Music Mastering Trends In Loudness of tracks By JDM
During the late fifties, early sixties and onwards it was common practice that 7” singles were mastered, recorded and released “loud” The maximum peak level of analog recordings such as these, is limited by varying specifications of electronic equipment along the chain from engineering, the source to listener, including vinyl record and cassette tape players.
Introduction of the Compact Disc
With the advent of the Compact Disc (CD), music is encoded to a digital format with a clearly defined maximum peak amplitude. Once the maximum amplitude of a CD is reached, the loudness still can be increased even further using signal processing techniques like dynamic range compression and equalization etc.
we can apply an increasingly high ratio of compression to a recording until it more frequently peaks at the maximum amplitude. In certain cases, clipping and other audible distortion is introduced to increase loudness even further.
Extreme dynamic range compression tecniques
Recordings that use These extreme dynamic range compression techniques and other measures to increase loudness therefore sacrifice sound quality to loudness. Again the point is that a compromise has to be acheived to get the acceptable loudness of the wanted audio.
The principles of the mastering technique to produce a loud track can be traced right back from when 7″ singles were first introduced and were played in jukeboxes of which most had a fixed audio level. The concept was that the louder the track would be would attract the attention of the audience. There were certainly limitations of how loud analogue vinyl could be mastered but because of the digital era and computerised technics that can be implemented, we can have a greater controll over the loudness of a track.
The common practice of mastering music involves matching the highest peak of a recording at, or very near to, digital full scale, and referring to digital levels very much like analog VU meters. Usually, −14 dB below the disc’s maximum amplitude would be used in the same way as the saturation point that would be signified as 0 dB of analog recording, with several dB of the tracks recording level reserved for amplitude exceeding the saturation point, referred to as the “red zone”, where we see a red bar in the meter, because digital media cannot exceed 0 decibels relative to full scale (dBFS). The average level of the average rock song during most of the 80s was around −18 dBFS
During the 90s louder music levels were even more popular, resulting in recordings, where the peaks on an average rock or beat-heavy pop CD hovered near 0 dB but just very occasionally reached this level.
Interestingly in 2008 Metallica’s cd album “Death Magnetic” , has a high average loudness that pushes peaks beyond the point of digital clipping, causing distortion, taking the trend a step further This was and has been open to critatsm that people prefer to hear the full dynamics at a normal loudness level. It seems that now with music trends towards downloads rather than compact disk, that there may be a possibility that loudness levels could be capped. Already some cloud based services have implemented loudnes level normalization. Weather you approve or dissaprove of these trends it seems that like everything in this world the decision will probably, eventually be made for us.