Personal sound

Introducing more audio/video equipment (CD, DCC, TV, CD-I, etc.) into a room creates a new audio problem, one of multiple sound sources with multiple listeners. When different persons, denoted as A, B, C, etc., listen to different programs, denoted as ‘‘a,’’ ‘‘b,’’ ‘‘c,’’ person A experiences program ‘‘a’’ as sound and programs ‘‘b’’ and ‘‘c’’ as noise. Each person would prefer a high sound/noise (S/N) ratio at his listening position. In this contribution the situation of two persons working with their (multimedia) PCs in an office, or watching in a living room two TVs with accompanying sound, is considered. In order to obtain a specification, listening tests were done, which gave a desired S/N ratio of about 20 dB(B). In an anechoic environment such a specification is easily realized using a loudspeaker array to control the directivity. In a real (living) room this is not sufficient and active noise control (to decrease N) and active sound control (to increase S) are used, particularly in the low-frequency region. During the presentation at the conference, recordings will be reproduced of realized S/N ratios of 34 dB(B) in the anechoic room and of more than 20 dB(B) in a living room.