K System

The K-System is a protocol for setting mix and monitor calibrations in a studio environment. Introduced by mastering engineer Bob Katz in 1999, the system is an attempt to standardize leveling practices throughout the audio industry. It uses three separate standards known as K-20, K-14, and K-12. With each step (K-20, K-14, K-12 respectively), the available dynamic range decreases as the average level increases. This versatility allows the K-System to accommodate a wide range of audio material and mediums.

History

By 1999, Katz had become increasingly frustrated with the lack of leveling standards in the music industry. For the previous 25 years, Film mix engineers had adhered to the Dolby standard of -20dBFS=0 VU= 85dB SPL with fantastic results. The music industry however, had no such standard and discrepancies between average recording levels in commercial recordings were becoming apparent. Engineers had been choosing their own average record levels and adjusting their monitors accordingly. In other words, there was a lack of consistency in perceived loudness from one recording to the next. Volume knobs on commercial CD players were all over the place. Hoping to quell the building chaos, Katz introduced “an integrated system of metering and monitoring that will encourage more consistent leveling practices” (Katz).

Meters

In his proposal of the K-System, Katz lays a guideline for the type of meter to be used in conjunction with it. Katz asserts that the ideal meter for the K-System should be a linear-decibel scale using a combination of both VU and peak characteristics. The VU portion of the meter is used to monitor the average level of the recording, while the peak meter is used to prevent the given medium from overloading. In each and every case, no matter what meter is used, the 0 point on the scale must correspond to an average sound pressure level of 85dB on the monitor gain.

K-20

The K-20 or “Papa meter,” offers the widest available dynamic range of the three systems and should be used primarily for large theatrical mixes, dynamic music mixes, and Classical style mixes. Any material with a wide dynamic range should be reserved for the K-20 standard. In this system, -20dBFS = 0VU = 85db SPL. 20dB of headroom is available in the K-20 system.

K-14

The K-14 or “Mama meter,” should be the standard for the majority of commercial recordings created for home listening. Pop music and home theatre mixes are examples of material that would fall under K-14. In this system, -14dBFS = 0VU = 85dB SPL. 14dB of headroom is available in the K-14 system. The available dynamic range of K-14 is 6dB less than K-20. In other words, about 6dB of compression would be needed to convert a program mixed at K-20 to K-14. K-14 is likely to be the most widely used of the three standards.

K-12

The K-12 or “Baby meter,” is reserved exclusively for broadcast material, be it radio or television. With this system, -12dBFS = 0VU = 85dB SPL. A limited headroom of 12dB is available with the K-12 standard, which explains its exclusiveness to heavily compressed broadcast material. The available dynamic range in K-12 is 2dB less than K-14.

References

Katz, Robert A. Mastering Audio the Art and the Science. 2nd Ed. ed. Boston: Elsevier/Focal P, 2007.

Yewdall, David Lewis. Practical Art of Motion Picture Sound. 3rd Ed. ed. Burlington, MA: Focal P, 2007.