Vibratory and Acoustical Factors in Multimodal Reproduction of Concert DVDs

Sound and vibration perception are always coupled in live music experience. Just think of a rock concert or hearing (and feeling) a church organ sitting on a wooden pew. Even in classical concerts kettledrum and double bass are sensed not only with our ears. The air-borne sound causes seat vibrations or excites the skin surface directly. For some instruments (e.g. an organ) structure-borne sound is transmitted directly from the instrument to the listener.

If concert recordings are played back with multimedia hi-fi systems at home, these vibratory information is missing in the majority of cases. This is due to low reproduction levels or to the limited frequency range of conventional loudspeakers. The audio signal on todays DVDs contains an additional channel for low frequency effects (LFE), which is intended for reproduction using a subwoofer. The generation of tactile components is still very restricted. An enhancement of such a systems might be possible using an electrodynamical shaker which generates whole body vibration (WBV) for a seated person.

This paper describes a system implementing this approach. The generation of a vibrotactile signal from the existing audio channels is analyzed. Different parameters during this process (amplitude of the vibration, frequency range) are examined in relation to their perceptual consequences using psychophysical experiments.