Download Entire Journal (4.6MB)
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| Volume 51 Number 9 | 2003 September |
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CONTENT Download Entire Journal (4.6MB) |
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| In Memoriam: Patricia Macdonald (PDF-21K) Roger K. Furness | 779 |
| PAPERS | |
| Effects of Down-Mix Algorithms on Quality of Surround Sound (PDF-163K) | |
| Slawomir K. Zielinski, Francis Rumsey, and Søren Bech | 780 |
| When channel limitations prevent the transmission of a full 5.1 surround mix, there are many options for converting to a lesser number of channels using down mixing. Listeners were asked to evaluate eight different algorithms from two listening positions in terms of preferences rather than quality. Unfortunately, different audio cases produced variations in the conclusion about optimum. The presence of a video picture influenced the experience of reduced audio channels. | |
| Comment on this paper | |
| A Study on Head-Shape Simplification Using Spherical Harmonics for HRTF Computation at Low Frequencies (PDF-118K) | |
| Yufei Tao, Anthony I. Tew, and Stuart J. Porter | 799 |
| Using a simplified shape for the human head in computing head-related transfer functions (HRTFs) produces errors in the calculated pressures on the surface. A model of a head can be represented as a series of spherical harmonics. This study computes the errors in acoustic pressure that result from truncating the series, which corresponds to low-pass shape filtering. These shape errors follow the corresponding pressure errors for frequencies below 3 kHz. Harmonics to order 11 are sufficient for the low frequencies representation of a head. Beyond order 14 there is no additional improvement. | |
| Comment on this paper | |
| Differences in Performance and Preference of Trained versus Untrained Listeners in Loudspeaker Tests: A Case Study (PDF-271K) | |
| Sean E. Olive | 806 |
| The audio industry makes many assumptions about the appropriateness of various quality testing methods, but there have not been any significant studies to validate these assumptions. The choices are reduced to using trained listeners, who are efficient and discriminating, or untrained listeners, who are more representative of the user population. This 18-month study shows that trained listeners produce the same conclusion as 268 untrained listeners when evaluating loudspeakers. | |
| Comment on this paper | |
| Objective Measures of Listener Envelopment in Multichannel Surround Systems (PDF-350K) | |
| Gilbert A. Soulodre, Michel C. Lavoie, and Scott G. Norcross | 826 |
| Predicting the degree of listener envelopment is more complex than the traditional measures of lateral energy after the first 80 ms. This detailed study shows that the transition threshold between early and late energy is frequency-dependent. In addition, the loudness of the lateral energy is equally important. A new objective measure is proposed with a very high correlation between perceived envelopment and the calculated metric. | |
| Comment on this paper | |
| LETTERS TO THE EDITOR | |
| "More Comments on President's Message and Comments" (PDF-6K) John Woodgate | 841 |
| STANDARDS AND INFORMATION DOCUMENTS | |
| AES Standards Committee News (PDF-17K) | 842 |
| Sampling frequencies; digital audio synchronization; preservation and restoration of recordings; loudspeaker modeling and measurement | |
| FEATURES | |
| 23rd Conference Report, Copenhagen (PDF-1.6MB) | 846 |
| Digital Rights Management (PDF-382K) | 855 |
| 25th Conference, London, Call for Papers (PDF-16K) | 871 |
| DEPARTMENTS | |
| News of the Sections (PDF-274K) | 861 |
| Sound Track (PDF-69K) | 865 |
| New Products and Developments (PDF-72K) | 867 |
| Upcoming Meetings (PDF-30K) | 868 |
| Available Literature (PDF-85K) | 869 |
| Membership Information (PDF-86K) | 872 |
| Advertiser Internet Directory (PDF-81K) | 873 |
| Sections Contacts Directory (PDF-33K) | 874 |
| AES Conventions and Conferences (PDF-47K) | 880 |
| EXTRAS | |
| Cover & Sustaining Members List (PDF-33K) | |
| VIP List & Editorial Staff (PDF-27K) | |
| Ads In This Issue (HTML) | |