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SOUND 1 |
MACKIE ONYX1640i MIXER |
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INTRODUCTION: |
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There are many terms used to refer to the complicated-looking piece of electronic gear sitting on the table in front of the Sound Booth window: console, mixer, mixing board, sound board, mixing desk, sound desk. [I will try to be consistent and to always refer to the mixer. If I slip up, you now know the other possible terms.] |
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In a production studio, the mixer is used to route sound signals from various sources, (microphones, CD players, FX units) to various destinations (usually tape machines, hard disk recorders or FX units). It can also be used to modify the tonal quality (EQ) or relative balance of the sound signals passing through it. |
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In a performance space, the mixer serves to route the various sound sources (microphones, CD players or FX units) to various loudspeakers on the stage or throughout the house. It allows you to control where the sounds will be heard and how loud they will be. |
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The same mixer will generally serve for either the production studio or performance space. One of the mixers we have at John Abbott is a MACKIE ONYX1640i MIXER, manufactured in the U.S. It is representative of mixers you will find in many production studios or theatre spaces today. |
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In addition to its use as a live
sound mixer, the 1640i also can also serve as a
bidirectional, 16
channel sound interface for a computer. A single
Fire Wire cable
connects the mixer to the computer. Sections involving
Fire Wire are highlighted like this one. |
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MACKIE ONYX 1640i MIXER: In a sound system, a source of
sound is referred to as an output. A
destination is referred to as an input.
Building a sound system involves connecting sources to
destinations -- an output to an input to an
output to an
input.....and so on.The sources could be the outputs of mics. on stage, CD players, effects units or tracks from a computer. The destinations could be the inputs of
the
House speaker system, onstage monitors, headphone amps
or effects units. The MACKIE mixer
allows you
to simultaneously control and route, any (one or more)
of sixteen sound
sources to any of six main
destinations; the MAIN
MIX, SUB1-4
outputs and/or to any
of six auxiliary destinations; the
AUX1-6 outputs. In a sort of technical short-hand, this mixer may referred to as a 16:4:2 mixer (with 6 auxiliaries) to indicate it offers 16 inputs, 4 subs and 2 main outputs (with 6 auxiliaries).
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Although the mixer may appear to be complicated, it is in fact, composed of only a few different building blocks or strips. Each type of strip groups together all the controls and internal circuitry to perform similar functions. In our mixer, the 16 input strips are grouped together on the left side of the mixer. The 4 sub strips and single main strip are on the bottom right. The monitor and aux master strips are located above the sub and master modules. You will only need to learn the operation of these few strips, in order to "master" operation of the entire mixer. We'll have a look at the front
panel controls and the signal
flow through each of the modules in turn.
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INPUT MODULES: |
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The 16 mono input modules or strips, to the left of our mixer, are indicated by white fader knobs. | ||||||
The
"LINE/FW" switch selects either the analog input or the
digital return
from the computer as the source to the input channel. |
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Some condenser or electret type microphones can be powered externally, eliminating the need for batteries. The power required can be supplied by the mixer via the same cable used to carry the microphone signal to the mixer. This
system is called phantom powering. The "48V" switch on
each input
channel activates this function. The
LED above the switch indicates
that phantom power is activated for that channel. |
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In
certain cases, supplying 48 volt power to a microphone
not requiring
it may result in noise or hum (at best) or damage
to the
microphone
(at worst).
Phantom powering should only be activated if you know you need it for a given microphone. |
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LOW CUT
(High Pass Filter):
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Input
channels
1 and 2 have an additonal switch to configure the input
to accept the output of a musical instrument
(guitar, keyboard). |
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The "GAIN" control
allows you to adjust the input strip so that you can
operate with the
white channel fader in its normal
range, around "-U-" on the scale. This assures that the
signal will
have the maximum headroom and minimum noise. (See
"SOLO" button
below.) Headroom
is
the
level
difference
available
between normal level and the point of distortion.
