tonalness metric improved models for residential units, and roughness and impulsiveness metrics improved models for refrigerated truck units. The models developed were used to predict responses in the other tests and there was good agreement between predicted and measured responses. An illustration of the use of the annoyance models, in conjunction with sound visualization and signal modification techniques, to guide improvements to product sound quality is given.

Sonification is the systematic transformation of data to sound. Sonification is a means to communicate information, to support navigation, or to explore data. In a multi-disciplinary research project we develop a psychoacoustically-motivated sonification that supports surgeons’ orientation in image-guided interventions. One drawback of image-guidance is that neither the location of monitors nor the displayed view on the patient’s anatomy coincides with the actual viewpoint of the surgeon. Surgeons need to mentally scale, rotate, and translate the displayed graphics. These operations are cognitively demanding. Sonification can reduce cognitive load and relieve the visual channel to improve the ergonomic situation in the operating room by communicating the location of the target, relative to the tool tip, like the center of a tumor relative to the ablation needle. By means of psychoacoustic sonification we ensure that the sounds are readily interpretable in terms of orthogonal and linear dimensions with a high resolution.

There are many facets that influence the quality of a musical theatre production. The visual appeal is created from the décor, costumes and lighting, whereas the plot, pace, and relationship a listener develops with the characters are fundamental to the performance quality. However, one often overlooked factor is the impact of sound quality. The perception of sound quality is subjective but is greatly impacted by the environment in which the listener finds themselves. If the projection of the music is underwhelming in depth and expression, or the balance of the dynamics and timbre are badly mixed, this can jeopardise the production’s success, regardless of the quality of the composition or the visual aspects. The production budget for a musical performance can be prohibitive. As a result, prerecorded music is often used as an alternative substitute to live musicians. However, the subjective authenticity of a musical may be jeopardized by the exclusion of live musicians and create additional challenges and performance limitations. One such challenge is the environment in which music will be played. Recorded music is usually created in a single format such as compact disc or for broadcasting, and the cost of recording be can just as expensive as a live performance, especially on large scale works. Time and budget constraints may impact the sound quality. In addition to this, the varying acoustic properties of potential venues may emphasise sonic gaps and flaws contributing to a listener’s negative perception of the sound quality, resulting in a compromised experience of the performance as a whole. This mixed method dissertation offers a systematic explanation to potentially resolve these challenges and limitations by conceptualising established knowledge of sound, audio and acoustics to formulate a framework for adaptive sound. These concepts are put into practice by creating a specifically designed audio recording that is experimented with in multiple theatre scenarios to successfully achieve optimal adaptation of the sound for the theatre environment. / Dissertation (MMus)--University of Pretoria, 2019. / Music / MMus / Unrestricted

Predictors of people’s responses to noise inside cars are used by car companies to identify and address potential noise problems from tests. Because significant advances have been made in the reduction of engine, powertrain, and tire/road noise, it is now important to pursue reductions in wind or aerodynamic noise. While models of loudness are commonly used to predict people’s responses to stationary wind noise, some wind noises are less acceptable than is predicted by the loudness metric. Additional sound characteristics may account for this. The research described in this dissertation was conducted in two main stages. The focus of the first stage was on improving acceptability predictions for stationary noise, by using additional sound quality metrics along with predictions of loudness. Three listening studies were designed and conducted, including one study with aspiration noise. Test sounds were a combination of recordings made on cars in a wind tunnel and modified recordings. Methods to modify individual sound characteristics were developed to de-correlate metrics across the set of test sounds, and to examine trends of acceptability with particular sound characteristics. Models of acceptability for stationary wind noise are significantly improved when a metric that predicts the sharpness of a sound is included in the model with the loudness metric. The focus of the second stage of the research was on improving acceptability predictions for non-stationary noise, particularly noise with the kind of variations that are expected from wind gusts. A simulation method was developed to generate sounds with controlled gusting features by modifying stationary noise recordings. Two listening studies were conducted containing simulated gusting sounds, and a gusting unacceptability metric was designed to predict subjects’ responses based on the strength, modulation rate, and duration of the gusts. The inclusion of this gusting metric significantly improved the goodness of fit of linear and logistic models of non-stationary noise acceptability containing Loudness and Sharpness.

