| PAPERS | |
| High-Efficiency Low-Bl Loudspeakers (PDF-342KB) | |
| Ronald M. Aarts | 579 |
| As a critical design parameter of loudspeakers, especially at low frequencies, the force factor (Bl) determines the efficiency, impedance, sound level, temporal response, weight, and cost. High-Bl drivers have good efficiency but require large magnet systems. An alternative approach, which yields much lower cost and weight while preserving efficiency, uses low-Bl drivers. Prototype drivers with moving magnets and stationary coils were evaluated in a limited frequency range where efficiency is highest. This approach is suited to small portable loudspeakers. | |
| Discrimination of Group Delay in Clicklike Signals Presented via Headphones and Loudspeakers (PDF-478KB) | |
| Sheila Flanagan, Brian C. J. Moore, and Michael A. Stone | 593 |
| The threshold for detecting a frequency-dependent group delay in a clicklike sound was found to be independent of the center frequency of the delay (1-4 kHz) and was about 2 ms for presentation via headphones, or via loudspeakers in a nonreverberant room, for both binaural and monaural listening. In a reverberant room, thresholds increased, especially at low frequencies. These results suggest that the nonlinear phase response of loudspeakers is unlikely to have any audible effect in typical rooms. | |
| A Simple Hybrid Approach to the Time-Scale Modification of Speech (PDF-280KB) | |
| Don Knox, Nicholas Bailey, and Iain Stewart | 612 |
| Time-domain methods for stretching speech usually produce stuttering and roughness artifacts from mismatches at signal segment boundaries, especially with time-stretch ratios greater than 1.3. By combining time-domain and analysis-synthesis methods, a simple hybrid approach greatly reduced such artifacts at ratios greater than 1.6. Formal listening tests demonstrate an improvement in speech quality without incurring the complexity burden of full analysis-synthesis methods. The hybrid algorithm counters spectral mismatch and transient repetition. | |
| ENGINEERING REPORTS | |
| Directivity of Artificial and Human Speech (PDF-390KB) | |
| Teemu Halkorsaari, Markus Vaalgamaa, and Matti Karjalainen | 620 |
| Having an artificial mouth with the same radiating characteristics of real speakers provides a useful working tool for telecommunications research. Responses to three mouth simulators were compared to that of a group of test subjects in order to evaluate their similarity. More than 10 dB of difference was discovered in the two cases. The main contributors to the human radiating characteristics are mouth aperture size and effects of the upper body. | |
| LETTERS TO THE EDITOR | |
| Comments on "Low-DC-Resistance, Low-Frequency Loudspeaker Enclosures" | |
| Alex de Koster (PDF-78KB) | 632 |
| Author's Reply | |
| Carlo Zuccatti | 632 |
| CORRECTIONS | |
| Correction to "Low-DC-Resistance, Low-Frequency Loudspeaker Enclosures" | |
| Carlo Zuccatti (PDF-78KB) | 632 |
| STANDARDS AND INFORMATION DOCUMENTS | |
| AES Standards Committee News (PDF-101KB) | 633 |
| High-resolution multichannel digital interface (HRMAI); digital measurements; digital interfacing; file transfer; transfer technologies; microphones; listening tests | |
| FEATURES | |
| 118th Convention Report, Barcelona (PDF-2.4MB) | 642 |
| Exhibitors (PDF-300KB) | 658 |
| Program (PDF-650KB) | 661 |
| 119th Convention Preview, New York (PDF-630KB) | 714 |
| Exhibit Previews (PDF-1.3MB) | 716 |
| High-Density Optical-Disk Formats (PDF-515KB) | 749 |
| High-Resolution Audio in an Age of Universal Playback (PDF-102KB) | 754 |
| DEPARTMENTS | |
| Reviews of Acoustical Patents (PDF-362KB) | 636 |
| News of the Sections (PDF-252KB) | 756 |
| Sound Track (PDF-86KB) | 762 |
| Upcoming Meetings (PDF-97KB) | 763 |
| Available Literature (PDF-97KB) | 763 |
| Membership Information (PDF-200KB) | 765 |
| Advertiser Internet Directory (PDF-209KB) | 767 |
| In Memoriam (PDF-124KB) | 775 |
| Sections Contacts Directory (PDF-122KB) | 777 |
| AES Conventions and Conferences (PDF-112KB) | 784 |
| EXTRAS | |
| Order Form for AES 118th Convention Papers (PDF-101KB) | |
| Cover & Sustaining Members List (PDF-66KB) | |
| AES Officers, Committees, Offices & Journal Staff (PDF-117KB) | |
