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Στην παρούσα διπλωματική εργασία πραγματοποιείται ένα ψυχοακουστικό test για την μελέτη διαφορετικών τρόπων ισοστάθμισης και τοποθέτησης των ακουστικών για διαφορετικούς χώρους. Μελετάται η υποκειμενική επίδραση τριών παραμέτρων, αυτών της απόστασης, της αντήχησης και της ποιότητας για κάθε διαφορετική τοποθέτηση και δωμάτιο. Σε αυτό το πλαίσιο αναλύονται τα αποτελέσματα και συγκρίνονται με βάση αυτά που έχουν ήδη πραγματοποιηθεί σε διάφορες μελέτες. / --

A tier 1 automotive components supplier has developed a virtual user interface system for the purpose of replacing currently existing physical buttons mounted on automotive steering wheels. The system is capable of generating acoustic and vibratory feedback to the user for the purpose of mimicking the sound and feel of mechanical buttons. The work performed in this thesis served to investigate what the input waveform should be to the system in order to generate a desired audio output signal. Additionally, subjective testing in the form of a sound jury was conducted in order to identify which types of sounds should be associated with which command functions in order to indicate successful initiation of the intended function. A model for grouping command functions into banks, where each bank is assigned a single sound, was then developed for the purpose of reducing the total number of button sounds used in an automotive environment.

<p>This survey tries to find out if and how we can be influenced of extreme low and strong frequencies in the area 0-40 Hz. A group of 52 teachers/musicstudents and non musicstudents was trying to assess what they thought, experiences and tried to describe why they thought as they did, when they listen on three different versions of same musical piece. Without low frequent bass, original and strengthened bass, randomly mixed. Several different musical pieces was used in same survey. The work also makes a commitment to theories about the people's hearing and the will of ‘selfmotion’. The result gives a hint that participators in the survey prefer to listen to music on “balance”, rather then music with reinforced low bassfrequencies.</p>

This survey tries to find out if and how we can be influenced of extreme low and strong frequencies in the area 0-40 Hz. A group of 52 teachers/musicstudents and non musicstudents was trying to assess what they thought, experiences and tried to describe why they thought as they did, when they listen on three different versions of same musical piece. Without low frequent bass, original and strengthened bass, randomly mixed. Several different musical pieces was used in same survey. The work also makes a commitment to theories about the people's hearing and the will of ‘selfmotion’. The result gives a hint that participators in the survey prefer to listen to music on “balance”, rather then music with reinforced low bassfrequencies.

Αντικείμενο αυτής της διπλωματικής εργασίας είναι η εφαρμογή των θεμελιωδών αρχών της ψυχοακουστικής θεωρίας στο συνδυασμό ηχητικών πηγών. Ειδικότερα, εισάγεται μια νέα προσέγγιση (ψηφιακής) μίξης σημάτων (καναλιών) ήχου, η οποία βασίζεται στη αντιληπτότητα των ήχων από το ανθρώπινο από το ανθρώπινο ακουστικό σύστημα. Στόχος της εργασίας είναι να αναδείξει τα πλεονεκτήματα της νέας προσέγγισης σε σχέση με τη συμβατική μέθοδο μίξης. Για το σκοπό αυτό πραγματοποιείται ένας μεγάλος αριθμός ένθεν και ένθεν μίξεων σε ένα σύνολο από διαθέσιμα αρχεία ήχου και παρουσιάζονται σχετικά αποτελέσματα. / This diploma work applies some of the fundamental psychoacoustic principles to the combination of sound sources. A novel technique of perceptually–motivated signal dependent digital audio mixing is presented. The proposed Hierarchical Perceptual Mixing (HPM) method is implemented in the spectro–temporal domain. Its basic principle is to combine only the perceptually relevant components of the audio signals, derived after the calculation of the minimum masking threshold which is introduced in the mixing stage. Objective measures of various mixing scenarios are presented aiming to underline the advantages of HPM method over CM method (Convention Mixing).

Darbe tiriami iškraipymai audio sistemose ir kaip žmogaus klausa juos suvokia. Autorius sistemina tyrimus, bibliografinius įrašus. Pateikiama alternatyvi tyrimo metodika. Tyrimo rezultatai reikšmingi tobulinant garsinio signalo traktą. / This research is about distortion in audio systems and how human hearing perceives it. Author collects together data from other researches and compares them. The main goal of this research is to find, what type of audio distortion is most audible. Results of the work can be used to improve audio equipment design with properties of human hearing in mind.

