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Automated Mixing (part 3)

Mute automation: This is the simplest component of mix automation, but it’s a very powerful tool...


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Mute automation

This is the simplest component of mix automation, but it’s a very powerful tool. There are a number of mixing consoles available which provide mute automation but not automation of fader levels. Mute automation is also sometimes available as an add-on box which can be fitted to any console. It’s a while since I last saw units of this type advertised, but they are potentially so useful I’m sure they will make a comeback. Mute automation is simply a way of turning channels on and off during the mix. You will use this to clean up the individual tracks so that each track is only unmuted when it has something useful to contribute to the mix. When the track contains nothing of any musical value then it only contains noise, and even if that is only the quiet hiss of noise-reduced analogue tape, then when a number of tracks are mixed together the noise produced will indeed be noticeable. With mute automation it is possible to conceal noise very effectively, and also get rid of any unwanted noises that found their way onto the tape during the recording process. For example, it is common to have a singer who breaths too loudly, and the sound of the breaths comes too close to the actual singing to erase them from the multitrack. Mute automation can deal with such breaths easily, although don’t be too enthusiastic or it will sound that your singer performed the whole song without breathing at all! You may say that you can achieve the same thing with noise gates, and cut out unwanted noise this way. You can, and with the added advantage that you can tailor the attack and decay to the signal you are processing. But you will find that a channel of muting is much cheaper than a channel of gating, and also since you will instruct the system yourself when to mute and unmute, you will never get any false triggering, which is the scourge of good gating.

The next question is, how does the system know when to mute and unmute? The answer is that it will synchronise with timecode. If the console has its own internal muting system, then it is the console that must synchronise. Or in some cases the muting will be controlled by a conventional MIDI sequencer via note on and off messages, so it is the sequencer that must synchronise to the tape. The standard method of synchronisation these days is to stripe the tape with SMPTE/EBU timecode, and convert that on playback into MIDI timecode (MTC). All your mutes and unmutes will be logged against MTC and play back at exactly the right times. There are two ways of entering mute data. One is on a channel by channel basis, probably using MIDI note on and off messages. The other is via ‘scenes’ or ‘snapshots’, probably activated by MIDI program changes. You will develop your own favourite way of working, but there is probably more flexibility in the channel by channel approach. Something you will come across very quickly in your automated muting career is the need to extend or shorten mutes. Suppose you have programmed the system to unmute the vocal channel for a particular line of the song, just before the first note starts. Then the producer asks you to release the mute a second earlier to capture the singer’s intake of breath. This is just one case of extending a mute, and here the unmute time must be made a little earlier. The full set of possibilities are these:

  • Mute on earlier
  • Mute on later
  • Mute off earlier
  • Mute off later
  • Mute on and off both earlier
  • Mute on and off both later
  • Mute on earlier and mute off later
  • Mute on later and mute off earlier

I don’t think I’ve missed anything out. The way the automation system handles mutes for you may make life easier for you, or more difficult. If you only have one mute button per channel it will toggle the mute on and off, and you will probably be in a permanent state of confusion since when you are trying to adjust a mute both you and the computer will be pushing the button! Check this point out when you look at an automation system. I’ve just been looking at the Uptown Automation system, which I have to say is not the cheapest around, and I loved the provision of separate mute on and mute off buttons. It made shortening or extending mutes a doddle.

By David Mellor Thursday January 1, 2004