Music recordings contain the mixed contribution of multiple overlapping instruments. In order to better understand the music, it would be beneficial to understand each instrument independently. This thesis focuses on separating the individual instrument recordings within a song. In particular, we propose novel algorithms for separating instrument recordings given only their mixture. When the number of source signals does not exceed the number of mixture signals, we focus on a subclass of source separation algorithms based on joint diagonalization. Each approach leverages a different form of source structure. We introduce repetitive structure as an alternative that leverages unique repetition patterns in music and compare its performance against the other techniques. When the number of source signals exceeds the number of mixtures (i.e. the underdetermined problem), we focus on spectrogram factorization techniques for source separation. We extend single-channel techniques to utilize the additional spatial information in multichannel recordings, and use phase information to improve the estimation of the underlying components.

Thesis (MScEng)--University of Stellenbosch, 2003. / ENGLISH ABSTRACT: Two non-destructive methods of extracting audio from Edison phonographic cylinders were investigated. A recording device with high accuracy positioning was designed and manufactured. A microscopic image method was investigated first. Surface images of the cylinder were obtained using a webcamera. An audio signal was then extracted from the width modulation. Results were not pleasing as echoes caused by intergroove modulation were perceptable. The audio also lacked resolution. The true modulation of the audio is not embedded in the width, but in the depth of the groove. The second audio extraction method involved using a laser pick-up from a compact disc player to measure the depth of the groove. Three laser recording methods were investigated. The first was forward recording, that measured the depth modulation in the recording direction of the groove. The second method, backward recording, was identical to forward recording with the mechanical system moving in reverse. Four recordings from different positions in the groove were combined to create an audio signal. This combination of recordings showed a substantial improvement in the signal-to-noise ratio. A third recording method, transverse recording, that measured the whole depth profile of the groove was also investigated. The groove profile was then processed to an audio signal. A manual audio restoration program was written to replace visible sections of distorted data with better interpolations. Two speech enhancement methods were investigated, the first being the most commonly used speech enhancement method for digital audio restoration, Short-Time Spectral Attenuation (STSA). The second method is based on linear predictive coefficient (LPC) estimation of short-time frames. The two methods were evaluated by means of listening tests. The LPC enhancement method was preferred because it enhanced the intelligibility of the speech. / AFRIKAANSE OPSOMMING: Twee nie-destruktiewe metodes om klank van Edison-fonograafsilinders te onttrek, is ondersoek. 'n Opneemtoestel, wat die silinders met baie hoë akkuraatheid posisioneer, IS ontwerp en vervaardig. 'n Mikroskopiese beeldrnetode IS as eerste klankonttrekkingsmetode ondersoek. Mikroskopiese beelde is met 'n webkamera van die silinderoppervlak geneem. Klank is vanuit die wydtemodulasie sigbaar in die beelde onttrek. Resultate was nie bevredigend nie weens groefintermodulasie-eggo's en 'n tekort aan resolusie. Die ware modulasie van die klank is nie in die wydte van die groefie gegraveer nie, maar in die diepte. Die tweede klankonttrekkingsmetode gebruik 'n aangepaste lasersensor van 'n CD-speler om die dieptemodulasie van die groefie te meet. Drie laseropneemmetodes is ondersoek. Die eerste is voorwaartse opname, wat die dieptemodulasie in die opneemrigting van die groefie meet. 'n Tweede opneemmetode, truwaartse opname, is identies aan voorwaartse opname, behalwe dat die meganiese stelsel in trurat beweeg. Vier opnames vanuit verskillende posisies in die groefbreedte is gekombineer om 'n klanksein te vorm. Die kombinasie van vier opnames toon 'n beduidende verbetering op die sein-tot-ruis-verhouding. Dit het aanleiding gegee tot die derde opneemmetode, dwarsskandering, wat die hele profiel van die groef meet. Die groefprofiel word dan verwerk tot 'n klanksein. 'n Handoudiorestourasieprogram is geskryf om sigbare verwringing in die klanksein met beter interpolasies te vervang. Twee spraakverheffingsmetodes is ondersoek. Short- Time Spectral Attenuation (STSA) is die mees gebruikte metode vir oudiorestourasie. 'n Tweede spraakverheffingsmetode wat van 'n lineêre voorspellingskoëffisiëntafskatting (LPC-afskatting) van korttydraampies gebruik maak, is ook toegepas. Die twee metodes is deur luistertoetse teen mekaar opgeweeg. Die LPCmetode is verkies aangesien dit die verstaanbaarheid van die spraak beter behoue laat bly.

