In This Section
Journal of the AES
2009 April - Volume 57 Number 4
In order to study the homogeneity of the sound field in relatively small rooms, four different configurations varying in acoustic treatment were tested. Two of the configurations used specially constructed sidewall panels for scattering sound, while the other two used mostly sound-absorbing materials. A homogeneous sound field is best achieved with extensive use of diffusive elements. Room treatment had a stronger influence on the sound field than the position of measurement.
A simulated binaural room impulse response was created by convolving a measured head-related transfer function with a hybrid image-source model having stochastic scattering from secondary sources. Listeners using headphones in subjective tests found that measured and simulated room impulse responses had equivalent localization accuracy. This study confirms that the ability to localize sound sources is closely linked to the ratio of direct-to-reverberant energy rather than the reverberation time.
The separation of tonelike and noiselike components within an audio signal is important for many signal processing applications, such as codecs employing a psychoacoustic criterion. Detection of tonal components allows for the creation of tonal tracks, which have specific masking properties. Conventional tonality estimation procedures are not well suited for modulated components that are typically found in music with vibrato and tremolo. In the proposed method, the analysis simultaneously uses a tonality metric based on both historic frames and spectral bins. The results for various metrics are compared.
When comparing loudspeakers and trying to eliminate the influence of their location, problems arise due to listeners’ short auditory memory. But if a virtual loudspeaker in a virtual room using headphones was equivalent to the real environment, comparison testing would avoid the problem of memory. Switching could be done instantaneously. Subjective tests showed that the quality of virtual loudspeakers depended highly on the test signal and upon the difficulty of creating accurate room- and head-related transfer functions at high frequencies. Nevertheless, virtualized loudspeakers can be imperceptible from reality in many cases.
Standards and Information Documents
AES Standards Committee News
Peak flutter; serial Multichannel Audio Digital Interface (MADI); digital audio over ATM networks; loudspeaker polar measurements
A number of companies now offer audio networking solutions designed for professional applications, based on the ubiquitous Ethernet standard. These systems are capable of delivering many audio channels over long distances at relatively low cost, with all the advantages of traditional data networks such as redundant capacity, routing, and reconfigurability. A panel of networking professionals introduced the features and benefits of this technology in a workshop held at last year’s 125th Convention in San Francisco.
35th Conference Report, London
36th Conference Preview, Dearborn
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