Getting the most from aux sends requires you to understand how they work!
The recent release of Pro Tools 2022.6 brought with it, among other things, improvements to Dolby Atmos re‑renders, enhanced MIDI workflows and the option to display or burn‑in timecode in video. Useful as these are, the development which will make the most difference to me is a new preference allowing you to set a custom default level for newly created aux sends. I discuss this feature later in the ‘Default Send Levels’ box, but this also seemed a good opportunity to discuss the way sends are handled in Pro Tools generally.
Sends & Sensibility
A track in Pro Tools has a fader which controls the level going to an output or a bus. It is possible to route the track to more than one destination, but with only a single fader to control the output level, it is not possible to do so at a different level for each destination. In other words, using the main fader alone allows you to send a single mix to one or more places, but to have two different mixes, you need two sets of faders. Creating an aux send gives you an additional fader with which to create a different mix.
Why would you want to do this? The two classic use cases are effects sends and monitor mixes. There are other reasons you might want to use sends, but these two neatly illustrate the difference between pre‑ and post‑fade sends.
Sends are useful for more than just headphone mixes and reverb.
In The Post
Exactly where the signal being sent via an aux is coming from makes a difference to how it behaves. A pre‑fade send is unaffected by moves on the main fader, making it independent of the main mix. Post‑fade sends, as the name implies, get their signal after the main fader, meaning that the level of the signal is controlled both by the main fader and that of the send.
This pre/post business can be confusing, and to make matters worse, both ‘pre’ and ‘post’ begin with ‘P’. Pro Tools sends are switchable between pre and post modes by hitting a button marked ‘P’ — not very helpful! In this case, it stands for Pre, and clicking the ‘P’ button so that it illuminates blue puts a send into pre‑fader mode. Screen 1 is a Photoshopped Pro Tools channel strip, in which I’ve rearranged the Headphones and Reverb sends to show them in their true position in the signal chain.
The reason these two varieties of aux send exist is to avoid unhelpful consequences. For example, if you want to share a common reverb across multiple tracks, the best way to do so is to use sends to route different amounts of each track to a bus feeding an Auxiliary Input track with a reverb inserted. However, if you were to use a pre‑fade aux send to do this, changes made to the main mix wouldn’t be reflected in the mix being sent to the reverb, resulting in the wet/dry mix of each channel changing as its main mix level gets changed. This can be avoided by using a post‑fade send.
Conversely, if musicians being recorded have specific requirements for what they hear in their headphones, a bespoke monitor mix can be set up using sends, but if you were to use post‑fade sends, changes made on the main faders would also affect the monitor mix, which your artists may not appreciate.
The way Pro Tools treats sends is very familiar to anyone who has used analogue consoles, though it’s no longer safe to assume that everyone has such experience. Sends are post‑insert, meaning that plug‑in processing affects the output of a send as well as the main fader output. Sends can feed busses or outputs, and up to 10 can be used on a track. If you can’t see the send slots in the Edit or Mix Views, go to the View menu and select Edit Window View or Mix Window View, and select A‑E or F‑J.
You create a send by clicking on an empty slot, and then selecting the output or bus you wish to route it to. Renaming is a good idea (‘Room Reverb’, ‘Slap Delay’) and can be done by right‑clicking the send slot (no need to visit the I/O window for this). It is possible to display sends as mini‑faders in an extended view in either the Mix window or in the track headers in the Edit window. This is done on a per‑slot basis by Command‑clicking (Control‑click on a PC) the arrow on the left side of the send slot. While it is possible to display all 10 sends slots in this extended view, it will use up a lot of screen space! Luckily, managing sends from the default view is well thought‑out.
Much like with inserts, Command‑clicking (Control on PC) defeats the send, in this case muting rather than bypassing. Control‑clicking (Windows‑clicking) mutes the send and all subsequent sends (this also works with inserts), and of course Option (Alt) and Option+Shift (Alt+Shift) can be added to extend this to all tracks or all selected tracks, respectively. Shift+Q will mute all sends in selected tracks, Shift+4 will mute sends A‑E, and Shift+5 will mute sends F‑J.
Floating Send Windows
The unexpanded ‘Send Assignment’ view features a tiny level meter (if you can’t see these mini‑meters, right‑click on a meter and select ‘Show send assignment level meter’ in the contextual menu). These meters are just big enough to show activity, but are a bit small for spotting potential clipping. Luckily there is a floating send window (Screen 2), which can be accessed by clicking on the Send Assignment. This presents a full‑sized fader, meter and other controls. A couple of these are worth a special mention. The FMP button switches the send into ‘Follow Main Pan’, and the Pre button toggles the send between the aforementioned pre‑ and post‑fader modes.
If you want to open multiple floating send windows, either click the red target button before opening new windows, or use Shift when clicking on the next send. Using multiple floating windows can be useful when managing monitor mixes during tracking, so if this something you do regularly, it is worth saving a Window Configuration as part of your template.
A lesser‑known aspect of these floating send windows is the role of the little white disclosure arrow at the bottom right. Click on this and you’ll reveal an extra meter. This is a meter which shows the summed level for the output or bus your send is feeding. The send meter only shows the signal being sent to that bus or output, but this second meter is the meter you would see if you were to create a Master Fader for that output or bus. This is a useful way to monitor headroom at that summing point if you don’t have a Master Fader for that bus or output in your session.
Because Pro Tools offers the option to set a different meter type for tracks and for Master Faders, you can set your Master Fader meter type to something better suited to monitoring headroom (Linear, for example), and you’ll find that meter type displayed in this second meter in the send window.
Other Uses For Sends
Sends are useful for more than just headphone mixes and reverb. Say you’re trying to apply sidechain compression to a track, ie. compressing one signal according to the level of another. This is most conveniently done using a send to feed the key input of a dynamics plug‑in.
You can also set a send to feed more than one destination. To do this hold Control (Start on a PC) and select an additional output/bus. A ‘+’ in the output field indicates a ‘mult’ output. This also works for the main output.
Setting up parallel compression for plug‑ins which don’t feature a Mix control can also be achieved using sends. Using a send for this task allows you to control exactly what’s hitting the compressor. And one of my favourite creative uses for sends is on effects returns (Screen 3). Get hands‑on with a control surface, and route a delay return back into itself for dub‑style experiments (maybe include a limiter, this is after all creating a feedback loop), or route between different effects returns for multi‑effects mayhem!
Default Send Levels
So back to the new preference I mentioned at the beginning of this article. Pre 2022.6, new sends were created either at ‑∞dB or at 0dB, depending on a setting in the Mixing tab of the Pro Tools Preferences. By definition ‑∞dB is always too quiet, and 0dB is usually too loud. The new preference (Screen 4) allows you to set a custom default for newly created sends. This is really useful as it will affect every session I work on. Nice!