The human auditory system can become an active agent in the production of sound when stimulated with specific tone combinations. The resulting auditory distortion products can be amplified and drawn attention to by employing certain just intonation practices – a compositional technique that may serve as a powerful catalyst for reaching different states of mind in listeners. In this thesis, those psychoacoustic phenomena critical to the act of tuning are explored. An experiential tuning protocol is introduced and supported by insights from physiology and neuroscience research. Based on the tuneability of musical intervals, a harmonic framework involving harmonic and subharmonic relationships is analyzed and exemplified via the accompanying composition XV XXVII III XXI IX: Variations. From a phenomenological perspective, the research extends to broader contexts, investigating potential social, ethical, cultural, and political implications of such a practice. / <p><em>XV XXVII III XXI IX: Variations</em> by Luka Aron is a work in 5 parts in which a selected acoustic instrumentation, consisting of bass clarinet, contrabass, euphonium, foghorn organ, harpsichord, serpent, shō, and trumpet coalesces with analog as well as digital synthesis, into one unified mass of sound. By tuning sustained tones towards precision upon occupying the same pitch space, the various timbresare as much canceled out as reinforced, resulting in flux states of spectral fusion. This effect is further achieved through traversing a labyrinth of multiple closely related overtone series, serving as a harmonic framework for the piece’s ever-shifting bedrock. A careful selection of partials is presented, stimulating additional tones in the perception of the listener, making use of a psychoacoustic phenomenon, commonly referred to as otoacoustic emissions, or combination tones. Heavy distortion is then applied to the source signal, allowing the combination tones to materialize in the physical space. Through this, a secondary structure (that, in fact, exposes theundertone series) is gradually unveiled: like light rays meeting the surface of water, partially reflecting back to air, and refracting at once, as they pass from one medium to the other. On a structural plane, the piece stems from complex multi-layered golden mean relationships that permeate to all levels of the composition, ranging from the overall arc to the formal as well as rhythmical aspects of each individual variation, where every sound event is spiraling out of the previous one, and the endpoint is determined right at the initial stroke, before ever unfolding over the total playtime of 43 minutes. With Aron operating the Buchla 200 and EMS VCS3 synthesizers, in addition to the SuperCollider andPure Data coding environments, the cast of musicians includes an array of Stockholm-based artists, such as Mattias Hållsten on shō–a japanese mouth organ–and Susana Santos Silva on trumpet (both members of CC Hennix’ Kamigaku ensemble), just intonation contrabassist Vilhelm Bromander, along with Amina Hocine and her unique self-built foghorn organ. Frequent collaborators Fabian Willmann on bass clarinet and Raphaël Rossé on serpent and euphonium join from the electroacoustic group MINUA, which Aron co-founded. For this occasion, the piece will be diffused on an arrangement of 31 speakers.</p><p><strong>Den klingande delen är arkiverad.</strong></p><p><strong>Luka Aron är artistnam för Luca Aaron Pusch.</strong></p>

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The subject of the thesis was proposed by the acoustic consultancy firm Brekke &amp; Strand, which is of relevance for their additional understanding and development of services and contribution to robust solutions. The aim with this thesis is to give indicative results and to dig deeper into the relation between environmental noise and the perception of the same, specially focusing on construction related noise but also permanent noise sources that originates from infrastructure. The area of interest to evaluate the study is a central location in Stockholm, specifically around Slussen.The importance of a study within this field is vital, especially when considering possible negative health effects that can be related to the perceived noise exposure. With that background it is worth to consider the amount of healthy-life-years lost in Europe each year, which is assumed to be one million. The correlation between lost life years and noise is one of many, but it is also proven to be a catalyst when it comes to stress related or cardiovascular diseases. For instance, if one is living closer than 50 meters from a major road the risk can be four times higher to be annoyed, which in extension can be coupled to the diseases mentioned above.The practical implementation of the study is conducted with a survey and field measurements, with a psychoacoustical perspective and within the frames of a case-control study. Partially this includes to inform the participants of the study at different stages regarding construction noise. The provided information, survey and field measurements aims to be a substantial part of the evaluation regarding the perceived noise whether it is due to construction work, infrastructure or other stochastic sources.The result is presented and distinguished based on distance to noise source, differentiated by gender as well as which type of source that tends to be most annoying. The implemented ranking is displayed as the ICBEN score of each category or source which aims to measure the perceived impact. Even though the results are indicative, the conclusion yields an information dependency as well as a noise source dependency. Further on, the result yields an interesting pattern between genders where women tend to be more disturbed by construction- and other-noise, whereas men tend to be more disturbed by rail- and road-noise. / Ämnet för uppsatsen föreslogs av akustiskkonsultföretaget Brekke &amp; Strand, vilket är av relevans för deras ytterligare förståelse och utveckling av tjänster och bidrag till robusta lösningar. Syftet är att ge vägledande resultat och gräva djupare i förhållandet mellan samhällsbuller och uppfattningen av detsamma, med särskilt fokus på konstruktionsrelaterat buller men också permanenta bullerkällor som härstammar från infrastruktur. Studien och utvärderingen av den samma har fokuserats till Slussenområdet i centrala Stockholm.Betydelsen av en studie inom detta område är avgörande, särskilt när man överväger eventuella negativa hälsoeffekter som kan relateras till den upplevda bullerexponeringen. Med den bakgrunden är det värt att ta hänsyn till hur många hälsosamma levnadsår som går förlorade i Europa varje år, vilket antas vara en miljon. Korrelationen mellan förlorade levnadsår och buller är en av många, men det har också visat sig vara en katalysator när det gäller stressrelaterade eller hjärt- och kärlsjukdomar. Om man till exempel bor närmare än 50 meter från en huvudväg kan risken vara fyra gånger högre för att bli störd och påverkad av buller, vilket i förlängning kan kopplas till ovan nämnda sjukdomar.Det praktiska genomförandet av studien utförsmed en enkätundersökning, fältmätningar,med ett psyko-akustiskt perspektiv och inom ramen för en fallkontrollstudie. Detta inkluderar delvis att informera deltagarna i studien i olika stadier beträffande konstruktionsrelaterat buller. Den tillhandahållna informationen, undersökningen och fältmätningarna syftar till att vara en väsentlig del av utvärderingen av det upplevda bullret oavsett om det beror på byggnadsarbete, infrastruktur eller andra stokastiska källor.Resultatet presenteras och skiljer sig utifrån avstånd till bullerkälla, uppdelat efter kön samt vilken typ av källa som tenderar att vara mest irriterande. Den implementerade rangordningen visas som ICBEN-skalan för varje kategori eller källa, som syftar till att mäta den upplevda effekten. Även om resultaten är vägledande så visar resultaten ett informationsberoende samt ett bullerkällaberoende. Vidare ger resultatet ett intressant mönster mellan könen, där kvinnor tenderar att bli mer störda av konstruktions- och andra-bullerkällor, medan män tenderar att bli mer störda av järnvägs- och väg-buller.

