Using the FX Send on Live Mixers - Reverb

A lot of live mixers, including many of the smaller ones, have an FX send with digitally built in effects. A lot of these FX are quite obsolete and useless in my opinion, they can be very overpowering. One effect however stands out above them all: reverb. An effect that is commonly heard in almost every song, it adds a huge amount of difference to a vocalist when applied. I am going to use the context of small acoustic gigs for this, as these are my main source of direct experience.

So, you have a few guitars, and maybe a couple of singers playing live. They are sounding good, but how can we improve it? Well, by using the FX sends, we can actually do quite a lot.

Bear in mind, many mixers only let you apply one effect at a time, so we are going to use a simple reverb. My example mixer is going to be the Soundcraft EFX 8, an 8 channel mixer, with an FX channel.

1. Setting Up and Understanding the FX Channel

So how do we add FX? Look at the image below, the purple knobs, (encircled in red) are the sends. These allow a portion of the channel to be split off and sent to the effects channel (encircled in green).

Imagine that you have several rivers (each channel), they will all feed into a pond (the master channel). The sends, are like diverting small portions of the rivers through a processor (the FX channel) before sending them into the pond. Let's say this water processor added a dye, depending how much water was sent through it, and depending how much it let into the pond, the resulting colour of the pond could be either faintly coloured or very strongly dyed.

So how can we improve a live mix with these FX? Well, we know vocals often sound amazing with a fair amount of reverb on them, so let's turn the sends of the vocal channels up. Twelve o'clock will do for now. 

This will essentially send some of the track into the channel with the purple fader. Make sure to select a reverb setting on the FX channel for it to add reverb.

A quick MS Paint diagram showing the route the audio takes regarding
an FX send on a mixer. The purple and red lines denote a hotter
signal being sent e.g. for the vocals.

If the purple fader is all the way down, no reverb will be heard. If it is all the way up, the reverb will be mixed in quite loud. When setting up the sound, I have the FX fader set around eight-tenths of the way up and adjust the sends of the vocals to get a nice sound mixed in with the Dry (unaffected) signal. 

By having the fader below max, it allows you to boost the amount of reverb for choruses and long notes temporarily without having to alter the FX sends.
So, let's continue with the analogy of two guitars and two vocals, we probably want a small amount of reverb on the guitars too. I usually send the guitars at a much lower level, perhaps start with the guitars' send knob turned to nine o'clock. 

This means that even if the FX fader is all the way up, the vocals will have more reverb (relatively) applied to them.

2. In Use

So, now we have the reverb set up. Let's look a bit more into how we can use it to make it sound good. As the music is playing, you may want to alter the reverb depending on the part of the song. 

As a general rule, for live sets with only a few channels, e.g. the acoustic gigs described above, I use reverb to fill out the sound. 

Small sets like the one pictured above often need some reverb to fill
out some of the space. (Band pictured: Bella and the Bear, an incredible 
band from Scotland who I was lucky enough to do the sound for one of their
first gigs)

Remember how I told you to set the FX fader at eight-tenths of the way up? This is a good level to have as default as it allows you enough room to boost the reverb when needed, but never allows you to go overboard with it. 

During the quieter parts of the song, where the guitars are soft and the vocals are prominent, it can often feel quite empty. This is a good place to bring the reverb up a bit. It will fill the spectrum with a bit more sound, as well as expanding the "space" which they are singing in.

Conversely, and almost paradoxically, you also want to add reverb for the louder choruses. This will further increase the power of the vocals and guitars and make the sound a lot more full. 

So where would you bring the reverb back down? Well, I tend to do it for the verses of the songs where you want a bit more vocal clarity, if you ride the FX fader right, you can bring it down just before the chorus and sort of "slam" it when the chorus kicks in, this adds a greater effect and contrast.

All these differences that I'm describing are actually needing to be quite subtle, I do not mean go from fridge sized room to cavernous reverb. These changes should only be noticeable if they are listened out for. The job of the sound-guy/lady is to make the artist sound like they are sounding great all by themselves. The best jobs you can do, are the jobs where your work isn't even noticed.

It looks bad on the band if you are frantically adjusting everything 
use sound-checks to get everything sounding fine before the act starts!

So my mixing technique for live bands like this is have one hand on the channel faders, and one riding the reverb. Since small bands only really use four/five channels, you can manage their levels with one hand, freeing the other for the FX fader, that same hand can also be free to tweak EQs and small FX send changes.

Play about in sound-check and always ask the artists what the want.