Layout of a Mixer

What is the first thing that comes to mind when looking at a 24 channel mixer?

If you are like me, then you may be a little overwhelmed trying to decode the layout of all the knobs, buttons, and faders.

NO NEED TO FEAR! We are here to give you an in-depth guide so that you will be the expert and guide your church to make the perfect buying decision when looking for a new mixer. PLUS, you will be able to identify ways to optimize your existing system by the end of this guide!


What is a channel strip?

When looking at a mixer it is important to look at it as a set of columns or what audio engineers call the channel strip. Try Each channel strip is numbered and generally has the same exact controls. So, to make it easier, we will explain what is typically found on a mixer channel strip.

Here are a few controls a channel strip is composed of:

We will give a much more in-depth breakdown of a mixer’s controls later in this post, to give a basic understanding before we go in-depth!

Channel strip basic components:

  1. Preamp/Gain section
  2. Input section
  3. EQ/Auxiliary Knobs
  4. Channel Volume/Routing Controls

This vertical strip of controls is duplicated across the mixer. So as you are looking at the mixer try to think about it as a verticle column with the same set of controls duplicated over and over again rather than random knobs.

Each set of controls in a channel strip are in a specific order, this is what is referred to as a signal flow. The signal flow of these controls is ordered specifically to give the engineer the most control over what has been plugged into the mixer channel or what engineers refer to as the input signal.

In the image below you can see the signal starts at the person speaking into the mic. Then the singer’s voice goes through the microphone cable, through the mic input on the mixer, then the sound travels through the various components of the mixer, and finally out of the speaker. As this is a brief explanation, we think it is worth breaking down this topic in detail.

Signal Flow from start to finish (see graphic below):

  1. Singer
  2. Mic
  3. Microphone cable
  4. Mixer input section
  5. Gain/Preamp (what set’s the microphone sensitivity)
  6. Equalization section
  7. Auxiliary/FX section
  8. Panning
  9. Channel Volume/Routing
  10. Mixer main fader (overall volume control of all mixer inputs)
  11. Main outputs of the mixer
  12. Cable that connects mixer to the speakers
  13. Speaker input
  14. Speaker volume control

These components make up the signal flow from the point where the sound is coming into the system to the point when it comes out of the speaker. It is critical to understand these components so that if there are any malfunctions, the engineer will be able to quickly identify any problems by troubleshooting through the signal flow.

 

signal_flow.png

-Signal Flow Example-


Channel Strip Layout of a Mixer:

Let’s break down what a mixer channel strip consists of. We are going to go into even further detail of these individual components later in this post.

1- XLR Input (microphone input)

2- ¼ Input (instrument input)

3- Insert (to connect external audio equipment)

4- Gain (mic sensitivity knob)

5- Low Cut (removes unwanted frequencies)

6- -20db Pad (to reduce the input volume of the sound source)

7- EQ (to add or remove frequencies)

8- Auxiliary (used to send volume of the individual channel to a set of speakers)

9- Effects (to add echo or other effects to the individual channel)

10- Pan (to move the audio source to the left or right speaker)

11- Mute (to turn off the audio coming from the individual channel)

12- Volume Fader or Knob (to control the volume of the individual channel)

13- PFL Button (to be able to visually see the individual sound source volume on the mixers meter)

14- Main Output Routing Button (to send the audio from the individual channel to the main output)

15- Sub Groups eg: 1-2 (to send the audio from the individual channel to an output other than the main output)

signal_flow

-Mixer Layout-


Looking to purchase a mixer?

Cut to the chase and see our TOP RATED MIXERS FOR 2018!

We make sure to relate each recommendation to specific needs. We want you to make the right choice for you and your venue. See our 2018 mixer guide by clicking the link:

TOP RATED MIXERS FOR 2018


1- Microphone Input

Most mixers have a 3 pin female microphone input located either at the top of the channel strip or on the back of the mixer.  These 3 pin female inputs are meant for an XLR cable or more commonly referred to as a mic cable.  As combination inputs have become much more popular, instead of a mic input there is often a combination jack.  An XLR cable is still used with a combination jack.  If you look close you can see the 3 circular holes that are meant for an XLR cable.  The combination jack also accepts a ¼ inch cable.  Next, we will look at the next input on a mixer.


