by Craig Anderton
There are four main ways to add effects with digital audio workstation recording software. The most common method is to add software plug-ins as series insert effects—the track’s audio goes through the effect, then into the DAW’s mixer. Some DAWs also let you use spare audio interface I/O to route a track through external hardware effects.
There are also master effects, which affect all buses and all tracks for an entire mix. However, one of the most useful options is adding effects to a send (or auxiliary) bus as this lets multiple tracks feed a single effect, and simplifies techniques like parallel processing.
HOW SEND EFFECTS WORK
Audio tracks use send controls to “pick off” some of the track’s audio and send it to a bus. An effect inserted in that bus processes any audio it receives. The classic send effect application is reverb, where different tracks send different amounts of audio to the send reverb effect—for example, if you want lots of reverb on voice and guitar but not bass, you’d turn up the voice and guitar track send controls that feed the reverb bus, while leaving the bass’s send control down. The send bus output re-enters the DAW’s mixer via a “return” channel or track (Fig. 1).
Figure 1: This Ableton Live project has two returns for send effects—Delay and Reverb. The Guitar, Vocal, and Drums tracks all send some signal to the Reverb, but only the Guitar track sends audio to the Delay. The Delay bus is selected to show its two send effects: A Line 6 POD Farm stereo delay, preceded by EQ that reduces low and high frequencies in order to accent the delay’s midrange.
Sends typically can be pre- or post-fader. With post-fader selected, reducing the track’s main fader simultaneously reduces the send level. With pre-fader, only the send level control determines the send level, independently of the track fader’s setting. Furthermore, Mute and Solo buttons typically affect a send only if it’s post-fader.
KEEP IT WET
When using send effects that have a wet/dry balance controls (like reverb or delay), remember that this effect is in parallel with the track feeding it. As the original track is feeding the DAW’s mixer with a dry signal, you’ll usually set the send effect for wet sound only, then use the return track’s level control to balance the amount of wet signal with the original track’s dry signal.
Another trick involves changing phase. If you reverse the phase (polarity) feeding the send bus, this will tend to cancel out any residual dry signal in the send bus effect. For example if you’re using a phaser as a send effect, there’s still some dry signal in there even if the phaser’s wet/dry control is set to all wet. Canceling out some of the remaining dry signal produces a kind of “super-phaser” effect.
SENDS AND SIDECHAINS
Sidechaining with software plug-ins also makes good use of sends, because a track send usually provides the track’s signal to a sidechainable device. Typically, the sidechain input will show up as an available send destination (Fig. 2).
Fig. 2: In Cakewalk Sonar, a send from the drums feeds a control signal to an Expander/Gate processor inserted in the bass track. There’s also a Compressor on the bass track; this is being gated by the Damage drums in Kontakt.
Note that for sidechaining, you’ll almost always want the sidechain set for pre-fader, so that the amount of signal feeding the sidechain is constant. This also lets you solo the sound of the track with the sidechained effect without muting the track that provides the sidechain signal.
Also remember that when sidechaining via a send bus, you can insert additional effects to process the control signal. For example with a dance mix, you might want to filter out everything but the snare so you can “pimp” a compressor on another track whenever the snare hits.
SENDS AND PARALLEL EFFECTS
Those are enough ideas to get you started, but be creative and you’ll surely come up with some more. And if you do, feel free to add a comment and tell the world about it!
Craig Anderton is Editor Emeritus of Harmony Central. He has played on, mixed, or produced over 20 major label releases (as well as mastered over a hundred tracks for various musicians), and written over a thousand articles for magazines like Guitar Player, Keyboard, Sound on Sound (UK), and Sound + Recording (Germany). He has also lectured on technology and the arts in 38 states, 10 countries, and three languages.