Orientador: Pedro Peixoto Ferreira / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Filosofia e Ciências Humanas / Made available in DSpace on 2018-08-25T12:51:50Z (GMT). No. of bitstreams: 1 Malhao_RafaeldaSilva_M.pdf: 19665783 bytes, checksum: 97dedddf16af7fdc50c3ab0adc13a7b9 (MD5) Previous issue date: 2014 / Resumo: A presente dissertação tem como objeto e objetivo central compreender o processo tecno-genético de formação dos DJs de Música Eletrônica de Pista (MEP) para uma atuação efetiva frente a uma pista de dança. Para dar conta da tarefa que me propus dediquei-me a analisar este processo a partir de três de abordagens distintas, a saber, tecnologia, técnica e habilidade, que assumem dinâmicas relacionais diferentes que dependem do objetivo e combinação estabelecida entre elas, e a partir destes diferentes cenários relacionais estas combinações orientam ritmos específicos de interação entre humanos e máquinas. Estas combinações e ritmos foram o núcleo para a análise mais profícuo identificado para explorar o DJ como conceito e prática no âmbito da MEP. Estas três abordagens visam desdobrar as questões relativas a cada tópico supracitado e a integração destas abordagens se dá por meio de uma experiência estética não contemplativa. A primeira abordagem tem como preocupação central as diferentes formas em que a tecnologia de reprodução sonora foi relevante para MEP e visa constituir uma base material da mudança tecnológica para as discussões abordadas subsequentemente. A segunda abordagem parte desta base tecnológica a fim de apresentar as possíveis formas de constituição das habilidades, das técnicas e do corpo por meio da atuação sinérgica para fins comuns entre DJs e tecnologias de reprodução sonora. A terceira abordagem se vale das duas anteriores para tentar compreender a relação que se estabelece entre estes modos tecnológicos e técnicos de formação das habilidades e percepção que contribuem na forma de interação entre DJs e pista de dança, atendo-se principalmente, nas potencialidades e especificidades de uma proposta tecno-estética que busca escapar da passividade contemplativa na relação entre público e executores de atos estéticos. Este percurso se fez necessário para a compreensão do papel das tecnologias na formação dos sentidos e das ações a eles correspondentes durante o processo de aprendizado das técnicas sendo elas de discotecagem ou modos de dança. Por fim, identifico, assim como alguns autores que perpassam o texto, que o modo de percepção, bem como o corpo que percebe ? e todas as implicações desta situação ? não são dados a priori, e sim, se constituem ao longo das diferentes interações com o ambiente e com a tecnologia. E que uma abordagem estética que privilegie a experiência estética mediada por objetos que não são necessariamente estéticos, mas objetos que possibilitam diferentes reticulações do espaço e do tempo por meio do seu modo de manipulação e inserção em contextos específicos foi a maneira mais interessante para descrever a relação entre DJs, tecnologias e pista de dança / Abstract: The aim of this study is to understand the techno-genetic process of the development of Electronic Dance Music (EDM) DJs in an effective performance in the dance floor. To be able to accomplish this task I analyse the process from three distinct approaches, namely technology, techniques, and skills that assume different relational dynamics depending on the goal and the combination stabilished among them, and from those different relational scenaries those combinations orient toward specific rhythms of interaction between mankind and machines.These combinations and rhythms were the most proficuous nucleous to the analysis, identified to explore the DJ as concept and practise in EDM. Those three approaches are to unfold the issues regarding each topic above mentioned and the integration of the approaches happens through a non-contemplative aesthetic experience. The first approach aims the different ways sound reproduction technology was relevant to EDM and intends to build a