Mixing Desks

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Mixing Desks
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Inputs

• Microphone inputs
• Line inputs
• Tape returns
• Auxiliary returns
• Mix b inputs
• Insert points
• I/O

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Outputs

• Main outs
• Tape outs
• Insert points
• Auxiliary sends
• Group outputs
• I/O
• SAME AS TAPE OUTS ON SOME DESKS

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Overview of desk

• Live, monitoring, broadcast, recording
• Many configurations/conventions
• Naming convention
• Channels subgroups outputs
• i.e. 2482
• In line or split consoles

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In line configuration
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Overview of in-line desk
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Split configuration
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Overview of Split console
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Main input section

• Key features
• Input switching
• Attenuation
• Insert points
• Direct out

Pad (only on xlr i/p with no line in)
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Main input section
To EQ section
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Gain pot

• Key features
• Gain pot for line and mic inputs
• Flip switch for mic line
• Phase switch
• Phantom power
• Lo cut filter

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Input activity LEDs
Green LED shows -20dBu signal present Yellow LED
shows 0dB signal level Red LED shows potential
overload
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Why/How to set gain?

• Inputs from different sources
• Mic level (micro or milliVolts)
• Line level (nominally 0.775V)
• Tape machines
• Electronic instruments (synths etc)
• Either increasing or reducing gain
• Prevent distortion
• Different gain structure for mic/line

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Use Pre Fade Listen (PFL)

• Audition input signal
• Regardless of fader position
• With typical input activity
• Adjust gain pot until signal averages 0dB on the
  meters (yellow LED)

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example

• Microphone input gain 10dB to 60dB
• line input gain -10dB to 40dB
• If a mic provides 6mV with an input around 94dB
  SPL. How many dBs of gain would be required to
  bring the level up to nominal line level?

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Solution
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Equalisation
Next lecture
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Auxiliary sends

• Set up monitor mixes
• Side chain effects sends
• Individual channel send
• Mixed onto bus
• Master send for each aux (see later)
• Pre or post channel fader
• Usually Post eq post mute

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Auxiliaries

• Key features
• 8 auxiliary sends (gl3300)
• Two groups of 4
• Pre fade post fade switch

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Auxiliary sends
Channel
Aux Master faders
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Routing Muting

• Key features
• Pan control
• PFL button
• Mute button
• Channel fader
• Level LED indicators
• Routing buttons
• Mute group select

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Routing Muting

• Pan
• Control signal position
• Control routing to subgroups
• Mute
• Removes signal from any bus after channel fader
• Mute groups
• Select which mute groups the channel will belong
  to.

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Signal Routing

• Channel fader sets channel level to groups or
  main faders
• Routing buttons to determine signal destination
• Route to subgroup with switches
• Use pan to select odd or even subgroup
• Therefore selects tape track (default)
• Used to group signals or tracks together
• If we run out of subgroups ??
• Use direct outs
• No routing buttons, simply use patch bay

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Monitoring

• To monitor (listen to) signals being recorded
• Monitor tape returns (rather than direct signals)
• Mix b (in line desks) (limited facilities)
• Monitor section (split desks) (full facilities)

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Patch Bays

• Usually 48 jacks arranged in two rows of 24
• Method of interconnecting equipment in the studio
• Easily reconfigure connections
• Access to inaccessible connections

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Normalled
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Half normalled
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De-normalled
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Typical patch bay configuration
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Desk initialisation

• All buttons out
• All pots to centre détente position (Unity
  gain)
• Or fully anticlockwise (Gain and aux)
• Faders set to zero (-8)
• EQ set flat and switched out
• Patchbay all leads out
• Its your session take control of the desk and
  patchbay

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Fault finding

• Use your meters and LEDs to trace the signal
• Try to find where the signal is reaching and
  where it isnt
• Try another patch lead
• Try something you know works.

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VERY IMPORTANT

• DO NOT EVER unplug any leads from the back of ANY
  piece of equipment
• If there is any kind of problem, then ask the
  studio technicians Paul and Greg
• Or your lecturer

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Lots of other stuff

• Headphone mixes
• Slate
• Input impedance
• Output impedance
• Metering
• Output levels
• Distortion
• Crosstalk

• Talkback
• Oscillator
• monitoring
• noise
• Frequency response
• Automation
• Operating levels
• Low cut filter
• Matrix

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Further reading

• Sound and recording, Rumsey McCormick
• Chapters 6 7
• Practical recording techniques, Bartlett
• Chapter 12
• Sound recording practice, Borwick
• Chapter 7

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Online

• http//www.record-producer.com/learn/technology.cf
  m
• http//www.mackie.com/products/8bus/index.html
• http//www.behringer.com/02_products/prodindex.cfm
  ?idMX9000langeng
• http//www.allen-heath.com/gl3300.asp