AES Vienna 2007: Paper Session P10

P10 - Psychoacoustics, Perception, and Listening Tests - 2

Sunday, May 6, 12:30 — 17:00

Chair: Sean Olive

P10-1 Verbal Elicitation and Scale Construction for Evaluating Perceptual Differences between Four Multichannel Microphone Techniques—William L. Martens, Sungyoung Kim, McGill University - Montreal, Quebec, Canada
A verbal elicitation task using triadic comparisons was completed by eight listeners to explore the adjectives that describe the audible differences between solo piano performances captured using four different multichannel microphone techniques. Although the elicited terms differed somewhat between listeners, a set of five bipolar adjective pairs were found to represent the most salient differences between the auditory imagery associated with multichannel-loudspeaker reproduction of the piano performances. These adjectives were used as the anchors for five attribute rating scales on which the same eight listeners rated each of the 32 stimuli that had been presented for triadic comparison. Stepwise multiple regression showed that ratings on three of the five attributes successfully predicted those listeners’ preference ratings for the same stimuli.
Convention Paper 7043 (Purchase now)

P10-2 Broadcast Loudness: Mixing, Monitoring, and Control—Alessandro Travaglini, FOX International Channels (Italy) - Rome, Italy
In the satellite broadcast era, to manage transmission from a digital platform that broadcasts dozens of channels and to guarantee loudness consistency to viewers has became a primary, yet difficult task. In this paper I describe my work in balancing the broadcasted loudness of the Italian satellite TV platform SKY Italia. In fact, for a few years, its transmissions suffered very audible loudness inconsistency, due to several factors, such as numbers of channels, various content offerings, different mastering levels in between programs, and interstitials, outsourcing productions from many external facilities, etc. The project lasted for over one year, and the results are a much improved audio quality and a more balanced loudness consistency throughout all the channels involved.
Convention Paper 7044 (Purchase now)

P10-3 Sound Levels of TV Advertisements Relative to the Adjacent Programs and Cross-National Comparison of the Way of Their Insertion into Programs—Eiichi Miyasaka, Akiko Kimura, Musashi Institute of Technology - Yokohama, Kanagawa, Japan
A couple of perceptual experiments were conducted in order to investigate the relationship between the physical sound levels of advertisements (CMs) and the corresponding auditory perception relative to the reference speech. Experiment 1 for three types of CMs aired in Japanese broadcasting with different sound levels show that all CMs sound louder than a reference speech irrespective of large sound level differences. Experiment 2 for three types of CMs with similar sound levels and the standard deviations show that some of them sound louder than the reference. Next, ways of insertion of CMs into programs were investigated for news programs broadcast in Japan, the UK, and the US. The results show that silent periods with different durations were commonly inserted between main programs and CMs in UK and in US, while no silent period was introduced in Japanese commercial broadcasting.
Convention Paper 7045 (Purchase now)

P10-4 Influence of Interaction on Perceived Quality in Audio Visual Applications: Subjective Assessment with n-Back Working Memory Task, II—Ulrich Reiter, Mandy Weitzel, Technische Universität Ilmenau - Ilmenau, Germany
The mechanisms of human audio visual perception are not fully understood yet. For interactive audio visual applications running on devices with limited computational power it is desirable to know which of the stimuli to be rendered in an audio visual room simulation have the greatest impact upon the perceived quality of the system. We have conducted experiments to determine the effect of interaction upon the precision with which test subjects are able to discriminate between different parameter values of auditory attributes. This paper details one of these experiments and compares different approaches for the analysis of the obtained data. The results show a noticeable bias toward faulty ratings during the involvement in a task, although the analyses using significance tests did not completely confirm this effect.
Convention Paper 7046 (Purchase now)

P10-5 On the Audibility of Comb Filter Distortions—Stefan Brunner, Hans-Joachim Maempel, Stefan Weinzierl, Technical University of Berlin - Berlin, Germany
Superpositions of delayed and undelayed versions of the same signal can occur at different stages of the audio transmission chain. Sometimes it is a deliberate measure to provide audio material with certain spatial or timbral qualities. Often it is a result of multiple microphone signals, sound reflections on walls or latencies in digital signal processing leading to comb-filter-shaped, linear distortions. The measurement of a hearing threshold for this type of distortion with its dependence on reflection delay, relative level, and the type of audio content can be the basis for boundaries in everyday recording practice below which undesired timbral distortions can be neglected. Therefore, a listening test was conducted to determine the just noticeable difference for three stimulus categories (speech, a snare drum roll, and a piano phrase) and different time delays between direct and delayed signal from 0.1 ms to 15 ms, equivalent to 0.03 to 5.15 m of sound path difference. The results show that comb-filter distortions can still be audible if the level of the first reflection is more than 20 dB lower than the level of the direct sound.
Convention Paper 7047 (Purchase now)

P10-6 VirtualPhone—A Rapid Virtual Audio Prototyping Environment—Nick Zacharov, Nokia Corporation - Tampere, Finland
As the complexity of mobile phones increases with the evolution of digital convergence, there is increased demand to ensure high audio quality for all applications. VirtualPhone is a graphical user interface based software environment allowing for the rapid prototyping of mobile phone audio and its subsequent calibrated auralization. This paper describes the framework of the VirtualPhone application, illustrates its usage and performance compared to other conventional prototyping schemes.
Convention Paper 7048 (Purchase now)

P10-7 Evaluation of HE-AAC, AC-3, and E-AC-3 Codecs—Leslie Gaston, Richard Sanders, University of Colorado at Denver and Health Sciences Center - Denver, CO, USA
The Recording Arts Program at the University of Colorado at Denver and Health Sciences Center (UCDHSC) performed an independent evaluation of three audio codecs: Dolby Digital (AC-3 at 384 kbps), Advanced Audio Coding Plus (HE-AAC at 160 kbps), and Dolby Digital Plus (E-AC-3 at 224 and 200 kbps). UCDHSC performed double-blind listening tests during the summer of 2006, which adhered to the standards of ITU-R BS.1116 (that provides guidelines for multichannel critical listening tests). The results of this test illustrate a clear delineation between the AC-3 codec and the others tested. We will present the test procedures and findings in this paper.
Convention Paper 7049 (Purchase now)

P10-8 Perceptual Evaluation of Mobile Multimedia Loudspeakers —Gaetan Lorho, Nokia Corporation - Helsinki, Finland
An experiment was conducted to compare the perceptual characteristics of stereo loudspeaker systems found in mobile multimedia devices. An individual vocabulary development approach was employed for this descriptive analysis. Ten systems and five musical programs were selected for the experiment. Sixteen listeners developed their own set of attributes in three hours and performed a comparative evaluation of the ten systems for several program items using the attribute scales they developed. A total of 111 attributes was generated in this experiment, which could be divided in several perceptual groups relating to spatial, timbral, loudness, sound disturbance and sound articulation aspects. The principle of this sensory profiling method is described and some results of the subjective experiment are presented.
Convention Paper 7050 (Purchase now)

P10-9 A Rapid Listening Test Environment—Helping Managers Make Better Decisions—Nick Zacharov, Nokia Corporation - Tampere, Finland
As the complexity of mobile phones increases with the evolution of digital convergence, there is increased demand to ensure high audio quality for all applications. This paper presents a set of software applications that allow for the rapid definition, administration, analysis, and reporting of listening tests without the need for extensive technical knowledge of the field. A through description of the concepts behind the client/server architecture of the software is presented followed by some example applications. Last, a performance comparison of listening tests performed using more traditional methods versus the presented method is made.
Convention Paper 7051 (Purchase now)