material base of technological change to the discussions subsequently dealt. The second approach derives from said technological base in order to present the possible ways of developing skills, techniques, and body by the synergic movement to common goals between DJs and sound reproduction technology. The third approach derives from the first two aiming to understand the relation stablished among the technological ways and the techniques to form the skills and perceptions that contribute the way of interaction between DJs and the dance floor. It focuses mainly in potencialities and specificity of the techno-aesthetic proposal that tries to scape from contemplative passivity in the relation between the audience and the performer of aesthetic acts. All this process was needed to understand the role the technologies play in the formation of senses and actions corresponding to them during the technique learning process of either DJing or dance moves. Consequently, I identified, as well as some autors who perpassed the text, the fact that the way of perception and the body that perceives and also all implications of this situation are not given a priori, and that way, are constituted during the different interactions with the environment and technology. Also an aesthetic approach that previleges the aesthetic experience mediated by objects not necessarily aesthetic, but objects with different reticulations of the space and the time through their form of manipulation and inserction in specific contexts was the most interesting way to describe the relation between DJs, technologies, and dance floor / Mestrado / Sociologia / Mestre em Sociologia

In reviewing the events of the advances of science and technology of the past two decades one is struck by the magnificence of man's accomplishments. The first moon walk televised live in 1969, the widespread utilization of color television receivers, the educational uses of sophisticated audio-visual equipment such as overhead projectors, slide projection, sound tape recorders, close-circuit television and videotape and the almost omniscient usage of television, is ample evidence to demonstrate that the tools necessary to accomplish a task are readily accessible items in this age. We are introduced to new gadgets, innovations, and events (like the moon walk) at such a rapid pace that we have become more flexible and more receptive to change; so much so that at times many of us are even blase about nearly miraculous accomplishments.

Thesis (M. Phil. (Music Technology)) -- University of Stellenbosch, 2006. / ENGLISH ABSTRACT: Modern digital signal processing, allowing a much greater degree of flexibility in audio processing and therefore greater potential for noise removal, pitch correction, filtering and editing, has allowed transfer and audio restoration engineers a diversity of ways in which to “improve” or “reinterpret” (in some cases even drastically altering) the original sound of recordings. This has lead to contrasting views regarding the role of the remastering engineer, the nature and purpose of audio restoration and the ethical implications of the restoration process. The influence of audio restoration on the recorded legacy of a performing artist is clearly illustrated in the case of Maria Callas (1923 - 1977), widely regarded not only as one of the most influential and prolific of opera singers, but also one of the greatest classical musicians of all time. EMI, for whom Callas recorded almost exclusively from 1953 - 1969, has reissued her recordings repeatedly, continually adapting their sound “to the perceived preferences of the record-buying public” (Seletsky 2000: 240). Their attempts at improving the sound of Callas’s recordings to meet with the sonic quality expected of modern recordings, as reissued in the latest releases that form part of EMI’s Callas Edition, Great Recordings of the Century (GROTC) and Historical Series, have resulted in often staggeringly different reinterpretations of the same audio material that bear no resemblance to