[BC] Audio levels

[Peter]

On May 2, 2008, at 11:53 AM, Richard Fry wrote:

> Literally read from standard SI abbreviations, dBm just means  
> decibel-milli -- which is not a measure of anything.

But, dBm is a "word of art" and not an SI unit.

To those experienced in the art and science of broadcast and  
telephony, dBm has a well-understood meaning, the SI-unit committees  
in France be damned.

dBK isn't an SI unit, either. It is also a "word of art", and on  
account of its Form 301 usage is has a legal meaning, too.