We often hear about mixing but not about the tools involved behind it. Constituting an essential part in any music production setup, the audio mixer is one of the most important elements involved in the polishing of a sound. It can be virtual or physical and referred to by as many names as a mixer, a desk, a board, a soundboard or an audio production console. However, mastering an audio mixer will be a necessary step if you want to succeed in audio production. If the tool in itself is complex, you should think of a mixing console as a way to centrally control audio and process various musical components. A good analogy would be the dashboard of your car which controls at the same time your A/C, radio, lights and additional controls.
In this article, we will focus on explaining the main parts of a mixing console, its most relevant sections, whilst giving you our insight on the usage of mixing consoles. The end of this article will be dedicated on giving you a few tips in the craft related to audio mixers, mixing.
VIDEO : “Mixing Consoles Explained (Part 1)”
What is a channel strip ? Why is it the mixing console’s essential part ?
The most important element of audio mixers is the channel strip. This processing center contains most mixer functions. All consoles have faders that allow for volume control, pan knobs to position a sound from left to right, an auxiliary section to control effects, headphones or monitors and very specific functions. Most console channel strips, real or virtual, will include the following functions:
2. +48 V – Provides phantom power required by most condenser microphones.
4. Line/mic – Determines if the channel will be used with a mic (send) or as a line (return/monitor).
5. Phase flip – Flips the polarity 180 degrees on the channel selected. This is a great feature to use when checking phase between stereo mics.
6. EQ section – Varies from console to console and with the type of software being used. It can change the tone of the signal that is being routed through the channel.
7. Auxes/auxiliary – Used for monitoring and effects (FX). With live sound, they control the mix sent to the stage monitors. In the recording studio, auxes are used to build a headphone mix. When the aux is used for monitoring you will typically select “pre.” Both in the studio and with live sound, auxes are used to apply FX to a particular channel. When the auxes are used for FX you will typically select “post.” This ensures that the FX isn’t heard unless the fader is up.
8. Pre & Post – Allows the user to select whether Aux sends are before or after the fader. In “pre,” the aux path would be before the fader, meaning the fader would not affect what is being processed. As previously mentioned, “pre” position is typical when the aux is being used for headphones or monitors. When you turn a fader up or down it will not affect the headphone mix. In “post,” the auxiliary knob would be after the fader, meaning the fader position would affect the aux send. The “post” position is used when the aux is being used for FX.
9. Monitor section – Another option to return the signal from the recorder to monitor the sound. This section is typically used during tracking and can also be referred to as the tape return section or as Mix B.
10. Pan – Allows you to place a sound anywhere between the left and right speakers.
11. Fader – Controls level being sent to a bus or a recorder.
12. Bus(es) – A common path that allows the engineer to combine signals from as many channels as you select. A bus on a console is typically configured for 4-, 8-, or 24-channel mono or stereo L/R. Often the Bus section is shared with the Group or Subgroup section.
13. Solo – Allows you to isolate the channel selected from the others. However, multiple channels can be soloed at the same time.
14. Mute – Turns off sound on the selected channel; opposite of solo.
VIDEO : “Mixing Consoles Explained (Part 2)”
What are the (most) relevant sections of audio mixer ?
The preamp controls the gain and is used to boost a microphone signal. The preamp section usually has a +48 V button to apply phantom power to the required mics. The line button is often found in the preamp section. When the line button is pressed down, it receives signal and acts as a tape return. Although many consoles don’t say it, when the line button is up, mic is selected. So really the line button is either line or mic depending on your selection.
2. EQ Section
The EQ section gives control over the tone or color of the instrument being run through the selected channel. This allows the user to boost or cut a frequency or range of frequencies. The most common parameters associated with an equalizer are frequency, amplitude, and slope (Q). EQ sections are divided into specific frequency bands. Many consoles will be broken up into three bands with a low-frequency knob, a midfrequency knob, and a high-frequency knob. Some consoles will have a fixed set of frequencies to choose from, while other consoles give control to select virtually any frequency between 20 Hz and 20 kHz.
Next to each frequency knob will be another knob, or pot, to adjust the amplitude of the frequency you have chosen. There will be a center point on the amplitude knob, where nothing will be boosted or cut. Adjusting the knob to the right of this point will increase the amplitude of the frequency selected. Adjusting the knob to the left of this point will decrease the amplitude.
3. Auxiliary Section
Auxes are used to control FX sends (reverbs, effects). They are also used to control headphone and monitor mixes. In the studio, auxes are used to create a headphone mix or are used as FX sends. For live sound, auxes are used to create a stage or monitor mix and to control FX. The “pre” button located near the aux send, when selected, puts the aux path before the fader. The pre is selected when the aux is being used as a headphone or monitor send. By this way, the engineer can have their own fader mix and the adjustments won’t affect the headphone mix. The pre will not be selected when you want to use the aux as an FX send.
4. Monitor level and faders
The fader would typically be your monitor level, but when recording it controls the amount of signal going to your recorder. A fader controls the volume of a channel. It is almost always found at the bottom of the console, and to some, it appears as a “slider”. Faders can act as returns to monitor signal or as sends to control output to a recorder.
5. The Bus section
The bus section can be found near the fader at the bottom of the console or at the top of the console near the preamp. Most consoles have eight busses, but some have up to 24 busses. The bus allows you to assign the channel to a variety of signal paths and is commonly referred to as “routing matrix”.