previous CD or LP incarnations or “evince no consolidated conviction about exactly how Callas’s voice should sound.” In essence, some commentators argue that the “Callas sound” we hear on recent CD releases is not necessarily exactly as the great diva might have sounded. The purpose of this study is to consider the influence of audio restoration and remastering techniques on the recorded legacy of Callas, by illustrating the sometimes startlingly different ways in which her voice has been made to sound, examining and comparing the way in which different remasterings of the same audio material can vary in quality, as well as demonstrating how vastly different sonic reinterpretations of a single recording can affect our perception of an artist’s “true” sound. To this end, various reissues of six different complete opera recordings, including four studio recordings: Tosca (1953), Lucia di Lammermoor (1953), Norma (1954), Madama Butterfly (1955), as well as two “live” performances of Macbeth (1953) and La Traviata (1958), have been evaluated and compared, using the “true” sound of Callas’s voice as reference in comparing the different remasterings. Pitch and frequency spectrum analysis was used to confirm or support any subjective claims and observations and further analysis performed with the aid of a specialised Matlab algorithm. / AFRIKAANSE OPSOMMING: Moderne digitale seinprossesering bied kragtige en veelsydige moontlikhede vir die verwerking van klankseine. Die groter potensiaal vir ruisverwydering, toonhoogte verstelling, filtrering en redigering van opnames bied klankingenieurs ‘n wye verskeidenheid van maniere om die oorspronklike klank van opnames te verbeter, te interpreteer en soms ingrypend te verander. Dit het aanleiding gegee tot teenstrydige en uiteenlopende menings oor die funksie van die klankrestourasie-ingenieur, die aard en doel van klankrestourasie en die etiese gevolge van die restourasieproses. Die invloed van klankrestourasie op die klanknalatenskap van ‘n uitvoerende kunstenaar kan duidelik bestudeer word in die geval van Maria Callas (1923 – 1977), algemeen aanvaar as een van die mees invloedryke en grootse klassieke musici van alle tye. Die platemaatskappy EMI, vir wie Callas feitlik uitsluitlik vanaf 1953 tot 1969 opgeneem het, het haar klankopnames reeds verskeie kere heruitgereik en die klank daarvan deurlopend aangepas om aanklank te vind by die “veronderstelde voorkeure van die publiek” (Seletsky 2000: 240). EMI se pogings om die klank van Callas se opnames te verbeter om aan die klankvereistes van moderne opnames te voldoen, het ontaard in dikwels aangrypend verskillende interpretasies van dieselfde audio materiaal wat geen ooreenkomste toon met vorige laserskyf of langspeelplaat uitgawes nie, asook “geen vasgestelde oortuigings openbaar oor hoe Callas se stem presies moet klink nie.” Sommige critici argumenteer dat die “Callas klank” wat ons op hedendaagse CD uitgawes hoor, nie noodwendig klink soos wat Callas werklik geklink het nie. Die doel van hierdie studie is om die invloed van klankrestourasie op die klanknalatenskap van Callas te bestudeer deur die verskillende wyses waarop die klank van haar stem aangepas is te illustreer, die verskille in klankkwaliteit tussen verskillende uitgawes van dieselfde materiaal te ondersoek en te vergelyk, asook te demonstreer hoe uiteenlopend verskillende interpretasies van ‘n enkele opname die persepsie van ‘n kunstenaar se “ware” klank kan affekteer. Vir hierdie doel is verkeie uitgawes van ses verskillende volledige opera opnames, insluitend vier studio opnames van onderskeidelik Tosca (1953), Lucia di Lammermoor (1953), Norma (1954) en Madama Butterfly (1955), asook twee “lewendige” opnames van Macbeth (1952) en La Traviata (1958) bestudeer deur Callas se “ware” klank as maatstaf te gebruik om die onderskeie opnames te vergelyk. Toonhoogte- en frekwensie spektrum analise, asook analise deur middel van ‘n gespesialiseerde Matlab algoritme, is deurlopend gebruik om enige subjektiewe gevolgtrekkings en waarnemings te staaf.

