In This Section
Journal of the AES
2011 June - Volume 59 Number 6
Hiding inaudible data in an audio signal (watermarking), which can be useful for transmitting metadata and inserting copyright identification, is based on taking advantage of the complexity of human perception. In the proposed approach, data is embedded using the polarity of reverberation (echoes) that is added to the high frequencies. A detector uses the sum and difference of the high frequencies in the two channels to extract the data. Average data rates of 22 bps were achieved. The approach was robust with additive noise at 30 dB SNR. In addition MP3, AAC encoding, sample-rate conversion, pitch shifting, and frame misalignment did not destroy the information.
Designing and evaluating a product’s sound during the conceptual phase is both more effective and efficient. Many products produce sounds that are intentional (such as the ring of a phone) and as artifacts (such as the motor noise of a vacuum cleaner). In most cases, the sonic aspects of a product are considered after the design is mostly complete where the choices are limited. A tool that allows sounds to be “sketched” is suggested as a means for industrial designers to begin the sound design process at the earliest stages. A preliminary analysis suggests that an inexperienced sound designer can successfully sketch a sound with the appropriate adjectives.
Methods are presented for transforming signals from a specific microphone array into those that would have been recorded at a different array at the same location. In a nonparametric method, beams are formed at fixed directions using a low-sidelobe beamforming technique. In a parametric method, beams are formed adaptively using a direction-finding algorithm. In a hybrid method, point source signals and spatially diffuse residual signals are separately processed. Results show good agreement between measured and synthesized array outputs with signal correlation coefficients near 1.0 for all three methods. Informal listening tests confirmed effective sound field resynthesis.
User interfaces of audio tools and processors can be difficult for novices to use because technical parameters provide little guidance about their sonic manifestation. Borrowing a technique from psychoacoustics, the authors explore an efficient means for mapping users’ descriptors (target adjectives) to technical parameters. Weighting functions are created based on the relative influence of a parameter in influencing the adjective descriptor, such as warm, bright, and full. This approach was tested on two common types of processing: equalization and reverberation. Despite the relative simplicity of the approach, the results are promising.
Corrections to “Multiple-Loudspeaker Playback of Stereo Signals”
Standards and Information Documents
AES Standards Committee News
Digital audio connector; digital audio measurements; polarity; loudspeaker patch connectors; microphone measurement and characterization; audio connectors
43rd Conference Preview, Pohang
Mastering engineers gathered to discuss the relationship between art, perception, and technology in two workshops held last year at the AES 129th Convention in San Francisco. The first of these, chaired by Michael Romanowski, welcomed an expert panel consisting of Gavin Lurssen, Andrew Mendelson, Joe Palmacio, and Mike Wells.