Loudness war or presence war?

[neptunian]

http://en.wikipedia.org/wiki/K-system
Download Voxengo SPAN it has a K-meter included. Choose it and make sure that your loudest audio signal floats around the 0.

Thanks! Found another good article on the Bob Katz K-system: http://www.digido.com/level-practices-part-2-includes-the-k-system.html

So the K-20 mode should always be used for mixing. But which mode to use for mastering metal? According to the article,

If engineers find themselves using the red zone all the time, then either the monitor gain is not properly calibrated, the music is extremely unusual (e.g. "heavy metal"), or the engineer needs more monitor gain to correlate with his or her personal sensitivities.

Since metal is a "freak" genre, should one therefore use K-12 instead of the usual K-14?

 

[Skaldir]

So the K-20 mode should always be used for mixing. But which mode to use for mastering metal?

Use the K-brickwall
Personally I think there is no need for visual metering systems. Its ok to have a quick look if your current master isn't too odd, but mostly it isn't when it sounds alright.