Authors: Van De Ven, Erik; Aarts, Ronald M.; Sommen, Piet C. W.
Cascading of stereo-base widening systems causes a deterioration of the listening performance. A solution to this problem is to cancel the widening effect before the signal is widened again. The main effect of stereo-base widening systems is to the effect on the phase difference. A model for the distribution of the phase difference of normal mixed stereo recordings is presented. Stereo recordings processed by a stereo-base widening system do not fit this model. An application of this property is illustrated with an example. This example can estimate the amount of widening of a particular widening system in an iterative blind way. At the same time it recovers the original audio signal.
Authors: Muraoka, Teruo; Nakazato, Tomoaki
The locations of loudspeakers were examined utilizing frequency-dependent interaural cross correlation (FIACC) for optimum sound-field recomposition in multichannel recording and reproduction processes. Experiments were conducted and sets of FIACC measurements compared, with one taken in an original sound field, the other in the reproduced sound field. Several sound-field reproduction methods using different microphone-array geometries and matching loudspeaker-array geometries were considered. The results presented support the ITU recommendation for loudspeaker arrangements in five-channel systems (BS.775-1).
Authors: Bouten, Jos; Van Rijsbergen, Mariska; Donkers, Simon
One of the main questions forensic tape authenticity investigations seek to answer is whether a recording on a given tape was produced using a given recorder in a claimed way. A technique that uses so-called ferrimagnetic garnet films, also known as Faraday crystals, makes it possible to take pictures showing the magnetic flux distribution on a tape in such detail that it enables a forensic investigator to answer questions that may arise about the correctness of the claims made. For an in-depth understanding of pictures of these flux distributions, a theory behind the visualization technique is necessary. The derivation of a theoretical transfer function of the visualization technique (spanning from a theoretical input signal to the actual luminance of the pictures) is described and one of a few experiments that were conducted to prove its validity is presented.
Authors: Czyzewski, Andrzej; Ciarkowski, Andrej; Kaczmarek, Andrzej; Kotus, Jozef; Kulesza, Maciej; Maziewski, Przemek
Algorithms for determining the wow distortion characteristic are proposed. These are the power-line-hum tracking algorithm, the high-frequency-bias tracking algorithm, and the algorithm based on an adaptive analysis of the center of gravity of the spectrum of the distorted signal. All of the algorithms presented allow a hardware- or software-based implementation.
Authors: Staff, AES
[Feature] There is growing interest in the use of high quality audio on mobile and handheld devices. In this article we summarize recent research on the use of 3-D audio in such systems as well as papers from a recent AES conference in Korea dealing with the delivery and implementation of audio in mobile devices.
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