Reports on Progress:

Setting up the Equipment

In experiments five main loudspeakers were arranged according to the ITU-R BS.775 Recommendation (see figure below). Distance between the loudspeakers and the optimum listening position was equal to 2.1 m. The subwoofer was located behind the centre loudspeaker about 20 cm from the wall.

figure: BS775

Loudspeaker set-up used in experiments based on the ITU-R BS. 775 Recommendation

A TV monitor (42" plasma display, 16:9 aspect ratio) was used for visual presentation. The distance between the TV monitor and the listener was set to 4 H, where H is the height of the viewing area (this distance conformed to recommendations). It was not easy to decide where to install the TV monitor with respect to the centre loudspeaker. Several options were informally tested. Eventually it was decided to set up the TV monitor below the centre loudspeaker and to fix the centre loudspeaker higher than the remaining main channels. It was the most comfortable arrangement for the listeners/viewers. To minimise the phase distortions at high- and mid- frequencies due to the different distance between the listener and the tweeters of the front loudspeakers, the centre loudspeaker was installed upside down in such a way that the tweeters were aligned at the same height (see figure below).

figure: tv

Set-up of the centre loudspeaker with respect to the TV monitor and other loudspeakers