Mixing Consoles
Designations
Inputs
Outputs
Signal processing
Sound Control Mixer - Heart of the Audio System
Mixer - Heart of the Sound system Sound Board, Audio Console, Mixing desk
Main tool of the operator (Board Operator) Basic Purpose - Controls
What is it - Selects audio signals from various sources Devices are connected to input channels Microphones Output channels of CD players, MD players, DAT players,
computers How Loud will it be - Controls signal level (volume) Where is it going - Sends audio to various locations
Devices are connected to outputs Power amplifiers Input channels of MD players, DAT players, Computers
Sound Control Mixer - Heart of the System
Mixer Nomenclature (Functional Description) 8x2 = 8 inputs and 2 outputs 16x4 = 16 inputs and 4 outputs 16x4x2 = 16 inputs, 4 group of sub outs, 2 main outs.
Can be used as: 16 ins mixed down to 4 sub mixes, mixed down to 2
output channels (recording studio or concert presentation) utilization
24x6 (Theatre type utilization) 16x4x2x1 – adds a mono output
Also can be referred simply by the number of input channels ex. 8, 16, 24, 48 etc…
Cue Control Audio System – Sources, Control, Destinations
Equipment System is the Primary Tool of Modern Theatre Sound Design: Block Diagram - Foreigner Setup
Upstage L/R
Cluster
RadioRecordPlayer
MD 1
MD 2
Cass
Computer
MixerAmp
Amp
Amp
1-2
3-4
5-6
7-8
Input Channels
1 - 2
L/R
Mono
3
Group/ Outs
Input Buss
This is the section where audio signals from microphones and/or playback equipment enters the mixer
This is the area where impedance matching and Balanced / Un-balanced lines must be carefully watched
The input buss typically starts at the rear of the console with either XLR or ¼” TRS connectors
Input Buss
Input Buss
Rear view of a Mackie t24
Input Buss
The front side of the console will differ from manufacturer to manufacturer but they will have most of the same components
The input channel will usually be arranged to follow the virtual signal path
Input Buss
Pre-amplifier Pre-amp, trim, trim pot, gain Used to bring a microphone level signal up to line
level for easy manipulation within the mixer Also used to adjust the line level inputs from other
sources Pad or Attenuator
A switch which will lower an inputs level by a set amount
Usually used in an input device is too “hot” or much too high a level
Close up of Pre-amp section
Input channel #
Pad / low end roll off
Gain adjust
Equalization section Onboard equalization control will vary greatly
Simple “tone” control Simply varies the balance between high and low frequencies
Treble and Base Boost or attenuate high frequencies (treble) or low frequencies (base) Only adjusts a preset range of frequencies
Hi – Mid – Lo A fancier version of treble and base control
5 band EQ Able to boost of attenuate 5 different ranges of frequencies
Parametric EQ Able to select which frequency range to control and then boost or cut
it
Equalization sectionHigh freq. control
High-mid with selectable frequency range
Low-mid with selectable frequency range
Low frequency control
Auxiliary Sends Next in line comes a number of Aux sends
Typically 4 to 8 individual busses Some or all will be pre or post fader selectable
Pre-fader – the signal strength (volume) coming from the aux send channel will be independent on the position of the channel fader
Post-fader – the signal strength coming from the aux send will be dependent on the position of the channel fader
Often labeled as PFL (Pre-Fade Listen) Often used to send signals to other devices
External effect processor Reverb or echo
Monitor amp/speakers for performers
Auxiliary Sends
8 individual aux send channels
Note the pre-fade switch
Signal Routing Each input channel will be assignable to one or more output
channels Very often one selector button will assign the input to two separate
outputs 1-2 or 3-4 for example The Pan Pot (Panoramic Potentiometer) adjusts the level of signal going
to each of the pairs Example: With the pan pot centered and 1-2 selected, the entire signal is sent
to outputs 1 and 2 equally. If you turn the pot to the left, more signal will be sent to output 1 than output 2
This is usually to be avoided for theatrical use Look for single output selection control if possible
PFL – Pre-fade Listen. Sometimes called “solo” Usually available to send the signal to a studio monitor or headphones to
allow operator to listen to channel without having to send it into the house
Channel Mute – turns the channel off. Useful when using wireless mics
Signal Routing
Pan Pot
Output selection
Mute
Note: PFL not available on this model
Other input controls
Phantom power A 48v DC power supply applied to the mic input lines
Used to power condenser mics (to be discussed later) Phase reverse
Inverts the signal coming to the inputs Used if pins 2 and 3 on a mic cable are reversed for
example Ground lift
Removes the ground connection at the console from the input cable Used to help eliminate ground-loop noise
To be discussed during troubleshooting
Output Section
This is the area where audio signals will leave the mixer, heading toward Effects processors
EQs, delay units, reverb units, recording devices Power amplifiers and eventually loudspeakers Output plugs will typically be
Balanced XLR line level Balanced TRS line level Unbalanced ¼” phone plug line level Unbalanced RCA plug line level
Output Section
Sub or group outputs
Auxiliary outputs
Left, Right and Main outputs
Output Section Sub-group output faders
Sometimes called groups, subs or submasters Act as a master fader control for any inputs assigned to it Typically these are cabled to power amplifiers
Main outputs Sometimes called Left-Right, Stereo or Mix Essentially two additional outputs, where the manufacturer has
taken a guess as to what the end user will use them for Sub groups can usually be combined and selectively assigned to
the main output Master output
Sometimes called Mono The main outputs can be combined together and controlled from
one master fader
Aux-Output Section
Aux out gain control
Aux out mute switch
After fader listen
Group-Output Section
“Flying Faders”
Automated mixers are becoming more and more common
Started simply to record levels in recording studios Often had 60 or more inputs levels to write down
and could have many many setups. Flying faders would remember where the faders
were set and you could restore to any setting with the push of a button
“Flying Faders”
Today mixers are capable of remembering output selections, EQ settings, pan settings etc.
For live mixing it is REQUIRED to still have actual faders which an operator can move Performers will never do the exact thing every
night The board operator must be able to easily make
adjustments to levels on the fly
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