[This article was first published in the January, 2009, issue of
Larry's Final Cut Pro Newsletter. Click here to subscribe.]

I got my start in radio, many years ago. This taught me my love of audio. And I have always enjoyed talking with audio engineers about their craft and technology.

But one thing I've learned is that if I get five audio engineers in the same room at the same time, I'll get seven opinions on what constitute the best audio levels.

Proper audio levels really do vary - a lot.

Still, there are some general guidelines which I want to share with you here, that can keep you out of trouble and your projects sounding great.

Note: Please consider these as guidelines. If you are given specific technical specs from someone who actually knows what they are talking about, then please follow the specs. Otherwise, where no specs exist, my guidelines can keep you out of trouble.

CHECKERBOARD YOUR AUDIO

First, when building your audio in the Timeline, consider checker-boarding it. This means to put all the same audio on the same track.

There are several benefits to checker-boarding:

• Having a consistent organizational structure for editing your audio decreases mistakes and speeds editing.
• It makes it easier to figure out what you did when you go back to re-edit a project you haven't worked on for a while.
• It decreases the amount of time an audio engineer needs to reorganize your project if you send it out for mixing, which saves you money
• It is a common-sense, professional way of working.

Audio engineers have been checkerboarding their projects for years. In fact, my system is modeled after many that I've seen used in professional audio suites -- where mixing a major motion picture soundtrack can have over 100 tracks of audio!

While I don't expect you to be mixing an audio project that big, we can still follow the same procedures.

So, here is how I organize the audio in all my projects:

A1, A2: Main talking head audio - for example, the main speaker on V1
A3, A4: B-roll audio from clips on V2
A5: Narrator
A6, A7, A8: Sound effects - wild, not synced with video
A9, A10: Music cue 1
A11, A12: Music cue 2

If I don't have a narrator, or don't need three sound effects tracks, I simply move everything up. But I ALWAYS build my sequences in this order.

If I have a guy narrator and a girl narrator, I'll put them on separate tracks, as they get different EQ and filters during mixing.

NEVER GO OVER ZERO

The most important rule to remember with audio is that your audio MUST NOT EVER go over zero. Not once. Not even a little bit. Not even when no one is looking. NEVER!

Unlike analog audio, digital audio starts distorting as soon as your audio levels exceed zero and those red clip lights flash on. While you are mixing, these red lights tell you that your audio levels need adjusting.

However, during final output, those red lights indicate that your audio has been permanently damaged and there is not a technology on the planet that can fix it. You'll need to go back to your source materials and remix.

SETTING THE RIGHT LEVELS

Audio levels are additive. This means that as you add more audio clips at any given point of your Timeline, your audio levels increase. Four clips of audio playing at the same time are louder than any one of them playing alone.

However, since we add clips one at a time during our edit, it is useful to rough in the audio levels so that you can get a sense of how things are going to sound.

Remember, do not allow a single clip, or the audio as a whole, to ever exceed 0 dB.

With that as background, here are my recommendations on setting levels. This assumes you are using Final Cut Studio or Soundtrack Pro (or ProTools, for that matter).

Since the sum of all audio can not exceed 0 dB, have your meters bounce between -3 to -6 dB for the total mix.

To achieve that, here is where I rough-in my audio during editing:

Talking head audio: -6 to -12 dB -- this is the SOT, or Sound-On-Tape)
Sound effects: -12 to -18 dB -- this is the NATSOT, or Natural-Sound-On-Tape)
Music underscore: -18 dB

Then, I use my good ears, my good speakers, and my good common sense to make things sound right - given that the sum of all my audio levels fall in the range of -3 to -6 dB.

I've found that these levels sound great when used for DVDs, web video, and general purpose broadcast.

Note: Many broadcast commercials are mixed to a level of -10 dB, with no dynamic range. Again, if you are given specifications for your mix, please follow them.

THOUGHTS ON OTHER AUDIO MEASURING SYSTEMS

You sometimes see references to dBFS. This refers to how audio levels are measured. Final Cut uses a dBFS scale. However, that is not the only way we have to measure audio levels... that would be too easy.

In the UK, they use an entirely different audio measuring system called PPM. There's a very useful Final Cut utility called PPMulator+ that displays PPM levels inside Final Cut projects. Generally, PPM levels between 3 and 4 are considered appropriate.

In Europe, they use dBU.

Older, analog systems use VU (Volume Unit) measurements.

As I was researching this article, I got a very helpful email from Woody Woodhall, of Allied Post Audio in Santa Monica, and head of the Los Angeles Post-Production Group. Woody writes:

These systems are all measuring the same thing. What's confusing is the dBU and dBFS. The dBU looks to me to be modeled after analog metering which goes into the "+" range and dBFS is absolute and stops at zero. The formula to convert from one to the other is:

0 dBU = 4 PPM = -18 dBFS = -4 VU

[Depending upon project] levels for broadcast delivery are:

+8 dB = 6 PPM = -10 dBFS = +4VU

Like video editing, audio mixing is both art and science. But it need not be a mystery. Using these settings can help your projects sound great -- while keeping you on safe ground technically.

UPDATE - Jan. 7, 2009

Bob Merrill adds:

I wanted to add one thing regarding audio levels. If you are using Compressor to make MPEG-2's for your DVD's, make sure and set the "Dialog Normalization" to minus 31. Failing to do so will result in a final audio level lower than expected.

Larry replies: Thanks, I've mentioned this before in other training, but am happy to add it here.

UPDATE - Jan. 7, 2009

Woody Woodhall sent me an illustration of the mess we've made of audio levels. He writes:

If [you are creating a project] for broadcast my experience is that the "peak" levels delivery specs are either all over the place or non-existent. In December I delivered a commercial to [a large] cable [system], I asked for their audio specs. They sent me a very nice sheet that had a lot of information regarding the video and a sentence that said "Program Left should be Channel 1 and Program Right should be Channel 2."

I then called, found a master control operator who told me to "do whatever you usually do." So much for standards...

Larry replies: Thanks. I've also gotten a couple of emails expressing confusion over being told to set program levels at -20 dBFS. Because audio is logarithmic, setting program levels this low means that you are using less than 12.5% of your total audio dynamic range. This makes no sense to me! However, I'm doing some more research and will supplement this report if I find anything that needs revision.

Larry Jordan is a post-production consultant and an Apple-Certified Trainer in Digital Media with over 25 years experience as producer, director and editor with network, local and corporate credits. Based in Los Angeles, he's a member of both the Directors Guild of America and the Producers Guild of America.

The information in this article is believed to be accurate at the time of publication. However, the author assumes no liability in case things go wrong. Please use your best judgment in applying these suggestions.

The opinions expressed in this article are solely those of the author. This newsletter has not been reviewed or sanctioned by Apple or any other third party. All trademarks are the property of their respective owners and are mentioned here for editorial purposes only.

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