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Posted by on Feb 6, 2013 | 4 comments

Loudness and Metering (Part 1)

Guest contribution by Owen Green

[This is the first of a two part series on loudness, mixing, metering and the new ITU loudness spec]

Understanding the complex relationship between sound level and perceived loudness turns out to be very important to us as designers of sound for a number of reasons:

  • Our perception of loudness is not constant (or even remotely linear) at different frequencies, so it is possible to have high level signals that nonetheless sound weak (and vice versa) depending on their frequency content.
  • The levels at which we monitor in the studio have an impact on how we hear our work, and consequently on how the work translates to different spaces and systems, because our relative perception of frequency is not constant across different levels.
  • Our judgement of frequency balance and loudness is not constant with time. This is particularly true if we tire our ears out with working – it becomes harder to make reasonable decisions.
  • To get the best out of our equipment, we need to understand how it works and interconnects; this means knowing about the various different dB scales we will encounter, and how they should align.
  • Recently, a number of areas have adopted a recent ITU recommendation on a loudness (rather than level) based form of metering and specification for broadcast. Other sectors are investigating following suit, so it is quite likely that this will be a standard and required practice.

Insofar as the ITU recommendation arose as an attempt to circumvent the sonic race to the bottom of the ‘loudness war’, this whole issue of how we relate the levels of our equipment, our perceptions of loudness and our working practices occurs at a complex intersection of technology, psychology, aesthetics, economics, politics, philosophy, etc…

Levels and dB

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