Convention Paper
An Investigation of Layered Sound
AES Convention 115 · Paper 5971 · October 2003
Abstract
A new technique for improving the spaciousness of reproduced sound has been investigated. The technique uses a combination of conventional Pistonic loudspeakers and Distributed Mode (DML) devices. Objective measurements have been made in a range of rooms and show that 'Layered Sound' affects parameters such as the Inter Aural Cross Correlation (IACC) and Lateral Energy Fraction as well as Centre Time and Early Decay Time. A number of conditions were investigated including listening room configuration and the relative sound levels of the loudspeakers. Limited subjective testing was carried out in order to ascertain the preferred relative intensities between the conventional and DML loudspeakers. This was confirmed to be optimal with the DMLs set within the range '5dB ± 3dB relative to the conventional stereo loudspeakers. The configuration of the listening room and the type of programme material (and recording technique) were also found to be significant factors. It is shown that over a range of conditions, Layered Sound enhances the perceived spaciousness, envelopment and clarity of reproduced sound, though some changes to the original stereo image were noted.
