In This Section
Journal of the AES
2009 March - Volume 57 Number 3
Resynthesis of Sound Scenes on Wave-Field Synthesis from Stereo Mixtures Using Sound Source Separation Algorithms
Because the vast majority of musical recordings are preserved in two-channel stereo format, special upconverters are required in order to use advanced spatial reproduction formats, such as wave-field synthesis. This paper evaluates the subjective quality of synthesized acoustic scenes when using virtual sources that were extracted as separate tracks from stereo mixes. Although wave-field synthesis has its own artifacts, the degradation produced by using separated sources includes timbre modification, burbling sounds, musical noise, and intersource residuals. However, masking effects make these artifacts less perceptible when the entire scene is being reproduced.
The means by which an individual distinguishes between (a) self-movement relative to a fixed external object and (b) a fixed sense of self relative to a moving object involves both sensory input and cognitive processes. The current study examines the cognitive influences of an auditory presentation on the illusion of motion. The illusion of self-motion was strongest when simulating multiple auditory objects of the type that are expected to be immobile: acoustic landmarks. The effect is strongest without visual cues, which can dominate if present. The addition of vibrotactile stimulation of the whole body was only selectively contributing to the experience of being in motion depending on the simulated auditory objects.
All-pass filters have been a central building block in artificial reverberation systems. The authors propose nested and interleaved combinations of such filters as an efficient way to produce reverberation architecture without a correspondingly high compute cost. The resulting dual all-pass filter approach compares favorably to that of embedded all-pass filters.
A universal design procedure has been developed for enhancing the low-frequency response of loudspeakers ranging from handset loudspeakers to large subwoofers. The procedure attempts to find the optimal parameters of a vented-box system on the basis of the vibration-absorber theory. Simulations and experiments were used to validate the optimal design. Design charts and constrained optimization facilitate the design of the acoustic enclosure. Although limitations do not allow for accurate prediction of responses below 100 Hz, the comparison between closed- and vented-box performance correlates well with the desired bass extension.
Standards and Information Documents
AES Standards Committee News
Audio file interchange; storage of polyester tape; life expectancy of CD-ROM; synchronization of digital audio equipment in studio operations
Music Information Retrieval (MIR) is the technology behind systems capable of searching, analyzing, and recommending audio content. However, this technology is still less than ten years old. With the vast amount of digitally-encoded music now available to potential users, there is an increasing demand for systems that recommend songs, enable searching for tunes by humming, and facilitate the browsing of large archives. These are just a few of the possible applications for MIR, many of which are finding their way into everyday devices such as mobile phones. Devices have grown rapidly in their processing power and features, and there has been an explosion in the availability of digital media content on the Internet. At the recent AES 125th Convention, Jay LeBoeuf from Imagine Technologies chaired a workshop of experts to discuss research directions and applications of MIR technology. Among them were Markus Cremer of Gracenote, Matthias Gruhne of Fraunhofer Institute for Digital Media Technology, Tristan Jehan of The Echo Nest, and Keyvan Mohajer of Melodis Corporation.
126th Convention Preview, Munich
126th Convention Exhibit Previews
14th Regional Convention, Tokyo, Call for Papers