Every working system must have standards. Standards are tested examples of behavior, measurements or conditions which allow for an expected result. For example in a hospital environment it is a standard recommended by the CDC for patient care staff to wash their hands before and after patient handling. This reduces the spread of infections and other subsequent factors. Also in film, there are a number of standards. Dolby originally proposed a standard loudness measurement of 85dBSPL at 0VU in the 1970s. It was a unit of measure that allowed dialogue, music and special effects to fall in nicely with audio soundstage of the film. This standard has stood the test of time and is still utilized today.
However, this is not the case for popular music in media. There are no loudness standards in the record business. Which makes the result unexpected for the audio listener. This is one of the reasons the iTunes and iPods are equipped with the "Sound Check" feature. In the 1990s music and media production professionals began to notice the average loudness of CDs increasing at a rapid rate. The use of powerful compressors and limiters enabled mixing and mastering engineers to produce music with an average metering level that was the same as the peak level, typically called "brick wall limiting".
Some believe this was the result of digital recording, which has a much larger signal-to-noise ratio than analog tape recordings. I believe it is a combination of many factors but perhaps the most consequential was the abandonment of the VU meter. The VU meter was an averaging meter and allowed a mixing or mastering engineer to view the overall loudness of a recording with some accuracy. In the digital age we have traded in the VU meter for Peak metering.This shows us the highest point which signal can reach before distortion. And keeping music just under 0dBFS and extremely compressed has become the target for many music producers and engineers alike. In the days of the VU meter the peg and LED would alert the anyone watching far before the digital Peak meters read-off.
The Solution to the Loudness Race
Today, lack of a metering standard in the record business has allowed the audio soundstage of popular music to become boring and monotonous. And the loudness race has developed into a bonafide problem for music listeners, whether they know it or not. Bob Katz of Digital Domain has proposed an integrated approach to metering, monitoring and leveling practices that makes sense. It is called the K-System.
The K-System was developed with the idea that, "the medium is not the message". Therefore, when monitoringwe are considering the musical content and artist expression of the music to determine its overall loudness and not just insensitively crunching numbers to get the loudest result possible. And like the film industry, the K-System is tied to a calibrated monitor gain where the averaging meter's 0 equals 85 dBSPL. And while the metering system does show a linear-decibel reading, with peak values, it has dual characteristics where the VU level is the dominant part of the display.
More can be learned about this system in Mastering Audio: the art and the science 2nd ed.
Hakim Callier (@hakimcallier) is a music producer and audio engineer in Harlem, NY. He is the eldest son of Rick Callier, music producer and arranger for DeBarge, Fred Hammond & Marvin Sapp. Hakim graduated from the Institute of Audio research and studied Information Systems at New York University. He is currently working on music for media productions and freelance engineering sessions. You may contact him at (646) 377-3926 or info@hakimcallier.com
September 23, 2009