Fundamentals of a Mixing Console – The Master Control For An Audio System
Jul 13, 2022I remember the very first time I stepped up to a large format analog mixing console. It was in Chicago at a music venue called the Metro, and the console was a Midas Heritage 3000.
And like all analog desks that can accommodate 48 channels, it had a TON of knobs, buttons, and faders. Totally intimidating! But analog all have similar layouts, so getting my hands on it and running a show ended up being fairly manageable.
Nowadays, the most difficult thing is not the number of knobs but using a digital console that you don’t have experience with. Unlike analog, these are all laid out differently and have proprietary software. Totally intimidating!
However, even though digital consoles are all different, they use the same fundamental concepts and signal flow that analog consoles do. So, if you have a solid understanding of audio terminology and signal flow, you’ll be able to walk up to any console, analog OR digital, and get a mix going.
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My “day job” is touring around the world with bands mixing FOH sound. I love doing it and it definitely satisfies my travel bug! And even though I’ve been lucky enough to do some big tours mixing Grammy-nominated and – winning artists, I also see the exact same audio practices and techniques used in churches, theaters, and anywhere live music is being played.
Overhead view of a basic audio mixing console. Click to make full size.
But, unfortunately, there’s been a severe lack of training with live sound, which is why I started The Production Academy. We provide pro-level live sound training online. And one of the free courses I put together is an 8-video series about the fundamentals of a mixing console – I’ll provide a link at the end of this post.
So, if you want to learn more about how to use a mixer, you should definitely come check out the videos. But for now, let’s discuss the overall signal flow of a mixer, which has 2 main components: Inputs, which are the channel strips for the mics and DIs on stage; and Outputs, which send our mixes to the speaker system.
1 – Inputs
Closeup of a single audio channel strip. Click to make full size.
When capturing the sound of the musicians on stage, we use microphones and DIs to get the sound into the console, each of which is connected to its own channel strip. And even if you’re on a digital console, the signal flow is the same as an analog console.
Basically, the channel strip is made up of 4 sections: Preamp, EQ, Pan/Mute, and Fader. Each of these provides ways to boost, shape, and route the audio signal.
The Preamp adds Gain to the signal, which boosts the mic-level signal to line-level. Setting the Gain correctly is one of the most important things you can do in live sound, because it affects everything else in the signal chain.
The EQ lets us shape the tone of a signal. This is a really powerful tool that gives the sound engineer a ton of control over the sound of any instrument – it’s one of the main creative decisions we make when building a mix.
The Pan/Mute section has a few important features. We can control where the instrument sits in the stereo field, and we can also mute it. But we also find the Solo/PFL button here, which lets us hear the signal in headphones, and also helps us set the Gain correctly.
The Fader is a great tool because we can easily grab it and adjust the level of the instrument in the speakers. And apart from just adjusting level, this is also where you assign the signal to the output that you want it to go to.
2 – Outputs
Inputs being routed to the main mix and subgroups. Click to make full size.
Once we have all the input signals sounding good, we mix them together and send them to the outputs. This is how we feed FX, monitors, and the main speakers. And there are 3 types of outputs we see on most mixers: Aux Sends, Subgroups, and Main Mix.
Aux Sends are a really useful tool that are used mostly for monitors and FX. They can be set to Pro or Post, which affects where in the signal chain they are picked off. Aux Pre can be used for monitors so the channel Fader won’t affect the Aux sends. And Aux Post is typically used for FX, which means it’s affected by the EQ and fader settings.
Subgroups are additional outputs that are used in various ways. They can be set up as a separate control for groups of instruments, like all the drum channels or all the vocal channels. Then, they can get sent to the main mix and on to the speakers. Or, they can be sent directly out of the console to feed something like a recording device.
The Main Mix is how we feed the main speaker system so the audience can hear the music. This is usually two discrete outputs so we can have separate left and right signals and create a stereo mix. We also use an EQ on the main mix to compensate for things like a boomy room or a harsh sounding speaker system.
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I hope this helps with understanding the overall signal flow of a mixing console. Of course, this is a very brief overview and there are many more things to discuss with how to use a mixer! You can always come see our FREE 8-video series at www.TheProductionAcademy.com. Just CLICK HERE to come check it out!
Happy mixing,
Scott Adamson
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