Intensity of a continuous tone used for test purposes (measured in decibels by comparison with the standard reference level, or zero level, of 0775 volt rms, which is equivalent to a power of 1 milliwatt in a resistance of 600 ohms); colloquially, intensity of program output or of noise.
"I am delighted to have these old 78's from my childhood now preserved in listenable form on a modern sound medium. I would not have thought it possible to do that at such an affordable price! Thanks too for the "preservation" copies. I am very satisfied with your work, and I am especially impressed with the promptness of your service. "