On the perception of apparent source width and listener envelopment in wave field synthesis

For several decades the measurement and technical description of the acoustical quality of a room is under investigation. Early research only dealt with single point measurements and estimated quality parameters for speech and music presentations by using simple models, like the early to late arriving sound energy ratio. Recent research also takes the spatial characteristics of a sound field into account, and a variety of parameters have been developed and investigated. The two most prominent features in concert hall acoustics are the apparent source width (ASW) and the listener envelopment (LEV). ASW describes the perceived width of the sound scene, while LEV is associated with the feeling of being enveloped by sound. However the role of ASW and LEV is still under discussion in the scientific community. In this paper ASW and LEV are investigated in the context of virtual acoustic environments (VAE) using wave field synthesis (WFS) for sound reproduction. The width of the sound source is modeled in different virtual rooms by using multiple closely spaced virtual sound sources. The perceptual parameters ASW and LEV are evaluated in listening tests with a total of 29 listeners.