The K-System: Standards for Sound

What is the K-System? The K-System is a proposed standards system of metering and monitoring for audio to preserve the dynamic range of the audio. The K-System was proposed by mastering engineer Bob Katz in his paper An Integrated Approach to Metering, Monitoring, and Leveling Practices.

The K-System is primarily an integrated calibration system. The calibration handles the relationship between three primary components; the Master Meter within the digital audio workstation, or DAW, the VU meter, and the calibration microphone. This relationship can influence the overall dynamic range available to the audio and create uniform monitoring with optimal listening conditions.

The first part of the relationship is the Master Meter within the DAW. This master meter has a maximum limit of 0dB Full Scale. This denotes the highest capacity of the digital audio system. Any higher than 0dBFS, and digital distortion is the result. Sound is made up of peaks, which are sharp instances of audio, and RMS level, which is overall level. The trick here is to apply compression selectively to keep audio peaks from breaching this barrier but bringing the RMS level up to the level prescribed by the K-System.

The next part of the relationship is the VU Meter. The VU Meter measures the analog voltage created by the audio. This is a measure of the decibels RMS, which is a measure of the perceived loudness. The VU Meter is a monitor of the overall level.

The last part of the relationship is the calibration microphone. This measures actual sound pressure level or dBSPL. According to the Fletcher-Munson Curves, the optimal level for monitoring is 85dBSPL. This level creates the flattest frequency response for the human ear. Therefore it is imperative that this part of the relationship remain fixed at 85dBSPL.

So where does the K-System come in? The K-System can be broken down into three separate calibrations; the K-12 for dynamically uniform music, K-14 for dynamically complex music, and K-24 for film. Each of these creates increasing dynamic range based on the intended audio and destination. Film requires much more dynamic range as opposed to electronic dance music, therefore different calibrations are chosen.

The calibration works thusly. For this example we are working within the K-14 system. We set the RMS level of the Master Meter to -14dbFS, which we then set to equal 0dBVu, which then equals 85dBSPL. This creates uniform standards which create ideal dynamic range for the audio and also ideal listening conditions for the mastering engineer.

In summation, the K-System is an easily integrated system that creates standards by which the quality of audio can be improved. These standards allow better product for the consumer, and an easier creation process. Integrating this system at all stages can create a streamlined process for later engineers and improved organization for yourself.