Ž . Computer Networks and ISDN Systems 30 1998 1933–1940 Tools and widgets for spatial sound authoring Jens Herder ) UniÕersity of Aizu, Aizu-Wakamatsu, Fukushima-ken 965-8580, Japan Abstract Broader use of virtual reality environments and sophisticated animations spawn a need for spatial sound. Until now, spatial sound design has been based very much on experience and trial and error. Most effects are hand-crafted, because good design tools for spatial sound do not exist. This paper discusses spatial sound authoring and its applications, including shared virtual reality environments based on VRML. New utilities introduced by this research are an inspector for sound sources, an interactive resource manager, and a visual soundscape manipulator. The tools are part of a sound spatialization framework and allow a designerrauthor of multimedia content to monitor and debug sound events. Resource constraints such as limited sound spatialization channels can also be simulated. q 1998 Elsevier Science B.V. All rights reserved. Keywords: Spatial sound authoring; Virtual reality environments; Multimedia; Spatial media; User interface design 1. Introduction More and more applications use virtual reality environments including spatial sound as a user inter- face. The demand for animations with impressive and immersive sound increases, as audio-visual equipment which can produce such effects becomes increasingly available. Spatial sound has migrated from special platforms to everyone’s desktop. This is due to better general-purpose processors, which al- low spatial sound processing in software, and hard- ware support, in the form of audio cards. Wide distribution of content including spatial sound for virtual reality environments over the inter- net was made possible with the introduction of the ) Tel.: q81-242-37-2579; Fax: q81-242-37-2706; E-mail: herder@u-aizu.ac.jp, www:http:rrwww.u-aizu.ac.jpr ;herderr Ž wx. Virtual Reality Modeling Language VRML 2.0 1 . Even though the specification does not cover all aspects of spatial sound, dramatic effects can be produced. Available tools for producing VRML con- tent have some support for spatial sound authoring, but in general they are not sufficient. We have wx developed widgets 2 , user interface objects with encapsulated geometry and behavior, to control and show properties of soundscapes and sound objects. 1.1. Spatial sound wx Spatial sound 3 is modeled by many attributes. Directionalization can be modeled by binaural ITD Ž . Ž interaural time difference , IID interaural intensity . wx difference , and pinnae effects 4 . Distance cues are based on delay, reverberation and loudness. The space, consisting of objects interacting with sound Ž waves, defines the reverberation and first- and . higher- order reflections. 0169-7552r98r$ - see front matter q 1998 Elsevier Science B.V. All rights reserved. Ž . PII: S0169-7552 98 00175-5