Thursday, September 29, 4:00 pm — 6:00 pm (Rm 409B)
Durand R. Begault, NASA Ames Research Center - Moffet Field, CA, USA; Charles M Salter Associates- Audio Forensic Center - San Francisco, CA USA
P7-1 Minimum-Audible Angles in Wave-Field Synthesis: A Case Study—Florian Völk, Technische Universität München - München, Germany; WindAcoustics UG (haftungsbeschränkt) - Windach, Germany
Wave-field synthesis aims at creating a predefined sound field within a restricted listening area. Implementing and maintaining a wave-field-synthesis system is rather costly, as a high number of loudspeakers must be set up meticulously and driven individually. Despite this effort, a physically perfect synthesis is not possible. This contribution addresses a critical and relevant benchmark of synthesis quality: perceptual directional resolution. The study was conducted with a typical living-room-scale system by measuring minimum-audible angles in the horizontal plane with different stimuli. The results indicate that the procedure provides a directional resolution close to that of real sound sources.
Convention Paper 9619 (Purchase now)
P7-2 Accurate Timbre and Frontal Localization without Head Tracking through Individual Eardrum Equalization of Headphones—David Griesinger, David Griesinger Acoustics - Cambridge, MA, USA
The ear and brain perceive the vertical position of sounds by matching the timbre detected at the eardrum of a listener to timbre patterns built up by that individual over a long period of time. But the eardrum timbre depends dramatically on ear canal resonances between 1000 Hz and 6000 Hz that boost the pressure at the eardrum as much as 20 dB. These resonances are highly individual and are either eliminated or altered by headphones. In-head localization is the result. We have developed an app that uses an equal-loudness procedure to measure and restore the natural timbre. Accurate timbre and frontal localization are then perceived without head-tracking, and binaural recordings can be stunningly realistic.
Convention Paper 9620 (Purchase now)
P7-3 The Room-in-Room Effect and its Influence on Perceived Room Size in Spatial Audio Reproduction—Richard J. Hughes, University of Salford - Salford, Greater Manchester, UK; Trevor Cox, University of Salford - Salford, UK; Ben Shirley, University of Salford - Salford, Greater Manchester, UK; Paul Power, University of Salford - Salford, Greater Manchester, UK
In spatial audio it can be desirable to give the impression of a target space (e.g., a church). Often the reproduction environment is assumed acoustically dead; in practice most listening spaces (e.g., domestic living rooms) introduce significant reflections. The result is a room-in-room effect: a complex interaction of target and reproduction environments. This study investigates the influence on perceived room size. A number of target spaces were measured and rendered for loudspeaker playback. Reproduction rooms were measured, with variations produced via impulse response adjustment. Dynamic binaural playback allowed different target and reproduction room combinations, with participants judging the size of environment being reproduced. Results indicate the more reverberant of the target and reproduction rooms is most commonly heard.
Convention Paper 9621 (Purchase now)
P7-4 Compressing Higher Order Ambisonics of a Personal Stereo Soundfield—Panji Setiawan, Member IEEE; Wenyu Jin, Member IEEE - Wellington, NZ
In this work we propose an approach to encode the multizone soundfield within the desired region that features a so-called bright zone with stereo sound effects based on higher order ambisonics (HOA) formats. We decompose the B-format signals for the complex multizone soundfield into the coefficients of a formulated planewave expansion. The multizone soundfield B-format signals are then directly compressed using state-of-the-art audio codecs. The results confirm the effectiveness of this HOA based multizone soundfield encoding. A significant reduction on the compression rate of the desired multizone soundfield with sufficient accuracy can be achieved by quantitatively analyzing the reproduction performance.
Convention Paper 9622 (Purchase now)