Channel Strips: Understanding Your Virtual Console
Before diving headlong into your first mix on Logic Pro, it’s worth taking some time to distinguish among the various channel strips that the Mixer is comprised of and how these various elements interact with each other. Generally, a good mix in Logic Pro makes use of all the features of the Mixer – channel inserts, bus sends to aux channel strips, output masters, and so on – so it’s worth familiarizing yourself with their features in much the same way as an engineer would “get to know” the sections of a physical console.
Audio Channel Strip
An audio channel, as we’ve already seen in the previous chapters, governs the basic path in and out of Logic Pro for a recorded signal. In a mix, audio regions in the corresponding track will be sent down the channel strip, through the various insert processors (compression and EQ, for example) and bus sends (for reverb and other eff ects) to a designated output.
Instrument Channel Strip
The instrument channel strip duplicates the same features as an audio channel strip; only this time you get to work with the signals generated by the virtual instruments in your session. In addition to this simple application, an instrument channel strip can also be configured for multichannel operation so that multiple outputs from the same instrument (like the EXS24 or Ultrabeat) are sent to a number of additional auxiliary output channels. Besides having individual level control, this also allows you to apply different effects onto each output so that a snare, for example, might have different equalization, compression, and reverb to that of a kick drum.
Aux Channel Strip
The humble aux channel strip is one of the most useful parts of Logic Pro’s Mixer and the source of a number of different techniques in mixing. First, it can be used as means of applying send effects like reverb or delay – anything where you want to actively control the balance of wet and dry sound using a separate fader. In this example, the aux channel strip has the effect strapped across its insert path with instrument channel strips or audio channel strips sending signals via designated bus sends. This allows any number of channels to access the same reverb, for example (an essential way of preserving DSP resources), as well as being able to control the return of the effect in the same way as any other audio signal in the mix – in other words, it could be equalized, compressed, and controlled by movements of the fader.
Another less immediate, but altogether just as useful, technique is to use an aux channel strip to combine a number of different channels (including audio and instrument channels) on a single fader. For example, many engineers using a traditional console will create a submix of the drums to a selected bus master fader (in this case, one of Logic’s aux channel strips), allowing them to quickly control the level of the drums relative to other instruments in the mix. Additionally, they could also make use of inserts on the bus faders to apply compression, EQ, and so on, to the entirety of the drums, rather than individual channels within it – something which can just as easily be done of Logic’s aux channel strips.
The final important role of the aux channel strip is to operate as a means of inputting external signals into the mix. If your audio interface supports enough inputs, there’s no reason why you can’t patch-in external compressors, equalizers, synthesizers, and so on, directly into your mix. Although you might need to account for a small amount of latency (as discussed in Chapter 3 ), using dedicated recording hardware can often supply much more character than conventional plug-ins. Of course, given the provision of inserts on these aux inputs, there’s no reason why you can’t also use Logic plug-ins on top of whatever device you’re inputting into that particular aux input.
Stereo Output Channel Strip
The stereo output channel strip represents each of the physical outputs in your Logic system. If you’re using a simple two-in, two-out USB audio interface, you’ll only see one of these faders. However, if you’re working with a multiple output FireWire or PCIe soundcard, you can increase the number of output faders corresponding to each physical output. On the whole, most mixes simply use one designated output (1–2) as the “destination” of the two-track mix. If you intend to render the mix directly from the Logic session, you’ll also need to make use of Bounce “Bnce” button, found on the output channel strip or File > Bounce (for more information on bouncing to disk, see Chapter 9 ).
MIDI Channel Strips
Arguably, MIDI channel strips should be kept distinct and separate from the audio mixing, but given their inclusion as part of the Mixer, it’s worth clarifying their exact role. Unlike all the other Mixer channels in Logic (which control the flow and qualities of audio within the application), the MIDI channel strips have no direct control of the “internal” properties of your mix, but instead they work as controllers for external MIDI hardware connected to your MIDI interface. However, in the case of the synths and sampler being returned via aux channel strip, these MIDI channel strips could have a direct eff ect on your audio mix – maybe balancing 16 MIDI channels being returned to one stereo input on your audio interface.
Master Channel Strip
The master channel strip provides a quick-and-easy access point to the level of signal going to all main outputs and is directly linked to the “volume” control as part of the features on Logic Pro’s transport bar. In situations without control room monitor levels, for example, this could be used as a means of adjusting the monitoring level, although it should be noted that any digital bounces made in Logic will be subject to the master channel strip’s gain adjustments.
Note that you cannot insert plug-ins across the master fader in stereo mixing (instead use the Stereo Out strip), with the master channel simply being used as a level attenuator. In surround mixing, however, its role – and the role of the outputs – slightly changes, which we’ll cover in more detail in Chapter 10 .
Excerpt from Logic Pro X: Audio and Music Production by Mark Cousins and Russ Hepworth-Sawyer © 2014 Taylor & Francis Group. All Rights Reserved.