2- ¼ Inch Input

After the microphone input, we see that there is a ¼ input that is next on the channel.  Make sure to read below the ¼ inch input and that it reads “INPUT”.  If it says insert then your mixer may be using a combination jack or your mixer does not have a ¼ input.  Now, if your mixer has a ¼ input then you can use these inputs for anything that uses a ¼ inch cable.  Guitars, pianos, mics, etc…  There are several different instruments and sound sources that can use a ¼ cable, even cell phones can use an ⅛” to ¼” cable to play music (refer to the cable chapter for more information).

quarter_inputs


3- Insert

The insert on a mixer enables an engineer to add an external piece of equipment to a specific channel. Though insert looks like a regular 1/4″ input, it is actually both an input and an output. Think of an insert like a sound loop.

With a special Y shaped cable, the insert slot sends sound from a mixer channel then into an external piece of audio equipment and then out of the external piece of gear and back into the same mixer channel. 

TRS Y cable

The insert slot adds the external audio equipment in line with the signal flow of the channel so that the audio that is processed by the external gear can still be equalized by the mixer’s controls.

mixer_insert.png

The cable used for the insert on a mixer is referred to as a Y cable because it has 3 male 1/4″ ends and each has different functions:

TRS Y cable

A) TRS – This end of the Y cable is a TRS plug and takes audio from the mixer and sends it to the end of the Y cables labeled TIP but also receives sound from the other end of the cable labeled RING.

B) TIP – This end is 1/4″, MONO, and labeled TIP. The TIP end of the Y cable sends sound and meant to be plugged into an external piece of audio equipment so that the audio can be processed. 

C) RING – This end is 1/4″, MONO, and labeled RING. The RING end of the Y cable receives audio from the external audio equipment. The RING plug is plugged into the output slot of the external piece of audio gear.

The insert section is important when connecting vocal processors, compressors, and gates.  


Need to optimize your system?

Cut to the chase with our top 5 mixer essentials guide

If you have a great mixer and great speakers but your audio system still does not sound exactly how you would like it to, we have just the answer!

3 Outboard Gear Essentials for Audio Engineers


4- Gain

The word gain controls the sensitivity of the input channel and not to be used as a volume control.

The gain knob on a mixer is controlling a preamp, a preamp is able to raise very low volume sources to an audible volume that can be heard through a speaker system.  

For instance, if a mic is plugged into a mixer channel without a “preamp” but the mixer did have a volume knob down at the bottom of the channel.  Even if the volume was turned all the way up, no matter how loud someone screamed into the mic, the mic would not be audible through the speakers.

Overall, the gain knob is a preamp and it controls the sensitivity and initial volume of the anything plugged into the mixer channel.  

A volume knob then controls the overall audio of the channel coming through the speakers.  So, the gain knob essentially sets the sensitivity of the channel so that the volume knob can control how the audio from the channel fits into the overall mix coming through the speaker.

Using a gain knob like a volume knob will increase the potential of feedback.

channel


5- High Pass Filter

The high pass filter button is signified by a number like 80 or 100 and is accompanied by a symbol like the image below. Low cut and high pass mean the same thing.  High pass means that the low frequencies are cut, in other words, if the high pass filter says 80hz then it is cutting out 80hz and allowing all the frequencies after 80hz to be heard through the system.  

Vocals for instance, do not go as low as 80hz, so it would make sense to use the high pass filter on any channels that a mic is plugged into.highpass


6- 20db Pad

A pad is simply meant to lower the incoming volume of something that is plugged into a mixer.  There are times when a drum mic, for instance, will sound distorted no matter how low the gain is set. The next step is to press the -20db button.  This will lower the incoming volume by 20db and will clean up the distorted signal and create headroom.  

Headroom is the amount of volume available before the source begins to sound distorted.

pad


7- EQ

EQ Stands for equalizer!  

An EQ is generally made up of three different frequency groups called bands.

