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P24 - Psychoacoustics, Perception, and Listening TestsTuesday, May 23, 09:00 — 12:40
Chair: Gaetan Lorho, Nokia Corporation - Helsinki, Finland
P24-1 Auditory Scene Synthesis for Distributed Audiences in E-Learning Applications—Gavin Kearney, Dermot Furlong, Trinity College - Dublin, Ireland
The enhancement of learning processes through electronic presentation has led to the development of e-Learning environments, which merge traditional classroom instruction with teleconference capabilities. One aspect of such presentations is the correct localization of both stationary and mobile sound sources for all audience members with the video data on a teleconference screen. Research into conventional sound reinforcement solutions shows how systems based on stereophonic principles fail in this regard. Furthermore, sound systems such as Delta Stereophony and Wave Front Synthesis, which provide the accurate wavefronts required for correct localization, are found to be uneconomic for application to e-Learning classroom environments. A solution to this localization problem is presented as a 5-speaker frontal line-array and its effectiveness is verified through accurate simulator and localization tests. A physical implementation of the system is also presented for subjective evaluation.
Presentation is scheduled to begin at 09:00
Convention Paper 6816 (Purchase now)
P24-2 The Effect of Loudspeaker Frequency Bandwidth Limitation and Stereo Base Width on Perceived Quality—Gaetan Lorho, Nokia Corporation - Helsinki, Finland
The effect of frequency bandwidth limitation and stereo base width on listeners’ preference for loudspeaker reproduction of music and movie sound was studied. Various combinations of high and low frequency band limitation were considered for near-field monophonic and stereophonic loudspeaker reproduction. Two loudspeaker configurations with a reduced stereo base width representative of mobile multimedia systems were also included in this experiment to investigate the perceived effect of a stereo enhancement algorithm. The results of this study indicate that untrained listeners consider low-frequency content to be more important than high-frequency content or stereophony in their preference judgments. For cases where the optimal stereo reproduction was preferred to the monophonic and reduced stereo base setups, a significant improvement in preference was found with the stereo enhancement systems.
Presentation is scheduled to begin at 09:20
Convention Paper 6817 (Purchase now)
P24-3 Spatial Character and Quality Assessment of Selected Stereophonic Image Enhancements for Headphone Playback of Popular Music—Atsushi Marui, William Martens, McGill University - Montreal, Quebec, Canada
The effects of selected stereophonic image enhancement algorithms on perceived spatial character and quality of headphone playback for popular music was investigated for a sampling of program material typical of conventional multitrack mixes. Preference ratings were made for the auditory images resulting from three enhancement algorithms in comparison with the original PCM recordings of nine short musical programs. A perceptual coding (MP3) of the original recordings was also presented, making a total of five versions to be compared for each musical program. In addition, ratings were collected on a perceptual attribute identified herein as Ensemble Stage Width (ESW). Applied algorithms had significant effects on both preference and ESW ratings, regardless of whether expensive or inexpensive headphones were used in the listening tests.
Presentation is scheduled to begin at 09:40
Convention Paper 6818 (Purchase now)
P24-4 Designing a Spatial Audio Attribute Listener Training System for Optimal Transfer—Rafael Kassier, Tim Brookes, Francis Rumsey, University of Surrey - Guildford, Surrey, UK
Interest in spatial audio has increased due to the availability of multichannel reproduction systems for the home and car. Various timbral ear training systems have been presented, but relatively little work has been carried out into training in spatial audio attributes of reproduced sound. To demonstrate that such a training system is truly useful, it is necessary to show that learned skills are transferable to different settings. Issues relating to the transfer of training are examined; a recent study conducted by the authors is discussed in relation to the level of transfer shown by participants, and a new study is proposed that is aimed to optimize the transfer of training to different environments.
[Associated Poster Presentation in Session P29, Tuesday, May 23, at 14:00]
Presentation is scheduled to begin at 10:00
Convention Paper 6819 (Purchase now)
P24-5 Evaluation of Loudness in a Room Acoustic Model—Yi Shen, Konstantinos Angelakis, Technical University of Denmark - Kgs. Lyngby, Denmark
The equal loudness contours were measured using an analytical model, which was constructed for rectangular rooms based on the Kuttruff’s room acoustic model. A stimulus can be presented through the room acoustic model to the subjects via headphones. The results are in very close agreement with measurements in a real room. Two additional experiments were conducted to study the loudness as a function of reverberation time for different types of stimuli. The results showed that the effect of reverberation on loudness is negligible for a stationary stimulus. On the other hand, for an impulse train, loudness depends on both the reverberation time of the test room and the repetition frequency of the stimulus.
