Today our Musistic University recording tutorial by our audio engineer Curtis covers the topic of submixing in Pro Tools.
Problems can arise when all of your audio tracks are sent to the master fader. They can be tamed through various submixing techniques. Routing various tracks through busses and into auxiliary inputs before the master fader can provide greater control over mixing the audio, and also opens the door for multiple alternative mixes and mastering chains.
A basic submix can be done by creating an aux input with the output set to the same output as the master fader and with the input set to the stereo bus path of your choice (I have my Bus 1-2 automatically named “MIXBUS” for this reason.) Route all of your audio-outputting tracks to the input specified on your sub-mix aux input track. This routes all of your audio into a single track before you send it to the Master Fader and allows for more control and signal chain options.
Alternate sub-mixes can be created using sends. Using internal busses and the sends section of the tracks, send the desired audio-outputting tracks to another aux input track. You can then use the send faders and pan controls to create mixes of the tracks to the alternate sub-mix input. Be sure to set the sends to “Pre-fader” so that your changes to the track fader won’t affect the mix sent to the alternate sub-mix aux input. With your tracks routed to an alternate sub-mix channel you can try out different mixes or mastering output chains in a non-destructive way. The output of the alternate sub-mix can be set to the master output for easy mute/unmute functionality to listen to different sub-mixes. The output of the alternate sub-mix tracks can also be sent out of an audio interface output in order to create personalized headphone/monitor mixes for performers. Multiple alternative sub-mixes can be created alongside each other. To have easy access to these controls, try placing the sends to a specific submix on the same send letter, and then showing expanded send controls in the mix window by selecting “View > Expanded Sends > Send Letter.” This places send level, pan, mute, and pre-post fader controls for all sends of that letter into the mix window for easy access.
When mixing using a sub-mix technique, soloing an audio track can lead to silence unless you also solo the desired sub-mix aux input channel. This can be tedious, especially when your audio source is going through multiple aux input tracks. Pro Tools provides a simple way around this known as Solo Safe, which doesn’t mute a track’s output whenever another track is soloed. You can Solo Safe your aux input tracks by Command + Clicking (Mac) or Ctrl + Clicking (WIndows) the Solo button of the track that you want to Solo Safe. Enabling a Solo Safe will allow you to listen to a soloed audio outputting track without soloing all of the aux inputs along its signal path.
Alternate submixes can be achieved by sending all of the desired tracks through a specific bus that is assigned to a single aux input channel. The level and pan controls on the sends can be used to create multiple alternate sub-mixed of your project. Be sure that Pre-Fader Listen is enabled so that your changes on the track’s controls don’t affect your sub-mixes. The alternate sub-mix tracks can also be sent out of additional outputs on your interface to be used as headphone or monitor mixes for performers.
Most of this information is from the September 2014 issue of Sound on Sound magazine page 154.