Surrounding line sources optimally reproduce diffuse envelopment at off-center listening positions.

Listener envelopment has previously been studied in the fields of room acoustics and multichannel sound reproduction. However, the potentially detrimental effect of a directional imbalance remains uninvestigated. This paper presents a listening experiment under anechoic conditions using a ring of 24 loudspeakers. Participants rated perceived envelopment for various loudspeaker subsets fed by incoherent noise signals. Off-center listening positions were simulated for different acoustic source models: -6 dB (point source), -3 dB (line source), or 0 dB attenuation for every doubling of distance. Only the line-source model preserved envelopment off-center, providing a low interaural level difference and a low interaural coherence as perceptual cues.