Submitted by Filipe dos Santos (fsantos@pucsp.br) on 2018-07-04T12:24:09Z No. of bitstreams: 1 Fernanda Manzo Ceretta.pdf: 64197918 bytes, checksum: 89e46d8729046a5162627527f8dcd7bc (MD5) / Made available in DSpace on 2018-07-04T12:24:09Z (GMT). No. of bitstreams: 1 Fernanda Manzo Ceretta.pdf: 64197918 bytes, checksum: 89e46d8729046a5162627527f8dcd7bc (MD5) Previous issue date: 2018-06-26 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / This research analyzes the sound design of movie monsters, especially their voices. Chewbacca (Star Wars, 1977), Godzilla (1954) and Predator (1987) constitute our corpus. These monsters have voices composed by designers who have experimented different creation processes, using sounds generated by nature, body and manipulated objects, in order to create the sound identity of these characters. We investigate the contexts of these creation processes and the resulting sounds in their particularities to make a proposition of a method for creating the sound of monsters. Our method covers the potential sources of base sounds and other sonic characteristics such as frequencies, timbre and intensity. The research was based in the observation of the selected audio-visual materials and in the documentation available regarding the making ofs (which is vast, given the popularity of the selected monsters). The thesis is based mainly on articulations with the works of Rick Altman, Michel Chion and William Whittington, on the cinematographic sound, and of Theo Van Leeuwen in his proposition of sonorous analysis / Este trabalho analisa o sound design de monstros do cinema, sobretudo suas vozes. Chewbacca (Star Wars, 1977), Godzilla (1954) e Predador (1987) constituem o corpus da presente pesquisa. Estes monstros possuem vozes compostas por designers que experimentaram diferentes processos de criação, utilizando sons na natureza, do corpo e de objetos manipulados para criar a identidade sonora destas personagens. investigamos os contextos destes processos de criação e os sons criados, em suas particularidades, para compor uma proposta de método de composição de som de monstros, o qual abarca as potenciais fontes dos sons de base e demais características sonoras, como frequências, timbres e intensidade. A pesquisa foi feita a partir da observação dos materiais audiovisuais selecionados e do resgate da documentação disponível sobre os bastidores da criação dos mesmos (bastante vasta dada a popularidade dos monstros selecionados). A tese se baseia sobretudo em articulações com obras de Rick Altman, Michel Chion, William Whittington acerca do som cinematográfico e em Theo Van Leeuwen em sua proposição de análise sonora

Virtual three-dimensional (3D) auditory displays utilize signal-processing techniques to alter sounds presented through headphones so that they seem to originate from specific spatial locations around the listener. In some circumstances bone-conduction headsets (bonephones) can provide an alternative sound presentation mechanism. However, existing 3D audio rendering algorithms need to be adjusted to use bonephones rather than headphones. This study provided anchor points for a function of shift values that could be used to adapt virtual 3D auditory displays for use with bonephones. The shift values were established by having participants adjust phase and amplitude of two waves in order to cancel out the signal and thus produce silence. These adjustments occurred in a listening environment consisting of air-conducted and bone-conducted tones, as well as air- conducted masking. Performance in the calibration condition suggested that participants understood the task, and could do this task with reasonable accuracy. In the bone-to-air listening conditions, the data produced a clear set of anchor points for an amplitude shift function. The data did not reveal, however, anchor points for a phase shift function the data for phase were highly variable and inconsistent. Application of shifts, as well as future research to establish full functions and better understand phase are discussed, in addition to validation and follow-up studies.

