Mixing Sound and Keeping the Levels Equal

[Dave Haynie]

You can’t balance things that aren’t similar enough. A good example is shooting a musical performance — you may have clips of music, clips of speakers, etc… they’re going to be at drastically different volume levels.

You probably want to compress speech, but you definitely don’t want to just randomly apply compression to music. The former is generally informational, the latter… is music. It’s supposed to be dynamic.

Even if I’m just using a mic or two, I will ALWAYS split up different kinds of audio into different tracks. So in a typical musical performance, I’ll have an voice track and at least left and right music tracks, even if I’m just using a single set of mics. I always want to be able to mix the voice to the center channel, if there’s the option of a 5.1 audio output… and I’ll think in those terms, anyway. That’ll be a mono voice mix… and I’m talking about things like announcements in-between music sections.

It should be obvious that with other kinds of speech, like dramatic speech, theater, etc. you don’t want much if any compress, and you’re going to keep the stereo mix. You’d be dealing with speakers who are using their vocal modulation for an intended effect, not just those who might not be careful about their vocal levels when making announcements (or whatever). And of course, if a normalized speech track sounds clean, you may not want the compression — it’s just fairly typical that light to moderate compression is a good treatment for speech.

Normalization is also necessary, or at least very useful. I would typically do RMS normalization of voice at around -10dB and music at around -16dB, but it going to depend a bit on the content. Using RMS normalization (not built-in to Vegas, but available in Sound Forge) means you’re not having your normalization thrown off by the odd noise or other unusual sound. So -10dB always sounds like -10dB.

You can get into trouble with compression either pre or post normalization, if you don’t know what you’re doing. Most of the plug-ins use compression curves that assume you’ve already normalized the content, and most automatically provide some make-up gain, so the output will have about the same levels as the input. If you’re not well versed in applying compression, it’ll be easier to normalize then compress. Knowing what I’m doing relative to these, I usually do it the other way around.

-Dave

[Debbie King]

Hi Lance:

I know this thread is so long ago. Would you be able to tell me how to get the -6db on Wave Hammer Sound? There is no selection, only the levels for output, threshold and ratio. Which one should I level at -6db?

Many thanks.

Best,

Debbie

[Mike Kujbida]

Debbie, here are two screenshots of the way I think you want to set up Wave Hammer. On the recommendation of an audio engineer friend of mine, I always bypass the Compressor on that tab.