  1. A three band eq uses 3 groups, highs, mids, and low-end frequencies that pertain to specific frequencies in the human hearing range.
    1. lows (Bass 120HZ)
    2. mids (Mid-range frequencies 2500HZ)
    3. highs (Treble 8000HZ) 

eq.png

To better explain, the human hearing range is roughly 20 hertz all the way to 20,000 hertz.

  1. Lows are going to be in the 20HZ to 400HZ range
  2. Mids will be in the 400HZ to 1500HZ
  3. Highs from 1500HZ to 20kHZ.  

Generally, the highs and lows on a 3 band eq will be set to one specific frequency and the knob will be labeled like the image above.

DB means decibel, which is the way we measurement volume. If the knob for highs is labeled 2khz and the knob is moved to the left the volume of 2,000hz will be lowered. 

The shape of an eq curve is bell-shaped. So, even though an eq knob specifies a frequency, a few other surrounding frequencies are effected by the change. 

Now we will explain how the mid-range frequency eq knobs are laid out.  This eq is generally configured a little differently. 

  1. Parametric EQ – is made up of 2 knobs
    1. Frequency Knob – has the ability to select from a range of frequencies
    2. Volume Knob – able to add or subtract volume to the desired frequency
    3. These two knobs should have a line drawn illustrating that the two knobs are connected

A parametric eq allows you to sweep through different frequencies to zone in on a frequency causing problems.  A good exercise is to set the gain of the mids section to the right about a quarter of the way and then twist the frequency knob slowly to find and remove any problematic frequencies by listening for an increase in feedback while sweeping.   


8- Auxiliary

There are often at least two auxiliary knobs on an 8 channel mixer.  These auxiliary knobs can control the volume that is sent to a speaker on stage.  

Each channel on a mixer has its own auxiliary send so that each channels audio can be sent to the same auxiliary or monitor speaker but at different volumes.

Auxiliaries can also be used to connect external effects, recorders, and even subwoofers, but is most commonly used for monitor speakers.

aux


Want to learn more about speaker types?

Get a quick breakdown of speaker types and applications with our FREE speaker guide!

CLICK and READ: 5 SPEAKER TYPES EXPLAINED


9- Effects (pre/post fader)

Effects knobs are essentially an auxiliary knob with effects built-in. SImply raise the volume of the effects knob and there should be some effects added to that channel.

Effects knobs often have a button that is labeled pre and post.  

  1. Pre-Fader – The effects from the individual channel will be heard even if the volume fader on the channel is turned down
  2. Post-Fader – The effects from the individual channel will not be heard if the channels volume fader is turned down. In other words, the overall saturation of the effect is dependent on how the channels fx knob is set but if the channels volume fader is lowered the effect will be lowered as well.

fx


10- Pan

The pan knob is a way to move a sound to the left or right speaker.  In a more technical answer, the pan knob allows us to move the sound between the left and right channels of the sound system.  If we move the pan knob to the left on channel one, the vocals will only come out of the left speaker and not the right, because we are panning the vocals on channel one to the left output channel.  The pan knob simply moves a sound source between the left and right speakers.

pan


11- Mute

The mute button turns off the channel so that no sound is transmitted to the speakers.

IMG_2807
Mutes are can be labeled different ways but have the same function

12- Volume (Fader/Knob)

The volume knob or fader is located at the bottom of the signal chain.  This controls the volume sent to the speakers.  Remember the gain knob at the top of the channel is different from the volume knob at the bottom of the mixer.  The gain knob sets the volume for the channel, the volume knob sets the volume that we hear in the speakers.  

IMG_2802
Channel Volume Fader

13- Routing Options (PFL / L-R / 1-2)

Routing options refer to mixers that have subgroups.  If your mixer has subgroups then next to the channels volume fader there will be up to 4 buttons.  Each button will say 1-2, then below 3-4, and then the last button will say “main”.  Each of these buttons will send sound from the channel to either sub ground 1-2, 3-4, or the main output.  If these buttons are on your mixer, you will have to press the main button on each channel to hear each channel.  For instance, If the main button is not pressed then the sound from channel one will not go through the main speakers connected to the mixer.  Subgroups can be used in several different ways, the chapter over subgroups will go into further detail.

routing


In Summary of the Channel Strip Definition…

So now we know what a channel strip is and we know what every component on a channel strip does.  Now we can explain that a mixer is simply one channel strip duplicated horizontally.  Each channel is composed of the same components, everything from the mic input to the volume fader.