[Associated Poster Presentation in Session P29, Tuesday, May 23, at 14:00]
Presentation is scheduled to begin at 10:20
Convention Paper 6820 (Purchase now)
P24-6 Effect of Direction on Loudness for Wideband and Reverberant Sounds—Ville Pekka Sivonen, Aalborg University - Aalborg, Denmark, and Brüel & Kjær Sound & Vibration Measurement A/S, Nærum, Denmark; Wolfgang Ellermeier, Aalborg University - Aalborg, Denmark
The effect of incidence angle on loudness was investigated for wideband and reverberant sounds. In an adaptive procedure, five listeners matched the loudness of a sound coming from five incidence angles in the horizontal plane to that of the same sound with frontal incidence. The stimuli were presented to the listeners via individual binaural synthesis. The results confirm that loudness depends on a sound incidence angle, as it does for narrow-band, anechoic sounds. The directional effects, however, were attenuated with the wideband and reverberant stimuli used in the present investigation.
Presentation is scheduled to begin at 10:40
Convention Paper 6821 (Purchase now)
P24-7 Investigations in Real-time Loudness Metering—Gilbert Soulodre, Michel Lavoie, Communications Research Centre - Ottawa, Ontario, Canada
There has been much research in the past few years on loudness perception and metering. Recently, the authors developed an objective loudness algorithm that accurately measures the perceived loudness of mono, stereo, and multichannel audio sequences. The algorithm provides a single loudness reading for the overall audio sequence. In broadcast, film, and music applications it is desirable to have a real-time loudness meter that can track the loudness of the audio signal over time. The new meter would be used in conjunction with existing metering methods to provide additional information about the audio signal. In the present paper the requirements for such a meter are examined and new subjective testing methods are devised to help in the development and evaluation of a new meter.
[Associated Poster Presentation in Session P29, Tuesday, May 23, at 14:00]
Presentation is scheduled to begin at 11:00
Convention Paper 6822 (Purchase now)
P24-8 Measuring the Threshold of Audibility of Temporal Decays—Andrew Goldberg, Genelec Oy - Iisalmi, Finland; Helsinki University of Technology, Espoo, Finland
A listening test system designed to measure the threshold of audibility of the decay time of low frequency resonances is described. The system employs the Parameter Estimation by Sequential Testing (PEST) technique, and the listening test is conducted on calibrated headphones to remove factors associated with the listening environment. Program signal, replay level, and resonance frequency are believed to influence decay time threshold. A trial the listening test shows that the system reveals realistic results but the temporal resonance modeling filter requires some adjustment to remove audible nonmodal cues. Transducer limitations still affect the test at low frequencies and high replay levels. Factors for future large-scale listening tests are refined. Early indications are that temporal decay thresholds rise with reduced frequency and SPL.
[Associated Poster Presentation in Session P29, Tuesday, May 23, at 14:00]
Presentation is scheduled to begin at 11:20
Convention Paper 6823 (Purchase now)
P24-9 The Influence of Impulse Response Length and Transition Bandwidth of Magnitude Complementary Crossover on Perceived Sound Quality—Iva Djukic, Institute Mihailo Pupin - Belgrade, Serbia and Montenegro; Dejan Todorovic, RTS-Radio Beograd - Belgrade, Serbia and Montenegro; Ljiljana D. Milic, Institute Mihailo Pupin - Belgrade, Serbia and Montenegro
In this paper a special type of magnitude complementary IIR filter pair with variable transition bandwidth and impulse response length was used in order to examine the effects of these two characteristics on subjective perception of the reproduced sound. Two types of listening tests were performed. In the first type of tests the sum of crossover outputs was compared to the original signal. In the second type of tests the IIR filter pairs were compared among themselves, as well with linear phase magnitude complementary FIR filter pairs as a reference. The results of the tests show that overall differences are not significant. It was found that considered filters are suitable for loudspeaker crossover applications.
[Associated Poster Presentation in Session P29, Tuesday, May 23, at 14:00]
Presentation is scheduled to begin at 11:40
Convention Paper 6824 (Purchase now)
P24-10 Perception of Simultaneity and Detection of Asynchrony between Audio and Structural Vibration in Multimodal Music Reproduction—Kent Walker, William L. Martens, Sungyoung Kim, McGill University - Montreal, Quebec, Canada
In music reproduction incorporating haptic display there is a need to know the human observer’s tolerance for asynchrony between presentations of audio (airborne vibration) and hapti content (in this case whole-body vibration). Two methods for measuring the human tolerance for such audio-haptic asynchrony were employed in experiments using recorded musical instrument sound as stimuli: judgments of the time order of arrival of airborne versus structure-borne vibration, and judgments of subjective simultaneity that required no report of which component arrived first. Optimal intermodal delay values derived from the time order judgments were related to the direct judgments of simultaneity for the same set of stimuli.
Presentation is scheduled to begin at 12:00
Convention Paper 6825 (Purchase now)
P24-11 Computational Two-Channel ITD Model—Ville Pulkki, Helsinki University of Technology - Helsinki, Finland
Recently, the Jeffress model of localization has been questioned in neurophysiological studies, and a two-channel ITD model has been proposed. In this paper a simple computational implementation of the two-channel ITD model is presented, which models the ITD decoding based on neurophysiological data, although computationally in a very simple way. The model fits almost perfectly to the neurophysiological data recorded from a guinea pig and matches at least qualitatively with psychoacoustic data.
Presentation is scheduled to begin at 12:20
Convention Paper 6826 (Purchase now)
