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Towards a Spatial Ear Trainer

Summary

Tobias Neher

Tobias completed his PhD at the IoSR in 2004. His research project was in association with Meridian Audio Ltd, also supported by the Audio Engineering Society Education Foundation. He is now working for Oticon A/S at the Eriksholm Research Centre in Denmark.

Objectives

The development of a spatial audio ear trainer has been proposed and investigated. A review of the relevant literature has shown that although numerous researchers have simulated spatial characteristics of sound, the devised simulation algorithms were not (properly) verified with respect to their intended subjective effects, thus making them unsuitable for training purposes. Additionally, whilst various timbral ear-training systems have been set up, there is none for spatial quality. To address these shortcomings four spatial attributes of reproduced sound have been considered: source distance, source width, ensemble width and ensemble depth. For each attribute a processing algorithm was developed that allowed highly controlled changes in the respective percept. Using these algorithms four sets of stimuli were carefully generated with the aim of achieving unidimensional variation in terms of the qualities of interest. In order to allow detailed and reliable validation of the simulations' auditory effects, a sensory evaluation strategy was devised that relies on Multidimensional Scaling techniques and the elicitation of supplementary qualitative data as a means of obtaining a complete sensory profile of a group of stimuli. With the help of this methodology as well as critical listening panels the psychological structures of the sound excerpts were measured. Results showed that the envisaged unidimensionality of the source distance, ensemble width and ensemble depth samples was accomplished. As to the source width simulation, results were not as clear-cut, which was attributed to listener unfamiliarity with this perceptual construct and greater stimulus uncertainty. Nevertheless, the analyses unfolded only one major dimension, which is why all four attribute simulations were deemed suitable for the proposed training purposes.

Details

Towards a Spatial Ear Trainer

Tobias Neher
Francis Rumsey
Tim Brookes

Publications

  • Neher, T., Brookes, T., and Mason, R. (2006), "Musically Representative Test Signals for Interaural Cross-Correlation Coefficient Measurement," Acta Acustica united with Acustica, vol. 92, no. 5, pp. 787-796
  • Neher, T., Brookes, T., and Rumsey, F. (2006), "A Hybrid Technique for Validating Unidimensionality of Perceived Variation in a Spatial Auditory Stimulus Set," J. Audio Eng. Soc., vol. 54, no. 4, pp. 259-275
  • Brookes, T., and Neher, T. (2005), "Perceptually Unidimensional Control of Spatial Audio: A Pilot Study," Digital Music Research Network Workshop, London, UK, Dec. 21, 6 pages
  • Neher, T. (2004), "Towards a Spatial Ear Trainer," PhD Thesis, Institute of Sound Recording, University of Surrey, Guildford, UK
  • Neher, T., Brookes, T., and Rumsey, F. (2004), "Unidimensional Simulation of the Spatial Attribute 'Ensemble Depth' for Training Purposes - Part 2: Creation and Validation of Reference Stimuli," 116th Audio Engineering Society Convention, Berlin, Germany, May 8-11, paper 5998, 22 pages
  • Neher, T., Brookes, T., and Rumsey, F. (2003), "Unidimensional Simulation of the Spatial Attribute 'Ensemble Depth' for Training Purposes - Part 1: Pilot Study into Early Reflection Pattern Characteristics," Proceedings of the AES 24th International Conference on Multichannel Audio, Banff, Canada, June 26-28, 15 pages
  • Neher, T., Rumsey, F., Brookes, T., and Craven, P. (2003), "Unidimensional Simulation of the Spatial Attribute 'Ensemble Width' for Training Purposes," 114th Audio Engineering Society Convention, Amsterdam, The Netherlands, March 22-25, paper 5769, 19 pages
  • Neher, T., Rumsey, F., and Brookes, T. (2002), "Training of Listeners for the Evaluation of Spatial Sound Reproduction," 112th Audio Engineering Society Convention, Munich, Germany, May 10-13, paper 5584, 20 pages

Thesis Download

"Towards a Spatial Ear Trainer" is available as a 3.6MB download - NeherThesis.pdf