The Rest of the Mixer

Now that we have broken down the idea of a channel strip, the next part of this guide is focusing on outputs and best practices.  


Main Outputs Found on a Mixer

The main outputs on a mixer come in two forms,

  1. XLR Outputs- A balanced output that prevents humming and extra noise from coming out of the speaker system
    1. Use an XLR cable to connect to speaker/amp (commonly called a microphone cable)
  2. ¼” TRS Outputs- A balanced 1/4″ cable that helps prevent humming and extra noise from coming out of the speaker system
    1. Use a ¼” TRS to TRS cable to connect to speaker/amp
    2. Recommend to use ¼” TRS to XLR male cable to connect from the mixer to the speaker/amp

Auxiliary Outputs on a Mixer

Aux outputs are either labeled:

  1. Aux Send
  2. Monitor / Mon Send
    1. When an aux send is labeled mon or monitor send, it is because the manufacturer expects the user to connect what is called a Monitor Speaker to the aux output.  
      1. A monitor is a speaker placed on the stage, which is pointed towards the singer or musician, and it is used for the musician or singer to hear themselves.

Auxiliary outputs are generally ¼” TRS outputs.  The auxiliary output is generally used for monitor speakers which are used by musicians and singers to hear themselves on stage.


Aux Output Best Practices

  1. Aux output uses ¼” TRS cables
  2. A ¼” TRS to TRS cable can be used to connect to speakers/amps/external gear
  3. Recommend to use TRS to XLR Male cables to connect to speakers/amps/external gear
  4. An Aux is used to connect a monitor speaker
    1. A monitor is a speaker placed on the stage, which is pointed towards the singer or musician, and it is used for the musician or singer to hear themselves.
  5. An aux can be used to send audio to anything.
    1. Recorders, speakers, other rooms for audio, etc…

Auxiliary Send Master Knobs

Each aux send has a master knob found on the far right of the mixer.  The master aux knobs control the amount of overall volume from all channels that is sent to a speaker.  In other words, the “master aux knob one” is what controls the overall volume of every channel that has turned up the first auxiliary knob, the “master aux knob one” controls the overall volume of every channel that is sent to the speaker that is connected to the mixer output “aux send one”.  

Aux master knobs should simply be set at one volume which is generally in the middle, once the master aux knob is set in the middle, each individual channel can be easily added to a monitor speaker connected to an auxiliary output.


Effects Send Master Knobs

Effects send master knobs are used to control the overall volume of each individual channels fx send.  This is just like the aux send except the fx send knob sends sound to an effect that comes out of an fx return channel.

  1. Fx Return
    1. Is a fader on the mixer that must be turned up to hear the overall effect.  
    2. This helps control the amount of overall effect in the mix
    3. Helps make sure not to have an overwhelming amount of fx
    4. Keeps everything clear and easy to hear.  

Effects to Monitor / Aux

Next to the aux or FX master knobs, there is usually an fx to aux knob.  This knob allows the engineer to add effects to the monitor so that the singer or musician can have a little bit of extra inspiration to perform help add to the performance.  


Continue Expanding Your Audio Knowledge

Thanks for reading through our mixer layout guide! if you have any questions reach out to us via Facebook so we can help answer your questions and guide your mixer purchasing decisions.

facebook_logo_512px.png

What’s next in your audio engineering journey? Learn about INPUTS VS OUTPUTS & SIGNAL FLOW in our next blog post and become an expert for FREE by expanding your knowledge with our professional audio resources!

Take a picture or shoot a video of your audio system and any questions you may have by tagging us with #mychurchsound. Share your knowledge with our supportive audio community and be part of the solution!

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s