Thesis (MPhil) -- University of Stellenbosch, 2000. / ENGLISH ABSTRACT: The most neglected element in television reporting is the sound track. The problem is illustrated by the fact that there are currently no specialised textbooks, or training courses, on sound recording for television reporting, anywhere in the world. Textbooks that deal with television reporting dedicate very little space to sound recordings. With the growing competition in television news, news teams are increasingly becoming smaller. It is common practice these days to have a news team consisting of only a cameraperson and a reporter. The cameraperson is also responsible for the sound. Two television stations, namely NYl in New York and Channel One Television in England, have already dispensed with the cameraperson and send out only a reporter. This dissertation addresses the above-mentioned problem by doing research on the sound equipment, recording techniques and production techniques that are useful for effective sound recordings during single camera television reporting. Chapter two explains the functions of the different departments in a television station, as well as the duties of the staff. Chapter three explains basic television principles, terminology and equipment that the sound person uses daily and needs to understand to perform his work optimally. Chapterfour gives the basic terms that are needed to follow a conversation on sound recording. Terms like decibel, stereo and digital sound are explained. The chapter also covers basic electricity and sound equipment. Chapter five covers microphones under three headings, namely: electrical characteristics, acoustic characteristics and microphone design. The chapter also covers associated equipment, explains the sound facilities on video cameras and gives a list of possible sound equipment that can be used during a production. Chapter six covers sound recordings, principles and techniques under the following headings: • Perspective and boom swinging, which deals with sound perspective and boom swinging. • Rigging of cables, which gives practical tips for laying cables inside and outside buildings. • Recording principles, which gives practical tips on sound recordings. • Interviews, which includes recording tips for television interviews and reporting. • Reporting, which covers reporting, media conferences and public events. • Commentary recordings, which deals with the preparation and recording of voice over. • Music recordings, which deals with instruments and bands, and suggests microphone positions. • Telephone lines, which covers the use of telephone lines for reporting. • Location reconnaissance, which gives practical tips on pre-production planning. • Guidelines for sound persons during productions, which concludes the chapter and the dissertation with practical tips on behaviour during local, foreign and/or dangerous productions. / AFRIKAANSE OPSOMMING: Die veranderlike wat die meeste afgeskeep word in televisieverslaggewing, is die klankbaan. Die probleem word onderstreep deur die feit dat daar wêreldwyd tans geen gespesialiseerde handboeke of opleidingskursusse bestaan wat oor klankopnames vir televisieverslaggewing handel nie. Handboeke wat handeloor televisieverslaggewing wy ook baie min ruimte aan klankopnames. Met die groeiende kompetisie in televisienuus raak nuusspanne toenemend kleiner. Dit is reeds algemene praktyk dat die nuusspan slegs uit 'n kamerapersoon en 'n verslaggewer bestaan. Die kamerapersoon moet dus ook die klankopnames doen. Twee televisiestasies, naamlik NYl in New York en Channel One Television in Engeland, het reeds die kamerapersoon uitgeskakel en stuur slegs 'n verslaggewer uit. Hierdie verhandeling spreek bogenoemde probleem aan deur navorsing te doen oor die klanktoerusting, opnametegnieke en produksietegnieke wat nuttig is vir effektiewe klankopnames tydens enkelkameratelevisieverslaggewing. Hoofstuk twee verduidelik die funksies van die verskillende departemente in 'n televisiestasie sowel as die pligte van die personeel. Hoofstuk drie verduidelik basiese televisiebeginsels, -terminologie en -toerusting wat die klankpersoon daagliks mee werk en dus moet verstaan om sy werk optimaal te verrig. Hoofstuk vier gee die basiese terme wat nodig is om 'n gesprek oor klankopnames te volg. Begrippe soos desibel, stereo en digitale klank word verduidelik. Die hoofstuk behandelook basiese elektriese beginsels en klanktoerusting. Hoofstuk vyf bespreek mikrofone onder drie indelings naamlik: elektriese eienskappe, akoestiese eienskappe en mikrofoonontwerp. Die hoofstuk dek ook aanverwante toerusting, verduidelik die klankfasiliteite op videokameras en gee 'n lys van klanktoerusting wat tydens produksies gebruik kan word. Hoofstuk ses is die belangrikste en bespreek klankopnames, beginsels en tegnieke onder die volgende opskrifte: • Perspektief en boomhantering, waaronder klankperspektief en boomhantering behandel word. • Lê van kabels, wat praktiese wenke gee vir die lê van kabels binne en buite geboue. • Opnamebeginsels, wat praktiese wenke gee in verband met klankopnames. • Onderhoude, wat opnamewenke gee in verband met televisieonderhoude en verslaggewing. • Verslaggewing, wat verslaggewing, nuuskonferensies en openbare geleenthede dek. • Kommentaaropnames, wat handeloor die voorbereiding vir, en opneem van kommentaar. • Musiekopnames, wat musiekinstrumente en orkeste bespreek en mikrofoonposisies voorstel. • Telefoonlyne, waaronder die gebruik van telefoonlyne vir verslaggewing bespreek word. • Terreinverkenning, wat praktiese riglyne gee vir voorproduksie-ondersoeke. • Riglyne vir klankpersone tydens produksies, wat die hoofstuk en die studie afsluit met praktiese wenke vir gedrag tydens plaaslike, buitelandse en/of gevaarlike produksies.

