Originally Posted by digital desire
Watching SNL now.
Why is it that the audio level is so different between the show and commercials?
It is really bad, especially the furniture commercials, and the dunkin doughnuts (John Goodmans voice) which are almost blow out inducing!
Is that willful do you suppose, or just "happens"?
You didn't mention it, but I assume you were watching the HD channel. The audio level during NBC HD segments is entirely under NBC control. It travels a pretty short path from the satellite receiver, through a switch (the other input of the switch is locally originated audio), into the Dolby encoder and right on out to Time Warner and the digital transmitter. Altogether it is probably 15 feet of wire, all digital. We don't bring it down to analog, and don't use any auto-level devices on the NBC HD audio.
NBC also provides metadata (it comes out a serial port of the satellite receiver, and plugs in to the Dolby encoder) which controls the channel configuration (for instance, 5.1 vs. 2.0) and audio level. Lately, a lot of NBC HD is 5.1 (many prime time shows, Today, Tonight, Late Night, SNL), which puts most of the dialog in the center channel.
Local audio is handled much differently. It is always 2.0, the front L and R only. That alone tends to make it louder during local segments (two speakers instead of one). Plus, the device we use to even out the local audio levels broke a few weeks ago. That means if a tape operator dubs a commercial into the video server with somewhat high levels, they are going to be somewhat high on-air. We just received replacement parts to fix the audio level controller, so if all goes well, I'll have that working again sometime on Monday the 23rd. It still won't be a perfect match between NBC HD and local audio, but it should be much better.
It is interesting to watch the levels on NBC HD material. During a program when people are just talking, with no music and no sound effects, there is virtually no activity on L, R, rear or sub. Only the center channel has audio, and it usually peaks at no more than -30dB. If they suddenly have loud music and big crashing sound effects, all the other channels can suddenly light up with much higher levels. Audio techs constantly debate how to deal with audio levels in the digital, multi-channel world, and there are various recommendations on what the average levels should be for various types of programming.
I guess my point is that NBC HD levels will vary a lot, and our average level for locally originated audio won't necessarily match what NBC is doing at the moment - although, as I said before, you should notice an improvement by Oct 23rd.