This is where it all happens. Everything you want coming out of your sound system has to come in, be processed and directed out to FOH (front of house) speakers, monitors on stage or in ear, and recordings.
My supplier lists over two hundred mixers. Starting around three hundred dollars, including powered mixers, these really are bargains for what you get. You can narrow the choices down quickly with these questions:
How Many Inputs?
This is not the same as number of channels. Most boards call one stereo input two channels. Make sure you have enough mic/line inputs and can use the other types of inputs offered. Vocals, instruments, can your speakers handle bass and drums? Always get at least two or more extra channels. You shouldn’t be swapping any mixer connection in middle of a show. Having extra inputs allows setting up and sound checking everything before you start.
How Many Monitor Mixes?
(a.k.a. PREFADER SENDS) Separate mixes increase the threshold of feedback (a good thing). Several small monitors can run at lower levels when each vocalist can be loudest in their own mix. Not everyone wants keyboards in their monitor, so a separate mix with keys and their vocal eliminates need for a keyboard amp. Less stuff on stage and to carry.
(a.k.a. POSTFADER SENDS) Many mixers today have onboard effects that are great. Having extra post sends and/or insertion points to connect outboard effects offers additional flexibility. Don’t forget extra inputs for effect returns.
Sub masters allow you to group like inputs into a separate volume control. If your mixer has them, you can control all vocals or all drums with one fader. If you’re using over twelve channels and have a sound person, it’s a nice addition. Sound from stage, just something else to be miss set.
The louder you want to play, the more EQ you need. Equalization on inputs is more about blocking unwanted sounds from your mix. On outputs, it’s about matching speakers FOH (front of house) and monitors to the room. Adding a kick drum mic requires at least a three-band mic input EQ. This allows you to turn middle frequencies way down, blocking all the sounds that get picked up by the drum. An output EQ lets you turn down the resonate frequencies in the room from a loud kick drum.
Stereo or Mono?
Mono is all you need. Rarely is your whole audience able to hear both speakers. But separate left and right controls allow easy volume control of both sides of FOH. This shouldn’t a be deciding factor, other options are more important.
Analog or Digital?
Analog mixers are much simpler to learn and use. Even though the effects built in are digital, all the controls are easy to see and understand. Digital mixers have it all, full parametric EQ (everything adjustable), gate, compressor, limiter, even feedback suppressors. But you, and hopefully another member of band, should know all pages of software and available settings. One obscure setting can shut the whole thing down.
Buy newer or better quality for your main mixer. Only a few people carry or even have a second mixer available if it fails. In the old days good, sound engineers kept diagrams of mixer settings and output EQ for the venues they played. Once your mixer is set up and sounding good, take a picture, save settings on digital devices, include USB stick copy. Your mixer should solve problems not create them.