Sunday, May 21, 15:00 — 18:00
P12-01 Quantitative Investigation Artificial Room Simulations Reproduced by Channel-Based and Object-Based Surround Sound Systems
Bernard Camilleri (Presenting Author), Jakob Bergner (Author), Christoph Sladeczek (Author)
The introduction of object-based audio reproduction comes along with new challenges for the sound engineer to record, design, and synthesize reverberant sound fields due to the increased number of speakers and the placement of such. The aim of this paper is to show that several parameter settings from a digital reverberation unit produce contrasting reflectograms in a 5.0 channel-based setup and an object-based setup that can have effects on the perceived reverberant sound field. Conversely, established acoustical metrics derived from the measured room impulse responses (RIRs) in both multichannel reproduction setups do not highlight the differences noticed in the reflectograms. The potential consequences regarding individual system properties and the metrics themselves are discussed in this work.
Convention Paper 9741
P12-02 Comparative Perceptual Evaluation between Different Methods for Implementing Reverberation in a Binaural Context
Lorenzo Picinali (Presenting Author), Yuli Levtov (Author), David Poirier-Quinot (Author), Alexander Wallin (Author)
Reverberation has always been considered of primary importance in order to improve the realism, externalization and immersiveness of binaurally spatialized sounds. Different techniques exist for implementing reverberation in a binaural context, each with a different level of computational complexity and spatial accuracy. A perceptual study has been performed in order to compare between the realism and localization accuracy achieved using five different binaural reverberation techniques. These included multichannel Ambisonic-based, stereo and mono reverberation methods. A custom web-based application has been developed implementing the testing procedures and allowing participants to take the test remotely. Initial results with 54 participants show that no major difference in terms of perceived level of realism and spatialization accuracy could be found between four of the five proposed reverberation methods, suggesting that a high level of complexity in the reverberation process does not always correspond to improved perceptual attributes.
Convention Paper 9742
P12-03 Data-Driven Granular Synthesis
Sadjad Siddiq (Presenting Author)
Granular synthesis is a flexible method to create a wide range of complex sounds, like the sound of rain or water, using very short waveforms, called grains. To synthesize realistic, natural sounds appropriate grains are needed. In an earlier paper we already presented a method to extract grains from recordings of complex sounds. In this paper we describe an extension of the earlier method in which the end of incomplete grains is estimated to improve sound quality. Additionally synthesis parameters that allow us to recreate sound output very close to the original recordings are found automatically. A few seconds of audio input will provide enough data to synthesize sounds of arbitrary length. The necessary grains only require little memory and since synthesis parameters can also be varied to change the nature of the sound, this method is especially beneficial for video games. While empirical listening suggests that the synthesized waveforms sound natural, a formal listening test was not conducted. Sound samples are provided.
Convention Paper 9743
P12-04 Parametric Synthesis of Crowd Noises in Virtual Acoustic Environments
Vincent Grimaldi (Presenting Author), Christoph Böhm (Author), Stefan Weinzierl (Author), Henrik von Coler (Author)
This paper presents the design and evaluation of a parametric sound texture synthesis for the generation of crowd noise in virtual acoustic environments. It allows the control of the crowd size, its level of excitement, and its spatial distribution in real-time. A corpus-based concatenative approach is used to generate single streams of indistinct speech that are superimposed to create an unintelligible "babbling" texture. Speech material was recorded in semi-supervised group discussions in the anechoic chamber. The database is used in a real-time implementation with a subsequent rendering using dynamic binaural synthesis. Listening tests were conducted to evaluate the effect of different parameter settings, as well as the perceived “naturalness” of the simulation.
Convention Paper 9744
P12-05 Real or Illusion? A Comparative Study of Captured Ambiance vs. Artificial Reverberation in Immersive Audio Applications
Richard King (Presenting Author), Will Howie (Author), Jack Kelly (Author), Brett Leonard (Author)
Spatial audio researchers and content producers agree that the best source material for immersive audio is provided by the capture of acoustic signals at various elevations in a room. Where music recording is concerned, this technique is generally preferred over signal processing, as it provides a more natural and realistic impression of immersion. The authors’ previous work evaluated the content of rear height channels, which demonstrated that a group of listeners could not discriminate between real room sound and artificial reverberation, and showed no significant preference for either version. The current research investigates whether or not there is a preference for real source ambience over artificially generated reverberation in all four of the height channels (i.e., front and rear elevation) of a 9.1 immersive playback system. Results show some subjects can consistently discriminate between ambiences, but no consistent preference for ambience was observed.
Convention Paper 9745
P12-06 Investigating the Impact of a Music Stand on Stage Using Spatial Impulse Responses
Sebastià Vicenç Amengual Gari (Presenting Author), Malte Kob (Author)
A measurement set-up replicating a trumpet solo concert situation is arranged on stage by means of a music stand, a directive loudspeaker, and a microphone array. Spatial Room Impulse Responses are measured and analyzed to evaluate the acoustic impact of the music stand at the musician position, depending on the stand location and orientation. Results show that when the stand is orientated towards the receiver the sound level at high frequencies increases up to 9 dB. In some cases, the level of the stand reflection at high frequencies is higher than the source itself, due to its radiation characteristics. The effects of a possibly perceivable timbre change on stage are discussed.
Convention Paper 9746