Last Updated: 20050520, meiTuesday, May 31, 09:30 — 11:00
Z9-1 Near Optimal, Low Complexity Arithmetic Coding for Generalized Gaussian Sources—Florin Ghido, University Politechnica of Bucharest - Bucharest, Hungary
We propose a near optimal, asymmetrical, low complexity, block-based arithmetic coding algorithm for the prediction residuals produced by lossless or lossy audio compression algorithms. The analysis of real-world prediction residuals motivates the use of a modified two-sided continuous generalized Gaussian distribution, pdf(x)=c(p,s)*exp[-(|x|/s)^p], which is mapped to a discrete distribution. Closed form formulas and fast numerical estimates for the block parameters (p,s) are derived. Using a distribution property, precomputed probability tables are obtained for different values of p, independent of s. On average, we obtain 0.51% better compression than Golomb-Rice coding and only 0.17% worse than a high complexity, symmetrical coding algorithm. For very low complexity codes, an alternative coding algorithm can be used, employing only bit output, with comparable compression.
Convention Paper 6487 (Purchase now)
Z9-2 Modifications on NIST MarkIII Array to Improve Coherence Properties Among Input Signals—Maurizio Omologo, Claudio Bertotti, Luca Cristoforetti, Piergiorgio Svaizer, ITC-irst - Povo (Trento), Italy; Luca-Giulio Brayda, Institut Eurecom - Sophia Antipolis, France
This paper describes an activity that allowed realization of a modified NIST MarkIII array. This system is able to acquire 64 synchronous audio signals at 44.1 kHz and is primarily conceived for far-field automatic speech recognition and speaker localization. Preliminary experiments conducted on the original array had showed that coherence among a generic pair of signals was affected by a bias due to common mode electrical noise, which turned out to be detrimental for time delay estimation techniques applied to co-phase signals or to localize speakers. A hardware intervention was realized to remove each internal noise source from analog modules of the device. The modified array provides a quality of input signals that fits results expected by theory.
Convention Paper 6488 (Purchase now)
Z9-3 The History of the Tonmeister’s Technique at the "Lenfilm" Studio in Saint-Petersburg—Pavel Ignatov, Sound Producer - St. Petersburg, Russia
The first Russian film studio, created in Petrograd-Saint-Petersburg November 1918 played a significant role in the development of Russian cinematography (later called "Lenfilm"). Since its foundation "Lenfilm" has created more than 1500 sound films with such outstanding tonmeisters as I. Dmitriev, I. Volk, E. Nesterov, L. Obolensky, A. Shargorodsky, A. Bekker, B. Khutoriansky, etc. In 2001 "Lenfilm" carried out a project of technical re-equipment of sound recording equipment (i.e., Dolby SR, Dolby Digital, Dolby Digital Surround EX). The analysis of the development of tonmeister's art on "Lenfilm" over 80 years is the subject of this paper.
Convention Paper 6489 (Purchase now)
Z9-4 Design and Implementation of IIR Crosstalk Cancellation Filters Approximating Frequency Warping—Jae-woong Jeong, Junho Lee, Young-cheol Park, Yonsei University - Seoul, Korea; Jeong-Tae Kim, LG Electronics Inc. - Seoul, Korea; Dae-hee Youn, Yonsei University - Seoul, Korea
This paper presents a new method of designing crosstalk cancellers using low-order IIR filters. The design is accomplished by approximating FIR filters optimized in the warped frequency domain with IIR filters realized in the linear frequency domain. For practical implementations, the dewarped poles and zeros are properly paired and ordered to avoid instability. Also, considering finite word-length effects, we determine suitable number of data bits for the implementation systems. Our method provides an efficient tool to design a crosstalk canceller that has excellent performance over a wide range of frequencies and structural complexity comparable to conventional crosstalk cancellers. Simulation results confirm that the use of the proposed method significantly improves the channel separation over a wide range of frequencies.
