From: Marcos de Lacerda Navaes
Mr. Katz:
You’ve mentioned adding black or roomtones in between tracks. Could you explain why and what are these tones and what levels should be applied (dB’s)?
Marcos: Digital black is “complete silence”. You should be able to verify this with a professional level meter, or a video monitor or an oscilloscope.
Many editing programs are able to supply silence with ease. Room tone represents the “sound of the room” in which the recording was made. A professional editor has to make these kinds of decisions based on the kind of musical material and whether it will benefit from having black between tracks or room tone.
There is no right answer as to when to choose room tone or silence. This must be made by careful listening.
For example, a recording made from analog tape will have a small amount of hiss on it. It is often very disconcerting to replace the hiss between the tracks with absolute black; often the transition to “black or silence” sounds worse than the noise that was there in the first place. The same thing often occurs when you replace room tone (the sound of the room, the recording electronics, etc.) with silence. This is an artistic judgment that should be made by an experienced editing person.
This person may also choose to slowly segue (crossfade) between the end of the cut and a lower (3 dB less perhaps) level of room tone. This transition is smoother than going to silence, and gives the impression of a quieter tape, but still does not have absolute silence on it between the tracks.
Presently I’m dealingwith a digital source that leaves an almost inaudible pop when”going black”, and keeping up with the signal a few dB’s in between tracks maybe the only solution to avoid it. Any further comment you may have will be much appreciated.
Have a nice day!
Marcos.
Your pop is probably due to DC offset in the source, which was encoded in the original.
You can get rid of the pop by using a crossfade between the source and black, or by using a DC removal filter when you output to CD or by cross fading to room tone in between tracks.
To put in a plug, I can help you out of this problem here at Digital Domain if you can’t fix it there.
Hope this helps,
Best regards,
Bob