In which situations are measuring and/or correcting
loudness needed? Due to the establishment of numerous international
broadcast standards, broadcasting is the obvious answer - and even
within a broadcast context, loudness measuring is relevant at many
different points of distribution.
However, the loudness issue is not only relevant to broadcasters, but also to production, post and mastering engineers. In the following, we will go through the various loudness application scenarios.
Broadcasting: Transmission (metering)
Obviously, it is important to keep an eye on loudness during transmission.
Broadcasting: Transmission (correction)
Monitoring loudness is not always enough, as the transmitted audio may need to be corrected. In this case, a loudness processor that complies with the broadcast standard that the station uses is the solution.
Pre Broadcasting: Ingest & Quality Control
The process of transferring and storing data to servers prior to transmission is called ingest, and here it is also recommended to monitor the loudness and, if needed, adjust level offsets to match the target level of the broadcast standard the station uses.
Post Broadcasting: Logging
Loudness meters that are capable of creating a log file of the program material being measured is valuable for post transmission evaluation and consumer quality control.
Production, Post & Mastering
It may be wise to monitor loudness in all steps of audio
production, all the way from early production and recording stages
to post production and mastering. Program material that has been
mixed and mastered using traditional sample-peak normalization as
well as large amounts of compression to appear as loud as possible
may in fact turn out to be perceived as being softer than average
if the station transmitting the program material complies with a
broadcast standard and adjusts accordingly.
Further, a log file of the loudness accordingly to a standard may also be appropriate to deliver to the next step in production to prove compliance with one or more standards.