Noise is the
background hiss you hear when you turn the
gain or volume up too much.
At the "-U-" setting, there is still 10 dB of gain available, should the input signal drop in level. We say that there is 10 dB of gain-in-hand. This gives you room to maneuver should the input signal change. Working at "-U-" also allows for smooth
fades
in or out.
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Input Channel EQ: | ||||||
The
FireWire "SEND" switch selects the feed to the computer
either PRE or
POST EQ -- before or after the action of the channel
equaliser. |
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HIGH: Shelving |
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HIGH MID:
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LOW MID:
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LOW: Shelving |
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EQ
(IN/OUT): Allows the operator to activate or deactivate the equaliser on each channel. |
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AUX Sends:The controls
labeled "AUX" allow
you to send a part of the signal from any input channel
strip to any of
six additional outputs. These outputs can be used to
feed a separate
mix to program sound, monitors onstage, headphones in
the studio, or to
the sound
processing and effects devices in the control room.
AUX sends
can be taken before or after the channel fader. We
call these
feeds PRE fader or POST fader. POST fader
sends
are used to feed
reverb
devices where you would want the strength of the reverb
effect to
follow the level as controlled by the channel
fader. PRE fader
sends are for feeding headphones
for instance. You wouldn't necessarily want the mix in
the headphones
to change as you trim the recording or house levels. On
the Mackie 1640i, global switches on the AUX MASTER
strip select
PRE or POST fader operation for each of the AUX
busses. That
means that all of
the input
channels feeding a particular AUX buss will be either
PRE or POST.
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Routing Section: |
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The "MUTE" button
de-activates the
entire input strip.
Light emitting diodes (LED) labeled "-20", "0","+10", and "OL" indicate the level of the input signal. "OL" stands for OverLoad. If the "OL" LED flashes briefly every couple of minutes, the signal level is not too high. If it flashes continually, you will have to reduce the input signal to avoid distortion.
The signal level indicated is independent of the position of the input fader and allows you to roughly set the position of the "GAIN" control to an optimum position. The signal
passing
through
the input strip can be routed to the Left and
Right MAIN MIX
outputs by
pressing the "L-R" button. The "PAN" control (short for
panoramic
potentiometer)
allows you to
send the signal to anywhere in the sound field between
the left and
right outputs. The buttons "1-2", "3-4", allow the
signal to be sent
to any pair of sub outputs. The odd numbered outputs are arbitrarily considered as left and the even numbered ones as right. If you depress the "1-2" button and pan fully left; the signal will go only to SUB 1. Panning right will assign the signal to SUB 2 only. Midway between left and right will assign the signal somewhere between SUBs 1 and 2. The white sliding control is the input channel fader. This is your operational control over the signal level during a recording or performance. It allows you to smoothly fade an individual sound in or out. The "SOLO",
button
routes the input
signal directly to the left/right meters and monitor
speakers (or
headphones) and
illuminates the large red indicator labeled "RUDE
S0L0". These meters have much greater resolution
than the four LEDs on the input channel. With "SOLO" in, start with the "GAIN" control fully counter-clockwise. As someone talks into the microphone or while you play the loudest cut of your show CD; rotate "GAIN" until the meters are just reaching the -0- VU point. Don't forget to release the "SOLO" button afterwards!
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SUB STRIPS: |
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The "SUBS TO FW 5-8" switch allows the 4 SUB outputs to be sent to the computer on channels 5-8. | |
MAIN (L-R) STRIP: |
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The "MAIN" fader controls the signal from the MAIN (L-R) output. | |
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TALKBACK: |
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The mixer's built-in
microphone
"MIC" allows you to talk to the talent through headphones
or stage
monitors. The "DESTINATION" switches determine where the talkback signal will be sent -- headphones plugged directly into the "PHONES" jack on the console or headophones or stage monitors plugged into one or more "AUX 1-6" outputs. The "LEVEL" control allow you to adjust the talkback volume heard by the talent. Start withthis control at minimum and slowly increase it while holding the "TALKBACK" button; until you are clearly heard. |
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AUX MASTER STRIP:
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The "SENDS 1-6 TO FW 9-14" button routes the AUX SENDS via Fire Wire to inputs 9 to 14 of the computer software. | |
AUX SEND MASTERS 1-6: | |
To
the left are the "AUX SEND 1-6" master
controls. The "SOLO" buttons route the
respective AUX signal to the control room monitor. The
"PRE/POST"
buttions determine if each AUX is sent pre or post
(i.e. before
or after) the AUX SEND
master controls.
