Loudness monitoring

Loudness monitoring of programme levels is needed in radio and television broadcasting, as well as in audio post production. Traditional methods of measuring signal levels such as the Peak programme meter, and VU meter do not give the subjectively valid measure of loudness which many would argue is needed to optimise the listening experience when changing channels or swapping disks.

The need for proper loudness monitoring is apparent in the loudness war that is now found everywhere in the audio field, and the extreme compression that is now applied to programme levels, which ruins audio quality.

Loudness meters

Meters have been introduced that aim to measure the human perceived loudness by taking account of the equal-loudness contours and other factors, such as audio spectrum, duration, compression and intensity. One such device was developed by CBS Laboratories in the 1980s. Complaints to broadcasters about the intrusive level of interstitials programs (advertisements, commercials) has resulted in projects to develop such meters, that are rapidly going to become fundamental tools for loudness monitoring in the broadcast industry. Based on loudness metering, many manufacturers have developed real-time audio processors that adjust the audio signal to match a specified target loudness level that preserves volume consistency at home listeners.