6. The Master section
The master section will have the master controls for the faders, auxiliaries, speakers, and other inputs and outputs, like an external two-track or CD player. The master fader is where all individual sounds are summed to two channels: left and right. The master auxiliary section controls the overall volume of the auxiliary selected. Most consoles have both an Aux Send master section and an Aux Return Master section.
VIDEO : “Guide To Mixing – The Master Section”
7. Meters (Peak, VU & RMS meters)
Meters on a console indicate the amount of signal input or output from the channel, stereo bus, groups, or auxiliary section. Meters come in many forms, with the most common being a variety of peak and VU meters. VU stands for volume units and this type of meter responds much more slowly than a typical peak meter used with digital audio. A peak meter responds quickly and is essential with digital audio because recording levels in the digital world cannot exceed 0 dBFS. Unlike a VU meter that measures the average amount of voltage, a peak meter measures the peaks. Conversely, RMS meters display the average loudness of a channel or the stereo bus, indicating the dynamic range of the signal when compared to the zero point. Meters are not just found on consoles, they are also found in audio software programs and on most pieces of analog and digital outboard gear.
VIDEO : “Mixing Consoles Explained (Part 3)”
8. Where, why and when are audio mixers used ?
Mixing consoles are used in recording, live sound, or in conjunction with digital audio workstations (DAWs). Moreover, audio mixers are used in the context of mixing, where a music producer has the difficult task of blending and editing different tracks (audio, software instruments) to create a harmonious result which will be pleasing to the listener. As mentioned before, in the all-digital world, there are virtual mixers. In the real world, there are control surfaces that allow you to work on hardware instead of clicking a mouse when using a DAW.
9. How to use an audio mixer in 8 easy steps
- Connect the audio equipment to the mixer’s inputs.
- Connect the recording or monitoring equipment to the mixer outputs.
- Turn on the channel inputs that will be used to make the sound mix.
- Turn on phantom power for the channel if the item connected to it requires it.
- Adjust the volume for each input as required.
- Adjust the treble, bass and mid-range bands of each channel with the equalizer controls.
- Route those channels needing special effects to an auxiliary channel.
- Pan each channel in the master mix as required.
VIDEO : “How to Use an Audio Mixer Board Tutorial Mixing”
10. How can I master an audio mixer ?
Practice and dedication will be your biggest assets here. Mixing, as any other process in music requires the full understanding of the different processes and components which are involved. Moreover, it is only by repeatedly using your audio mixer to blend and edit tracks together that you will make massive improvements. Whether you are working on a physical or a virtual console, many of the mixer controls are the same. If there are 32 channels on the board, understanding the controls on one channel is a huge step because understanding one channel means you will understand all the 32 channels. Once you learn one channel strip, you will know quite a bit about the console or virtual mixer. At a certain point, you will naturally know which sounds go well together and which ones shouldn’t be associated.
VIDEO : “The difference between Good Mixing and Great Mixing”
11. Some basic mixing tips and techniques
- When you mix, you should avoid using the solo function. Make sure that your music sounds great as a whole, rather than individually. Sometimes, during the creative process you come up with individual sounds that you weren’t really planning to produce, but they end up giving a nice addition to your mix. The main pitfall when relying on solo is that you won’t perceive your sound in relationship with other sounds.
- A rule that is given by many music producers and professionals in the field is that you should always trust your ears no matter what. When mixing, it is easy to get caught up with all the lights, knobs and parameters. But, think about it, meters won’t tell you much about how you perceive a sound and if you like it. Often, when it sounds good, it is good. Meters should only be there to tell you if you are operating your equipment at acceptable levels. Of course, this doesn’t mean that you should allow your mix to clip.
- Music producers rely on different sources to verify how their mix translates. Some may use headphones, others may use speakers. However, you should always makes sure that your mix sounds good on a lower quality of speakers. If this is the case, chances are high that it will sound good on most systems. Studios typically have at least two sets of speakers that the engineer will use to A/B (compare) sounds. Consider having at least two sets of speakers that specialize in different areas.
- Another trick is to check your mix in mono. When you do this, you make sure that they are in phase and that they will be translating well on a mono system (i.e: clubs).
- Finally, always remember that the three essential steps of the mixing process are the following:
1. Visualization: Picture how you want the mix and the individual instruments to sound. Instead of aimlessly turning the EQ knob trying to find a frequency range that sounds good, visualize how you want the sound to end up. Fatter? Brighter? Edgier? You can then turn the knobs with a purpose.
2. Application: This involves fader adjustments, panning, signal processing, equalization, and applying FX to the mix.
3. Evaluation: Evaluate the changes you just made. Were you able to achieve your vision with the action taken? Evaluate what is working and what isn’t and continue this three-step process until everything is tweaked the way you like.
Recommended additional resources on the mixing topic:
Being a central and essential tool of any music production setup, the power of the audio mixer should not be underestimated. The pre amp, EQ, bus, master sections and meters constitute the essential functions and elements of a mixer. It is only by learning them thoroughly and understand all their settings that you can deliver an accurate and representative mix. Setting up a mixer and repeatedly practicing and experimenting with its parameters will give you a natural way to approach mixing.
Finally, we really hope that the basic mixing tips and techniques we mentioned will give you a good head start in the process of mixing. If you want to learn more about the process of mixing, we would recommend you to check out our article on the basics of mixing.
- Dittmar, T. (2011), “Audio engineering 101”