Spatial sound generation and perception by amplitude panning techniques

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Doctoral thesis (article-based)
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Date

2001-08-03

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Language

en

Pages

42, [100]

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Report / Helsinki University of Technology Laboratory of Acoustics and Audio Signal Processing, Raportti / Teknillinen korkeakoulu, akustiikan ja äänenkäsittelytekniikan laboratorio, 62

Abstract

Spatial audio aims to recreate or synthesize spatial attributes when reproducing audio over loudspeakers or headphones. Such spatial attributes include, for example, locations of perceived sound sources and an auditory sense of space. This thesis focuses on new methods of spatial audio for loudspeaker listening and on measuring the quality of spatial audio by subjective and objective tests. In this thesis the vector base amplitude panning (VBAP) method, which is an amplitude panning method to position virtual sources in arbitrary 2-D or 3-D loudspeaker setups, is introduced. In amplitude panning the same sound signal is applied to a number of loudspeakers with appropriate non-zero amplitudes. With 2-D setups VBAP is a reformulation of the existing pair-wise panning method. However, differing from earlier solutions it can be generalized for 3-D loudspeaker setups as a triplet-wise panning method. A sound signal is then applied to one, two, or three loudspeakers simultaneously. VBAP has certain advantages compared to earlier virtual source positioning methods in arbitrary layouts. Previous methods either used all loudspeakers to produce virtual sources, which results in some artefacts, or they used loudspeaker triplets with a non-generalizable 2-D user interface. The virtual sources generated with VBAP are investigated. The human directional hearing is simulated with a binaural auditory model adapted from the literature. The interaural time difference (ITD) cue and the interaural level difference (ILD) cue which are the main localization cues are simulated for amplitude-panned virtual sources and for real sources. Psychoacoustic listening tests are conducted to study the subjective quality of virtual sources. Statistically significant phenomena found in listening test data are explained by auditory model simulation results. To obtain a generic view of directional quality in arbitrary loudspeaker setups, directional cues are simulated for virtual sources with loudspeaker pairs and triplets in various setups. The directional qualities of virtual sources generated with VBAP can be stated as follows. Directional coordinates used for this purpose are the angle between a position vector and the median plane (θcc), and the angle between a projection of a position vector to the median plane and frontal direction (Φcc). The perceived θcc direction of a virtual source coincides well with the VBAP panning direction when a loudspeaker set is near the median plane. When the loudspeaker set is moved towards a side of a listener, the perceived θcc direction is biased towards the median plane. The perceived Φcc direction of an amplitude-panned virtual source is individual and cannot be predicted with any panning law.

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Keywords

3-D audio, multichannel audio, amplitude panning, binaural auditory model

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Parts

  • V. Pulkki. Virtual sound source positioning using vector base amplitude panning. Journal of the Audio Engineering Society, 45(6) pp. 456-466, June 1997. [article1.pdf] © 1997 AES. By permission.
  • V. Pulkki and T. Lokki. Creating auditory displays to multiple loudspeakers using VBAP: A case study with DIVA project. In International Conference on Auditory Display, Glasgow, Scotland, 1998.
  • V. Pulkki. Uniform spreading of amplitude panned virtual sources. Proceedings of the 1999 IEEE Workshop on Applications of Signal Processing to Audio and Acoustics. Mohonk Mountain House, New Paltz, New York. [article3.pdf] © 1999 IEEE. By permission.
  • V. Pulkki. Generic panning tools for MAX/MSP. Proceedings of International Computer Music Conference 2000. pp. 304-307. Berlin, Germany, August, 2000. [article4.pdf] © 2000 by author.
  • V. Pulkki, M. Karjalainen, and J. Huopaniemi. Analyzing virtual sound source attributes using a binaural auditory model. Journal of the Audio Engineering Society, 47(4) pp. 203-217 April 1999. [article5.pdf] © 1999 AES. By permission.
  • V. Pulkki and M. Karjalainen. Localization of amplitude-panned virtual sources I: Stereophonic panning. Accepted to Journal of the Audio Engineering Society. [article6.pdf] © 2001 AES. By permission.
  • V. Pulkki. Localization of amplitude-panned virtual sources II: Two- and Three-dimensional panning. Accepted to Journal of the Audio Engineering Society. [article7.pdf] © 2001 AES. By permission.

Citation

Permanent link to this item

https://urn.fi/urn:nbn:fi:tkk-002908