The control of modern audio studios is complex. Audio mixing desks have grown to the point where they contain thousands of parameters. The control surfaces of these devices do not reflect the routing and signal processing capabilities that the devices are capable of. Software audio mixing desk editors have been developed that allow for the remote control of these devices, but their graphical user interfaces retain the complexities of the audio mixing desk that they represent. In this thesis, we propose a grid approach to audio mixing. The developed grid audio mixing desk editor represents an audio mixing desk as a series of graphical routing matrices. These routing matrices expose the various signal processing points and signal flows that exist within an audio mixing desk. The routing matrices allow for audio signals to be routed within the device, and allow for the device’s parameters to be adjusted by selecting the appropriate signal processing points. With the use of the programming interfaces that are defined as part of the Studio Connections – Total Recall SDK, the audio mixing desk editor was integrated with compatible DAW applications to provide persistence of audio mixing desk parameter states. Many audio studios currently use digital networks to connect audio devices together. Audio and control signals are patched between devices through the use of software patchbays that run on computers. We propose a double grid-based FireWire patchbay aimed to simplify the patching of signals between audio devices on a FireWire network. The FireWire patchbay was implemented in such a way such that it can host software device editors that are Studio Connections compatible. This has allowed software device editors to be associated with the devices that are represented on the FireWire patchbay, thus allowing for studio wide control from a single application. The double grid-based patchbay was implemented such that it can be hosted by compatible DAW applications. Through this, the double grid-based patchbay application is able to provide the DAW application with the state of the parameters of the devices in a studio, as well as the connections between them. The DAW application may save this state data to its native song files. This state data may be passed back to the double grid-based patchbay when the song file is reloaded at a later stage. This state data may then be used by the patchbay to restore the parameters of the patchbay and its device editors to a previous state. This restored state may then be transferred to the hardware devices being represented by the patchbay.

Digital audio network technologies are becoming more prevalent in audio related environments. Yamaha Corporation has created a digital audio network solution, named mLAN (music Local Area Network), that uses IEEE 1394 as its underlying network technology. IEEE 1394 is a digital network technology that is specifically designed for real-time multimedia data transmission. The second generation of mLAN is based on the Plural Node Architecture, where the control of audio and MIDI routings between IEEE 1394 devices is split between two node types, namely an Enabler and a Transporter. The Transporter typically resides in an IEEE 1394 device and is solely responsible for transmission and reception of audio or MIDI data. The Enabler typically resides in a workstation and exposes an abstract representation of audio or MIDI plugs on each Transporter to routing control applications. The Enabler is responsible for configuring audio and MIDI routings between plugs on different Transporters. A Hardware Abstraction Layer (HAL) within the Enabler allows it to uniformly communicate with Transporters that are created by various vendors. A plug-in mechanism is used to provide this capability. When vendors create Transporters, they also create device-specific plug-ins for the Enabler. These plug-ins are created against a Transporter HAL Application Programming Interface (API) that defines methods to access the capabilities of Transporters. An Open Generic Transporter (OGT) guideline document which models all the capabilities of Transporters has been produced. These guidelines make it possible for manufacturers to create Transporters that make use of a common plug-in, although based on different hardware architectures. The introduction of the OGT concept has revealed additional Transporter capabilities that are not incorporated in the existing Transporter HAL API. This has led to the underutilisation of OGT capabilities. The main goals of this investigation have been to improve the Enabler’s plug-in mechanism, and to incorporate the additional capabilities that have been revealed by the OGT into the Transporter HAL API. We propose a new plug-in mechanism, and a new Transporter HAL API that fully utilises both the additional capabilities revealed by the OGT and the capabilities of existing Transporters.