Last Updated: 20050406, meiMonday, May 30, 15:00 — 16:30
Z8-1 Spatial Sound Localization Measures from a Dummy Head with a Loudspeaker Array in Anechoic Chamber—Elena Blanco-Martín, Juan José Gómez-Alfageme, Soledad Torres-Guijarro, Francisco Javier Casajús-Quirós, Universidad Politécnica de Madrid - Madrid, Spain
In videoconference systems composed of microphone and loudspeaker arrays, a cue of subjective sound quality is the ability to locate the sound source. A ten-loudspeaker array and a dummy head are set up in an anechoic chamber. The field sampled by the microphone array is simulated by a narrow band source located at different azimuths in a virtual chamber. The computed signals are emitted by the loudspeakers and the binaural signal recorded with the dummy head is processed. Some improvements have been made compared with previous methods of azimuth estimation. An ellipsoidal head model is used to calculate the interaural time difference (ITD) giving better results than previous approaches. The estimation given by the ILD (interaural level difference) cue is used to avoid the ITD ambiguity at high frequencies.
Convention Paper 6456 (Purchase now)
Z8-2 Development of Objective Sound Quality Evaluation Method Based on Subjective Sound Quality Evaluation—Jongbae Kim, Ho-Young Sung, Joon-Hyun Lee, Sangil Park, Samsung Electronics Co. - Suwon, South Korea
Generally, evaluation of sound quality of audio systems or AV devices is accomplished through listening tests with groups of trained listeners, each having subjective views. But these kinds of methods often tend to give results that are distorted due to listening environments and personal preferences of the listeners. For these reasons, even though they are deeply related to the way listeners actually hear things, subjective listening tests contain problems such as inaccuracy and time/place dependency. By examining the correlation between objective measurable evaluation factors and subjective listening test items, this paper proposes an objective method for sound quality evaluation that is based on former subjective methods for audio systems and AV devices.
Convention Paper 6457 (Purchase now)
Z8-3 Speech Quality Prediction for Voice in Rooms—Stefan Brachmanski, Wroclaw University of Technology - Wroclaw, Poland
The methods for assessment of speech quality fall into two classes: subjective and objective methods. This paper includes an overview of selected methods of subjective listening measurements (ACR, DCR, speech intelligibility) recommended by ITU-T, ISO, Polish Standard, and the method of speech transmission quality evaluation called "modified intelligibility test with forced choice" (MIT-FC). The MIT-FC method provides fully automated measurement of speech intelligibility in rooms. The listener’s task is to select on a computer monitor which alternative, visually presented utterances was spoken. A computer application automatically calculates speech intelligibility and the factor of speech quality. There are two objective methods described in the paper: Articulation Index and the Hougast and Steeneken method (STI, RASTI). Experiments in which the methods were used are described. The results are compared with RASTI measurements.
Convention Paper 6458 (Purchase now)
Z8-4 Application of Different Time-Frequency Analysis to Psychoacoustic Description of Car Engine Noise—Gema Piñero, Maria de Diego, Alberto González, Laura Fuster, Andres Camacho, Universidad Politécnica de Valencia - Valencia, Spain
A new approach to the evaluation of subjective perception of car engine noise is presented in this paper. It makes use of different Time-Frequency (TF) methods that are applied to the calculation of some TF parameters of the noise signals, mainly related to energy variations. The analysis has been performed dividing the noise signals into two groups: low and high r.p.m. For each group of signals TF parameters have been computed and linearly combined through a multiple regression model in order to describe the most important psychoacoustic features of the noises: loudness, sharpness, and roughness. A very good fit of the calculated loudness using TF energies has been obtained, whereas sharpness and roughness have also achieved quite high correlation values in their respective analysis. Finally, conclusions about the ability of the proposed TF techniques to model psychoacoustic metrics are also given.