Convention Paper 6490 (Purchase now)
Z9-5 Switching-Mode Audio Power Amplifiers with Direct Energy Conversion—Petar Ljusev, Michael A. E. Andersen, Technical University of Denmark - Kgs. Lyngby, Denmark
This paper presents a new class of switching-mode audio power amplifiers, which are capable of direct energy conversion from the AC mains to the audio output. They represent an ultimate integration of a switching-mode power supply and a Class-D audio power amplifier, where the intermediate DC bus has been replaced with a high frequency AC link. When compared to the conventional Class-D amplifiers with a separate DC power supply, the proposed single conversion stage amplifier provides a simple and compact solution with better efficiency and higher level of integration, leading to reduced component count, volume, and cost.
Convention Paper 6491 (Purchase now)
Z9-6 Balloons of Directivity of Real and Artificial Mouth Used in Determining Speech Transmission Index—Fabio Bozzoli, University of Parma - Parma, Italy; Michel Viktorovitch, Rieter Automotive Management AG - Winterthur, Switzerland; Angelo Farina, University of Parma - Parma, Italy
In room acoustics, one of the most used parameters for evaluating the speech intelligibility is the Speech Transmission Index (STI). The experimental evaluation of this STI generally employs an artificial speaker (binaural head) and listener (artificial mouth). In many cases (i.e., big rooms or system of telecommunications) the precision of directivity of an artificial mouth does not influence the result too much; on the contrary, inside cars—as well as in other cases—the shape of the whole balloon of directivity is important for determining correct and comparable values and different mouths give really different results in the same situation. For these reasons we have measured, in an anechoic room, the 3-D directivities of a statistical population of speakers. The postprocessing of the results enabled us to determine the average and the standard deviation of human speech directivity. These results constitute a valuable source of information for assessing the compliances of artificial mouth to reality.
Convention Paper 6492 (Purchase now)
Z9-7 Difference Level: An Objective Audio Parameter—Serge Smirnoff, SoundExpert - Moscow, Russia
This paper describes the objective parameter, called "Difference Level" that could be considered either as an extension of THD for nonperiodic signals, or as one of the estimations of a widely used difference signal. It could be used for instrumental measurements of signal degradation in various audio circuits and for psychoacoustic research. Infinite grade impairment scale and corresponding method for measurements of perceived audio quality based on this parameter is also proposed.
Convention Paper 6493 (Purchase now)
Z9-8 An Easy to Use Import-Export Data Format Specification for Response Type Data—Joerg Panzer, Consultant - Salgen, Germany; Lampos Ferekidis, Consultant - Barsinghhausen, Germany
This paper describes the intention, concept, and definition of a new specification for a data transfer protocol. The transfer typically originates from a measurement device or simulation package and is collected at a processing and documentation tool. To make this exchange as comfortable as possible it seems necessary to supply a range of control settings that describe the meaning and arrangement of the data values within the dataset. The layout of the specification strongly supports 3-D measurement situations, such as directivity measurements, and generally parameterized sets of data. The format of the protocol is easy to read, flexible, and straightforward to implement.
Convention Paper 6494 (Purchase now)
Z9-9 New HRTFs (Head Related Transfer Functions) for 3-D Audio Applications—Youngtae Kim, Samsung Advanced Institute of Technology (SAIT) - Yongin, Korea; Sunmin Kim, Samsung Electronics Co., Ltd. - Suwon, Korea; Jungho Kim, Samsung Advanced Institute of Technology (SAIT) - Yongin, Korea; Joonhyun Lee, Sang-il Park, Samsung Electronics Co. - Ltd., Suwon, Korea
An extensive database of HRTFs (Head Related Transfer Functions) has been established in order to work with high-quality 3-D acoustic appliances. The basic specifications of the measurement presented are a spatial resolution of 10° in elevation angles (ranging from -40° to 90°) and uniform spatial resolution of 5° in azimuth angles. The distance from the measurement sources to the center of the dummy head is 2 m, the sampling frequency is 48 kHz, and the quantization depth is 24-bits. The data is presented for three arrangements of pinna models (large, small, and no pinna), which were combined with the open and blocked ear canal cases to give a total of six sets of measurements. The comparison of the data with the database provided by the CIPIC (the Center of Image Processing and Integrated Computing) Interface Laboratory (U.C. Davis, California, USA) are in agreement. The database may contribute to show promise of providing useful applications of 3-D sound.
Convention Paper 6495 (Purchase now)
©2005 Audio Engineering Society, Inc.