The structured arrangement of sounds in musical pieces, results in the unique creation of complex acoustic mixtures. The analysis of these mixtures, with the objective of estimating the individual sounds which constitute them, is known as musical instrument sound source separation, and has applications in audio coding, audio restoration, music production, music information retrieval and music education. This thesis principally addresses the issues related to the separation of harmonic musical instrument sound sources in single-channel mixtures. The contributions presented in this work include novel separation methods which exploit the characteristic structure and inherent correlations of pitched sound sources; as well as an exploration of the musical timbre space, for the development of an objective distortion metric to evaluate the perceptual quality of separated sources. The separation methods presented in this work address the concordant nature of musical mixtures using a model-based paradigm. Model parameters are estimated for each source, beginning with a novel, computationally efficient algorithm for the refinement of frequency estimates of the detected harmonics. Harmonic tracks are formed, and overlapping components are resolved by exploiting spectro-temporal intra-instrument dependencies, integrating the spectral and temporal approaches which are currently employed in a mutually exclusive manner in existing systems. Subsequent to the harmonic magnitude extraction using this method, a unique, closed-loop approach to source synthesis is presented, separating sources by iteratively minimizing the aggregate error of the sources, constraining the minimization to a set of estimated parameters. The proposed methods are evaluated independently, and then are placed within the context of a source separation system, which is evaluated using objective and subjective measures. The evaluation of music source separation systems is presently limited by the simplicity of objective measures, and the extensive effort required to conduct subjective evaluations. To contribute to the development of perceptually relevant evaluations, three psychoacoustic experiments are also presented, exploring the perceptual sensitivity of timbre for the development of an objective distortion metric for timbre. The experiments investigate spectral envelope sensitivity, spectral envelope morphing and noise sensitivity.

The structured arrangement of sounds in musical pieces, results in the unique creation of complex acoustic mixtures. The analysis of these mixtures, with the objective of estimating the individual sounds which constitute them, is known as musical instrument sound source separation, and has applications in audio coding, audio restoration, music production, music information retrieval and music education. This thesis principally addresses the issues related to the separation of harmonic musical instrument sound sources in single-channel mixtures. The contributions presented in this work include novel separation methods which exploit the characteristic structure and inherent correlations of pitched sound sources; as well as an exploration of the musical timbre space, for the development of an objective distortion metric to evaluate the perceptual quality of separated sources. The separation methods presented in this work address the concordant nature of musical mixtures using a model-based paradigm. Model parameters are estimated for each source, beginning with a novel, computationally efficient algorithm for the refinement of frequency estimates of the detected harmonics. Harmonic tracks are formed, and overlapping components are resolved by exploiting spectro-temporal intra-instrument dependencies, integrating the spectral and temporal approaches which are currently employed in a mutually exclusive manner in existing systems. Subsequent to the harmonic magnitude extraction using this method, a unique, closed-loop approach to source synthesis is presented, separating sources by iteratively minimizing the aggregate error of the sources, constraining the minimization to a set of estimated parameters. The proposed methods are evaluated independently, and then are placed within the context of a source separation system, which is evaluated using objective and subjective measures. The evaluation of music source separation systems is presently limited by the simplicity of objective measures, and the extensive effort required to conduct subjective evaluations. To contribute to the development of perceptually relevant evaluations, three psychoacoustic experiments are also presented, exploring the perceptual sensitivity of timbre for the development of an objective distortion metric for timbre. The experiments investigate spectral envelope sensitivity, spectral envelope morphing and noise sensitivity.

Based on prior research on concepts such as kinesonic feedback, and the here presented concept of kinesonic perspective, this study investigates whether or not players prefer binaurally recorded Foley over monophonically recorded Foley in a first-person video game environment, and whether or not binaural Foley has an impact on their relationship to, or perception of, the avatar. A game environment was created, in which players could switch at will between two audio modes; one containing binaurally recorded Foley, and the other containing monophonically recorded Foley. In the study, subjects were asked to state their preference between the two modes, motivate said preference, rate the two modes on three attributes, and answer questions regarding their perceived relationship to the avatar. Results showed no statistical significance regarding the preference of the sample, but a potential link was found between subjects’ preference and their perceived believability of the Foley sounds. The qualitative results showed that the binaural Foley had a complex impact on the subjects’ perception of and relationship to the avatar. The qualitative data also showed that subjects generally felt that the binaural Foley originated from their own body. Due to the small sample size and diversity of subject opinions it is however difficult to make any generalizations regarding the average player. Further research could investigate what role sound plays in the player’s ability to embody the avatar, as well as more thoroughly investigate the complex relationship between the kinesonic perspective of the avatar and that of the player.