Key Of Grey

August 12, 2010 – Have you ever seen the send fader (usually it’s a rotary pot) and wondered what it was for? Why send the signal somewhere else for effects? After all, in DAWs, you can insert an effect directly on the channel strip without having to send the signal elsewhere.

You can think of a send like running parallel processing. While inserting an effect directly on a channel strip sends the signal in a linear flow (audio > effect > out), the send allows the signal to be sent to two places at the same time. You might have your channel routing the audio to a stereo bus, and also send the same audio to an auxiliary channel simultaneously. On that auxiliary channel, you may any number of effects. By using a send, your audio will be output twice.

Ok, now that we know that a send acts like a splitter, why would you want that? The simple answer is that it gives us more options. I’m sure you’ve seen tutorials on parallel processing on instruments like drums or bass. It involves copying the track twice, and putting different effects on each, with a blended final product. Using a send, you can achieve the same effect.

If this all sounds overly complicated, it’s really not. Here’s a common way to use sends that will allow you to save a lot of processing power and help you glue your mix together. Create an auxiliary channel that feeds your master. Right now there’s nothing going into the track, but there will be. Insert an EQ on the auxiliary channel and roll off the low end. Insert a reverb unit after the EQ. Choose a setting that emulates a room with a lot of space.

Next, solo the auxiliary channel and start turning up the sends from all your tracks. It’s like you’re creating a really reverb-y and treble-y mix. Now un-solo the auxiliary channel and listen to the overall mix. What you’ll notice is that everything starts to sound more natural; like the instruments are playing in the same room. By sending a little of every track to the auxiliary, it glued the mix together (this is only one of many ways to make a mix blend well) when it was all combined. Consider how this is different from adding a reverb unit on every instrument separately and attempting to mix the separately reverbed tracks together.

The big advantage of using sends in the manner above, is that you can get the snap and impact of the original track (which can be separately effected), combined with the washy sound of the reverb. Normally when you insert an effect, you don’t get this option (unless your plugin has a wet/dry setting). Back in high school when I was mixing on super old 4-track tape reels and a very basic mixer, if I sent a guitar to a reverb unit, I got reverb or nothing. With sends, you can have your cake and eat it too.

The first time I tried Logic on a Mac, when Powerbooks were still around, I immediately suffered from a core audio overload when it couldn’t handle the multiple reverb units I was greedily adding. I quickly learned that putting one Space Designer plugin on an auxiliary channel got me the sound I was looking for, at a significant processing power savings.

So here are the top reasons for using auxiliary sends:

3. Save processing power.

2. You can glue a mix together by combining the sends from multiple tracks to one auxiliary.

1. You get to put effects on the same audio in two different ways, and then can mix them independently of each other.