Convention Paper 6459 (Purchase now)
Z8-5 A Preliminary Investigation on the Subjective Evaluation of Church Acoustics Using Listening Tests—Francesco Martellotta, Politecnico di Bari - Bari, Italy
The paper describes the main steps of research investigating the relation between subjective assessment of listening conditions in churches and the main objective acoustic parameters. Measurements of binaural and B-format impulse responses were made in several churches and in different positions inside the same church. A listening room was designed and realized in order to carry out listening tests using a stereo-dipole configuration. Measured binaural IRs were crosstalk cancelled and then auralized with an anechoic motif. Paired comparisons were finally performed, asking a trained panel of subjects their preference.
Convention Paper 6460 (Purchase now)
Z8-6 Subjective Assessments of Real-Time Room Dereverberation and Loudspeaker Equalization—John Worley, Panagiotis Hatziantoniou, John N. Mourjopoulos, University of Patras - Patras, Greece
Formal subjective tests of real-time room dereverberation using complex smoothing were conducted to assess the robustness and the validity of the method under real sound reproduction conditions. For comparison, anechoic, inverse loudspeaker real-time filtering was also subjected to assessment to decouple improvements due to the complex smoothing inverse room filtering and mere equalization of the loudspeakers. Results derived from a multivariate analysis of variance (MANOVA) of the test data verify the conclusions detected in the past by the objective evaluation of the method, e.g., significant improvement in sound quality and immunity to real-time processing artifacts independently of room size and listener position.
Convention Paper 6461 (Purchase now)
Z8-7 Combining Visual and Acoustic Modalities to Ease Speech Recognition by Hearing Impaired People—Bozena Kostek, Piotr Dalka, Gdansk University of Technology - Gdansk, Poland
The aim of the research paper presented is to show a system that facilitates speech training for hearing impaired people. The system engineered combines both visual and acoustic speech data acquisition and analysis modules. The Active Shape Model method is used for extracting visual speech features from the shape and movement of the lips. The acoustic features extraction involves mel-cepstral analysis. Artificial Neural Networks are utilized as the classifier; feature vectors extracted combine both modalities of the human speech. Additional experiments with the degraded acoustic and/or visual information are carried out in order to test the system robustness against various distortions affecting the signals.
Convention Paper 6462 (Purchase now)
Z8-8 Objective and Subjective Evaluation of Digital Equalization Systems—Measurements of Resonances and Colorations—Vassilis "Bill" Tsakiris, Crystal Audiovideo - London, UK; Chris Orinos, Kostis Laskaris, Crystal Audio SA - Vrilissia, Greece
In this paper we get into the correlation of subjective with objective criteria in an attempt to automatically evaluate digital equalization systems. Although the method developed can be perfectly adapted in the case of loudspeaker evaluation, our main concern and motivation is the objective evaluation of digital equalization (EQ) systems that promise the undoing of loudspeaker and room artifacts by using different approaches. The really interesting issue about digital EQ systems is to develop some metrics in order to evaluate their performance in terms of frequency response flatness and spatial smoothness. Furthermore the tool that we have developed in MATLAB could be used in an optimization system in the DSP so as to control the EQ parameters aiming for an optimum overall frequency response.
Convention Paper 6463 (Purchase now)
Z8-9 Tuning of the Objective, Perceptual-Based Evaluation Methods of Compressed Speech and Audio Signals—Piotr Kozlowski, Andrzej B. Dobrucki, Wroclaw University of Technology - Wroclaw, Poland
This paper presents an almost final view for the research about objective methods, which use psychoacoustics knowledge for estimation of the quality of audio signals. The software written especially for this research is presented. This program allows for implementation of the different published methods for evaluation of the quality of perceptual coded audio signals. Protocols: PAQM, PSQM, NMR, PEAQ, PESQ have been implemented up to now. All of these algorithms are used for simulation of the auditory system. The software is open for addition next protocols as the plug-ins. There is a possibility to change and improve earlier published protocols. The authors proposed in earlier works how to improve objective protocols, e.g., by changing pitch scale or FFT parameters. Suggested tuning of internal parameters of signal processing, which improves results of objective evaluation, is presented. The criterion of optimization is difference between results of subjective and objective evaluation.
Convention Paper 6464 (Purchase now)
©2005 Audio Engineering Society, Inc.