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Low eq, Aux sends, Mute – MACKIE 1640 User Manual

Page 12: Channel fader, Signal level leds, Assign switches, Onyx 1640

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12

ONYX 1640

ONYX 1640

10. LOW EQ

This control gives you

up to 15 dB of boost or cut
at 80 Hz. The circuit is fl at
(no boost or cut) at the
center detent position.
This frequency represents
the punch in bass drums,
bass guitar, fat synth

patches, and some really
serious male singers.

Note: Used in conjunction with the Low Cut

switch, you can boost the LOW EQ without
injecting tons of infrasonic debris into the mix.

11. AUX Sends

These six knobs tap a portion of each chan-

nel’s signal out to either an effects processor or
for stage monitoring. The AUX Send levels are
controlled by the channel’s AUX 1-6 knobs, and
by the AUX MASTER 1-6 knobs.

These are more than just effects and monitor

sends. They can be used to generate separate
mixes for recording, for another zone, or “mix-
minuses” for broadcast or conference rooms.

12. PAN

PAN adjusts the amount of channel signal sent

to the left versus the right outputs.

With the PAN knob hard left, the signal feeds

the MAIN LEFT, SUB 1, or SUB 3 buses, de-
pending on the setting of the ASSIGN switches.
With the knob hard right, the signal feeds the
MAIN RIGHT, SUB 2, or SUB 4 buses.

Constant Loudness: The
Onyx 1640’s PAN control
employs a design called
“Constant Loudness.” If you
have a channel panned hard
left (or right) and then pan

to the center, the signal is attenuated about 3
dB to maintain the same apparent loudness.
Otherwise, it would make the sound appear
much louder when panned center.

13. MUTE

Engaging a channel’s MUTE switch provides (almost)

the same results as turning the fader all the way down
(a pre-aux send is not affected by the channel fader, but
it is by the MUTE switch). Any channel assignments to
MAIN MIX, SUB 1-2, or SUB 3-4 will be interrupted, all
the AUX sends will be silenced (both pre- and post-fad-
er), as will the AFL SOLO. The RECORDING OUT, chan-
nel INSERT, and PFL SOLO will continue to provide a
signal when a channel is muted.

The LED next to the MUTE switch lights to let you

know when the MUTE function is active.

14. Channel Fader

The fader controls the channel’s level…from off to

unity gain at the “U” marking, on up to 10 dB of addi-
tional gain.

“U” Like Unity Gain

Mackie mixers have a “U” symbol
on almost every level control. This
“U” stands for “unity gain,” meaning
no change in signal level. Once you

have adjusted the input signal to line-level, you can set
every control at “U” and your signals will travel through
the mixer at optimal levels. What’s more, all the labels
on our level controls are measured in decibels (dB), so
you’ll know what you’re doing level-wise if you choose to
change a control’s settings.

15. Signal Level LEDs

These LEDs indicate the channel’s signal level after

the GAIN control, INSERT jack, and EQ controls, but
just prior to the channel’s fader. So even if the fader is
turned down, you can see if a signal is present.

If you’ve followed the “Set the Levels” procedure, the

–20 and 0 LEDs should light frequently, the +10 LED
should light occasionally, and the OL (Overload) LED
should not light at all. If the OL LED is blinking fre-
quently, the signal is probably distorted from overdriving
the input. Either turn down the GAIN control or turn
down the signal at its source.

16. ASSIGN Switches

Alongside each channel fader are three buttons

referred to as channel assignment switches. Used in
conjunction with the channel’s PAN knob, they are used
to determine the destination of the channel’s signal.

With the PAN knob [12] at the center detent, the left

and right sides receive equal signal levels (MAIN MIX
L-R, SUB 1-2, and SUB 3-4). To feed only one side or the
other, turn the PAN knob accordingly.

20

Hz

100

Hz

1k

Hz

10k

Hz

20k

Hz

–15

–10

–5

0

+5

+10

+15

Low EQ

1

PAN

AUX

SEND

4

3

2

1

5

6

GAIN

FREQ

HIGH

12kHz

HIGH

MID

FREQ

LOW

MID

LOW

80Hz

EQ

OUT
IN

1

8k

400

2k

2k

100

400

U

+15

-15

U

+15

-15

U

+15

-15

U

+15

-15

O

O

O

O

MAX

O

O

MAX

O

O

MAX

O

O

MAX

O

O

MAX

L R

MAX

OL

+

10

0

-20

SUB

ASSIGN

MAIN

MIX

1-2

3-4

MUTE

SOLO