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AUX RETURNS 1-4: | |
To the right are the four
stereo AUX
RETURNS. These allow you to send the stereo
outputs (returns) of
four separate FX processors to the MAIN MIX outputs.
AUX RETURNs 1 and 2 can be returned to AUX SENDs 5 and 6 respectively, in addition to, or instead of, the MAIN MIX. This could be used to send reverb to stage monitors, for instance. AUX RETURN 3 can be returned to the MAIN MIX, or to SUBs 1-2 or 3-4. We can use SUB 3-4 to add reverberation to the ROH (Rear Of House) speakers, making the theatre sound more "live". AUX RETURN 4 can be sent to the MAIN MIX, or only to the Control Room and Phones outputs. This way, the audience won't hear it. The POWER LED indicates that the mixer is powered. |
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MONITOR STRIP:
"CTRL
ROOM/PHONES SOURCE" buttons select the source for the
Control Room
monitors:
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"FW 1-2" sends Fire Wire 1-2 outputs of
the computer only to the "CTRL
ROOM/PHONES". "ASSIGN TO MAIN MIX" sends Fire Wire 1-2 outputs of the computer directly to the Main Mix. |
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"CONTROL ROOM" sets the volume for the
Control
Room monitor speakers. "PHONES" (headphones) sets the volume
for the
"PHONES" jack. "TAPE IN" adjusts the volume of the
external
"TAPE IN" signal. "TAPE TO MAIN MIX" feeds it to
the "MAIN
MIX". The large red LED labelled "RUDE SOLO" indicates one of the "SOLO" buttons has been activated. The "SOLO LEVEL" controls adjusts the volume of the
"SOLO"
buss. There are two
SOLO modes on the Mackie,
The "SOLO MODE" button selects between the
two. We normally use "PFL".
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REAR PANEL CONNECTORS: |
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CHANNEL INPUTS:
Audio
signal levels fall into one of two categories.
There is a difference of 40 or 60 decibels (dB) between microphone level and line level signals. Either
type of signal must be connected to the mixer via the
appropriate jack
or socket.
Microphone
level
signals connect to the three-pin XLR-type
female connectors. Line level signals connect to the 1/4
inch TRS
jacks. DO NOT
connect to both on the same input channel.
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AUX RETURNS INPUTS:Connect to outputs of FX
processors.
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SUB OUTPUTS:Connect to inputs of
upstage, ROH
loudspeaker systems.
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CONTROL ROOM OUTPUTS:Connect to Control Room
(Booth)
monitor speaker system.
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MAIN OUTPUTS:Left, Right connect to
inputs of proscenium (FOH) loudspeaker systems. Mono
connect to Centre FOH.
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AUX SEND OUTPUTS:Connect to inputs of FX
processors, stage monitors.
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FIRE WIRE CONNECTIONS:Connect to computer Fire
Wire
card.
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MIXER BLOCK DIAGRAM: |
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LINKS:Mackie Onyx 1640i --
Track Sheet -- Print these sheets to record your
show presets.
Mackie Onyx 1640i -- Block Diagram Mackie Onyx 1640i -- Fire Wire I/O Mackie Onyx1640i -- Owner's Manual -- Read this attentively to really understand the mixer's operation. Mackie Onyx1640i -- Quick Start Guide -- Consult this link in a panic. |