<p>This Master’s thesis presents results from two clinical hearing aid studies. Wide dynamic range compression (WDRC), a hearing aid amplification algorithm widely used in the hearing aid industry, is compared against a novel hearing aid called the Neuro-Compensator (NC), which employs a neural-based amplification algorithm based on a computational model of the auditory periphery. The NC strategy involves preprocessing an incoming auditory signal, such that when the signal is presented to a damaged cochlea, auditory nerve output is reconstructed to look similar to the auditory nerve output of a healthy cochlea for the original auditory signal. The NC and WDRC hearing aid technologies are compared across a multitude of auditory domains. Objective measures of speech intelligibility in quiet and in noise, music perception, sound localization, and subjective measures of sound quality are obtained. It was hypothesized that the NC would restore more normal auditory abilities across auditory domains, due to its proposed strategy of restoring more normal auditory nerve output. Results from the clinical hearing aid studies quantified domains in which the NC was superior to WDRC, and vice versa.</p> / Master of Science (MSc)

<p>Hearing loss afflicts as many as 10\% of our population.Fortunately, technologies designed to alleviate the effects ofhearing loss are improving rapidly, including cochlear implantsand the increasing computing power of digital hearing aids. Thisthesis focuses on theoretically sound methods for improvinghearing aid technology. The main contributions are documented inthree research articles, which treat two separate topics:modelling of human speech recognition (Papers A and B) andoptimization of diagnostic methods for hearing loss (Paper C).Papers A and B present a hidden Markov model-based framework forsimulating speech recognition in noisy conditions using auditorymodels and signal detection theory. In Paper A, a model of normaland impaired hearing is employed, in which a subject's pure-tonehearing thresholds are used to adapt the model to the individual.In Paper B, the framework is modified to simulate hearing with acochlear implant (CI). Two models of hearing with CI arepresented: a simple, functional model and a biologically inspiredmodel. The models are adapted to the individual CI user bysimulating a spectral discrimination test. The framework canestimate speech recognition ability for a given hearing impairmentor cochlear implant user. This estimate could potentially be usedto optimize hearing aid settings.Paper C presents a novel method for sequentially choosing thesound level and frequency for pure-tone audiometry. A Gaussianmixture model (GMM) is used to represent the probabilitydistribution of hearing thresholds at 8 frequencies. The GMM isfitted to over 100,000 hearing thresholds from a clinicaldatabase. After each response, the GMM is updated using Bayesianinference. The sound level and frequency are chosen so as tomaximize a predefined objective function, such as the entropy ofthe probability distribution. It is found through simulation thatan average of 48 tone presentations are needed to achieve the sameaccuracy as the standard method, which requires an average of 135presentations.</p>