Multi-channel Audio Output Tricks

[ This article was first published in the January, 2004, issue of
Larry’s Final Cut Pro Newsletter. Click here to subscribe.
Updated June 12 & 18, 2004
with info on the Device Control window and Downmix button. ]

All versions of Final Cut only support two-channel audio input. However, new with FCP 4 is multi-channel output.

While we CAN’T send an audio track to more than one output channel at the same time, we CAN send any audio track to any output channel. And we can create any even number of audio output channels — from two to 24.

Keep in mind, however, that DV output only supports two channels. So, you’ll need extra hardware, like an AJA I/O box or Black Magic card, to get more than two audio channels out.

I recently got to test this with a project requiring 4-channel audio output to a DigiBeta deck, and I discovered there are several different settings that need to be changed:

1. Sequence settings (Command – zero)
2. Audio Outputs for each Audio Track
3. AV Device Control settings
4. Downmix setting on the Audio Mixer

Sequence Settings

Here’s the process. First, set the number of audio output channels:

• For EXISTING sequences, go to:
  Sequence -> Sequence Settings -> Audio Output tab

 

• For FUTURE sequences, (in other words, to make this a standard setup for your FCP system) go to:
  Final Cut Pro -> Audio/Video Settings -> Sequence settings -> Audio output tab

 

 

• From the pop-up menu, select the number of audio outputs you need (in this example, we’ll use eight). Note that outputs appear in pairs.

 

 

• Then, set each output pair to either Stereo (the default) or Dual Mono, then close the dialog box.Stereo automatically pans the odd numbered channel to the left and the even number channel to the right. Dual mono pans both tracks center. If there is NO relationship between the audio on the channels, use Dual Mono. Otherwise, Stereo is great. Leave the level settings at zero for Stereo or -3 for Dual Mono.

 

Assign Each Track to an Audio Output

• Now, to assign an audio track to a particular output channel, go back to your current timeline and CONTROL-click in the small space between the patch panel and the padlock.

 

 

• In the pop-up menu, select “Audio Outputs” and drag over to the channel(s) you want to assign your audio track. In the screen shot above, we are mapping track one to output one and two. Notice that stereo pairs are listed together (i.e. 1 & 2 and 5 & 6), while dual mono channels are listed separately (i.e. 3, 4, 5 and 6).

 

 

• In this example, we are assigning audio track 3 to audio output seven, which is a dual mono track.

Configure Your Device Control Settings

Hidden deep within the A/V Settings preference window is the last setting you need to make. And this one took me a while to find.

 

 

Go to: Final Cut Pro > Audio/Video Preferences > Device Control Presets.

 

Select the preset for the deck or camera you are using.

 

If you are using a DV device, the “Audio Mapping” option will be grayed out.

 

However, if you are using a multi-track device, and you’ve made the rest of the settings in this article, the Audio Mapping option will be active.

 

Select the number of channels you want to output, in the case of the DigiBeta I mentioned at the beginning of this article I set it to four, and you are ready to go.

Make Sure the Downmix Button is Off

When you are editing, your multiple channels of audio are normally “down-mixed” to two channels so you can hear them through your speakers.

 

When it is time to output, though, you need to turn this downmix setting off, otherwise, all your channels will output to two channels.

 

 

To do this, open the audio mixer and click the Downmix button so it does NOT glow dark gray. When you play your sequence, watch the audio mixer output channels to verify that all channels are outputting.

Summary

The advantage to this output flexibility is that you can reorganize your audio tracks as necessary, or feed multiple tracks to the same device, without having to do multiple passes through your sequence.

 

For example, this works well when you need to do a multiple output to video tape or DA-88, or if you want to control track mapping for audio export to ProTools through OMF.

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