Mixers by fionan


An Introduction
              Mixers: Overview
   A mixer is a device that is able to accept signals
    from a wide variety of sources and then alter
    them in some way by changing their level,
    equalization and effects. The signals are then
    routed to output connections. This is most often
    to a pair of tracks (left and right), however most
    mixers present several options.

   Mixers take many forms from simple to
    extremely complex.
          Mixers: Applications

   Mixers are used in a wide variety of

   These include: live concerts, public
    address systems, recording studios, radio
    stations, DJs, television studios and film
    A mixer is divided into four main
    Input Connections

    Channel Strip

    Master Section

    Output Connections
             Input Connections
   This is the part of the mixer where the different
    sound sources are plugged in. These may
    include: microphones, direct boxes, guitars,
    keyboards, CD players and turntables.

   This is also the section of the mixer where
    effects devices are patched in. Examples
    include: compressors, reverb, chorus or delay.




A (XLR MICROPHONE INPUTS): Low impedance (resistance) , balanced microphone XLR input that
can also provide phantom power to a condenser microphone
Pin 1 : ground or shield
Pin 2 : Positive (+ or hot)
Pin 3 : Negative (- or cold)

B (1/4’’ LINE INPUTS): 1/4’’ input that can accept two different connections.

i) unbalanced/high impedance/TS (TIP/SLEEVE) connectors
ii) balanced/low impedance/TRS (TIP/RING/SLEEVE) connectors

C (LOW CUT switch): Cuts bass frequencies below 75Hz at a rate of 18dB per octave

D (TRIM): Adjusts the input sensitivity of the mic and line inputs.
i) XLR input can be boosted by 60 dB
ii) LINE input can be attenuated (brought down) by 15dB or boosted by 45 dB. “U” is when there
is no gain or attenuation to the signal
                                     F        G

E (STEREO LINE INPUTS): Fully balanced inputs that are used for stereo or
mono, balanced or unbalanced signals. These are often used to hook up stereo
signals from keyboards, tape/CD/MP3 players and sometimes effects devices.
Odd channel = LEFT and Even channel =right.

F (AUX EFFECTS SEND/RETURNS) : Used to connects the inputs and outputs of
effects devices (reverb/delay/compressor/chorus etc..)
AUX 1 can be used for stereo or mono effect
AUX 2 can only be used for stereo effects
There is also an option of using the SEND Outputs on either AUX to feed the
signal to monitors instead of effects.

hook up most types of audio players/recorders except for turntables. The
input signal is automatically boosted by 6 dB. The output line is used for
making a stereo recording (board mix) from the mixer‟s main outputs.


H (1/4” MAIN OUTPUTS): This is one of Two Main Stereo Outputs. Either
unbalanced (TS) or balanced (TRS) 1/4‟‟ connectors can be used.
TIP (T): + (hot)
RING (R):        - (cold)
SLEEVE (S):      Ground

I (PHONES OUTPUT): Used for listening to mixer‟s output with stereo
headphones with 1/4‟‟ (TRS) output.
                 Channel Strip
   This is the section of the mixer where basic
    adjusts are made to the incoming signal such
    as: effect level, equalization, panning, signal
    routing, and volume level.

   Most channel strips are used for an individual
    microphone or a mono instrument line. Some
    channel strips will accept stereo signals. Usually
    those on the far right of the console.
 AUX : Used to set the amount of signal that is
 sent to an external processor or to monitors.

           3 Band Parametric EQ :
 Hi : Boost or cut frequencies around 12000 Hz
                 (12kHz) by 15dB
MID : Boost or cut frequencies around 2500 Hz
                (2.5kHz) by 12dB
LOW : Boost or cut frequencies around 80 Hz by

PAN : Adjusts the amount of channel signal sent
          to the left vs. right outputs.

Dual purpose MUTE/ALT 3-4 Switch: Will silence
the channel or send the signal from this channel
              to the ALT 3-4 bus.

SOLO switch: Silences all other channels except
                 for this one.

 CHANNEL FADER : Controls the channel level
  from Unity Gain (U) up to 10 dB of boost or
                 down to oo
              Master Section
This is the control centre of the mixing board.

a)   level adjustments are made: effects, stereo
     output (L/R), ctr room/submix outputs (L/R).
b)   meters and lights indicate: mixer power,
     phantom power, rude solo light, VU meters.
c)   signal routing options are chosen: pre/post
     efx, efx to monitors, control room/submix
     signal source.
    J   K   L   J ( AUX 1 MASTER) : Provides overall control of signal that
                is sent from the AUX SEND 1 output. AUX SEND 2 has no
                output dial !

                K (EFX TO MONITOR) : Used to send EFX from AUX SEND
M               2 into AUX SEND 1.

N               L (AUX RETURNS): Sets the amount of effect coming in
                from the AUX RETURNS 1 and 2

                M (AUX 1 SELECT) : Allows you to choose whether you
                want to tap the signal that is to be effected either PRE-
O               FADER/UP (most common when used for monitoring) or
                POST-FADER/DOWN (usually only used for effects when
                you want the “wet” signal to follow the “dry” signal).
                N (CONTROL ROOM/SUBMIX MATRIX): Buttons that
                allow the engineer to quickly route the MAIN MIX, ALT 3-
                4 selected channels, or the TAPE INPUTS to the Control
                Room/SubMix/Phones Outputs. Any combination of these
                may be chosen simultaneously.

                O (ASSIGN TO MAIN MIX): Feeds the C-R/SOURCE
                Selections into the MAIN MIX.

                P (SOLO MODE) : This is used to set Pre-Fader Listen
                (PFL) and After-Fader Listen (AFL) levels on the VU
                LIGHTS): Allows the engineer to know when
                phantom power or the mixer is itself is turn on.
                R (VU METERS): Displays volume units for specific
                signals that are chosen in the C-R/SOURCE matrix
                or soloed channels.
Q           U
                S (CONTROL ROOM/SUBMIX): Sets master level of
                CONTROL ROOM/SUBMIX

                T (MAIN MIX): Sets overall level of the MAIN MIX

                U (RUDE SOLO LIGHT): This light reminds the
                engineer if any of the channels are in solo mode.

    S   T
              Output Section

   This is the portion of the mixer where
    different cables are patched in to feed the
    signal to other sources. This could be:
    power amplifiers, speakers, recording
    devices, effects, headphones or other
 V    W X


V (POWER CONNECTION and FUSE BOX): Internal power
supply that powers the mixer. Accepts a standard 3 prong
IEC power cord. Below is a compartment that houses a 0.5
amp fuse.

W (POWER SWITCH) : Turns mixer power on and off.

X (PHANTOM POWER SWITCH) : Turns phantom power
for condenser microphones on and off.

Y (XLR MAIN OUTPUTS): Left and Right XLR/low
impedance/ Balanced Output that are controlled by the
MAIN MIX fader.
                        Z    AA       BB             CC
Z (MAIN OUTPUT LEVEL PAD): Lowers the signal
level from the MAIN OUTPUTS by 30 dB. This is
helpful when feeding the main mixer signal to
another mixer.

AA (1/4 „‟ CONTROL ROOM OUTPUTS): Balanced or
unbalanced 1/4‟‟ output whose level is controlled

BB (1/4 „‟ ALT OUTPUT): Balanced or unbalanced
1/4‟‟ output for any channels where the MUTE ALT
3-4 button is selected.

CC (CHANNEL INSERTS): Allows certain effects to
be connected to single channels using a TRS Insert
Cable . This is used most often for compressors,
filters, equalizers and de-essers.

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