In response to requests from key broadcasters and production houses, including SKY, ITV, the BBC and RAI in Italy, DK-Technologies is launching the MSD100C Loudness, which it says is designed to tackle the vexed issue of the perceived loudness of audio signals.
As anyone who has ever reached for the TV volume control during a commercial break will know, today's sound processing can lead to remarkably high perceived sound levels without sound exceeding the maximum permitted signal peak levels.
DK-Technologies' new MSD100C Loudness is a standalone unit that incorporates ITU Recommendations BS.1770 and BS.1771, which specify the algorithms that should be used to measure audio programme loudness. It is able to display the loudness of the individual audio channels, as well as the sum of the left and right signals, and can be used in any broadcast or post production facility as a health check during production or prior to transmission.
Thomas Hansen, DK's technical director, said at launch: "There are many applications where it is necessary to measure and control the perceived loudness of audio signals. Examples of this include television and radio broadcast applications, where the nature and content of the programme material changes frequently. In these applications the audio content can continually switch between music, speech, and sound effects.
"Such changes in the content of the programme material can result in significant changes in subjective loudness. Moreover, various forms of dynamic processing are frequently applied to the signals, which can have significant effect on their perceived loudness."
Hansen added that the matter of subjective loudness is also of great importance to the music industry and in the production of commercials, where dynamic processing is commonly used to maximise the perceived loudness.
The MSD100C Loudness incorporates an algorithm that is recommended by ITU. This is based on an extension of the Leq(RLB) algorithm to cover stereo and monophonic audio signals. The actual unit provides accurate loudness matching of audio from a number of different sources and offers a selection of working modes, including fast mode for realtime viewing of loudness, integrated mode for measuring the loudness of a recorded section or the complete recording and gated mode for viewing loudness of audio material with long pauses, such as. golf tournaments.
With selectable digital and analogue stereo inputs, the unit displays left and right channel loudness as well as the summed loudness. It also delivers the information as a numeric readout. The meter uses the Loudness Units (LU) scale, covering a range from -18db to +9dB. It also features an audio vector oscilloscope, phase correlation meter displays, a full VGA colour display and VGA output for external display.
Due to ship by the end of the year, it will be available in a variety of languages and can be delivered with different scales to suit different broadcasters, while still maintaining the consistent loudness measurement as set out by the ITU.