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| Volume 51 Number 1/2 | 2003 January/February |
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CONTENT Download Entire Journal (12.1MB) |
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| PAPERS | |
| Analysis of Traditional and Reverberation-Reducing Methods of Room Equalization (PDF-2.9MB) | |
| Louis D. Fielder | 3 |
| Unlike the traditional approach to room equalization, which compensates for the steady-state spectral effects, a true equalization method will become a dereverberator. Such an approach simultaneously removes the acoustic properties of the reproduction environment in both the frequency and time domains. It is a very difficult problem. Although the proposed solution proves to be impractical when employed in a real application, the analysis illuminates several critical criteria for evaluating any solution. New psychoacoustic metrics successfully predicted those degradations that made the system unacceptable. | |
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| Kautz Filters and Generalized Frequency Resolution: Theory and Audio Applications (PDF-1.3MB) | |
| Tuomas Paatero and Matti Karjalainen | 27 |
| Most audio signal processing filters use a basic building block containing a delay or a pole, but other choices of orthonormal functions include the use of an all-pass block. When using this type of block, the resulting structures, called Kautz filters, readily allow frequency warping. Although this approach has been overshadowed by the more traditional methods, the authors show that lower order filters are needed when applied to loudspeaker equalization, room response modeling, and guitar body acoustics. The design phase is more complex, but there is no additional computation load at run time. | |
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| Horn Acoustics: Calculation through the Horn Cutoff Frequency (PDF-568K) | |
| Peter A. Fryer | 45 |
| The author reconsiders the mathematical approach to analyzing exponential horn loudspeakers above and below the cutoff frequency. This work provides a more solid foundation for the simplified methods of partitioning the mathematics into two regions with different assumptions in each one. By introducing a tiny amount of acoustic loss into the model, the mathematics no longer break down when traversing the transition region at cutoff. The results agree with measured data. | |
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| Modified Discrete Cosine Transform-Its Implications for Audio Coding and Error Concealment (PDF-268K) | |
| Ye Wang and Miikka Vilermo | 52 |
| This study of the modified discrete cosine transform (MDCT) explores the implications of audio coding and error concealment from the perspective of Fourier frequency analysis. Subjective coding quality and the tolerance to missing or repeated compressed data blocks often produce contradictory requirements in real applications. Tradeoffs involve the selection of window-sized crossfade transitions between blocks and perception of uncancelled alias components. | |
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| CORRECTIONS | |
| Correction to: "On the Use of Time-Frequency Reassignment in Additive Sound Modeling" (PDF-8K) | |
| Kelly Fitz and Lippold Haken | 62 |
| STANDARDS AND INFORMATION DOCUMENTS | |
| AES Standards Committee News (PDF-136K) | 63 |
| MADI; loudspeaker components; peak flutter; tape storage; CD-ROM life; loudspeaker polar data; digital input-output interfacing; digital synchronization; media storage and handling; library and archive systems; forensic audio; audio connectors; shielding and EMC; audio over IEEE 1394 | |
| FEATURES | |
| 114th Convention Preview, Amsterdam (PDF-3.0MB) | 76 |
| Calendar (PDF-28K) | 78 |
| Exhibitors (PDF-736K) | 79 |
| Exhibit Previews (PDF-1.1MB) | 81 |
| Virtual and Synthetic Audio (PDF-156K) | 93 |
| 115th Convention, New York, Call for Papers (PDF-12K) | 112 |
| DEPARTMENTS | |
| News of the Sections (PDF-136K) | 99 |
| Upcoming Meetings (PDF-136K) | 104 |
| Sound Track (PDF-12K) | 105 |
| Available Literature (PDF-144K) | 106 |
| Membership Information (PDF-32K) | 108 |
| Advertiser Internet Directory (PDF-32K) | 109 |
| In Memoriam (PDF-32K) | 111 |
| Sections Contacts Directory (PDF-36K) | 114 |
| AES Conventions and Conferences (PDF-40K) | 120 |
| EXTRAS | |
| Cover & Sustaining Members List (PDF-28K) | |
| VIP List & Editorial Staff (PDF-28K) | |
| Ads In This Issue (HTML) | |