+15
13. LOW EQ
Mid EQ Freq Sweep
1kHz
100Hz
10kHz 20kHz
–15 20Hz
+10
+5
0
–5
–10
This knob ranges from 100 Hz to 2 kHz for the LOW MID EQ, and 400 Hz to 8 kHz for the HIGH MID EQ. This determines the center frequency for the EQ filter, and allows you to zero in on the precise
narrow band of frequencies you want to have affected by the LOW MID and HIGH MID EQ.
+15
12. FREQ
Low Mid EQ
1kHz
100Hz
10kHz 20kHz
–15 20Hz
+10
+5
0
–5
–10
This is a second midrange EQ control that provides 15 dB of boost or cut centered at the frequency deter- mined by its FREQ knob.
It extends down to 100 Hz, which includes the male vocal range and the funda-
mentals of some lower instruments (guitar, lower brass).
+15
11. LOW MID EQ
High Mid EQ
1kHz
100Hz
10kHz 20kHz
–15 20Hz
+10
+5
0
–5
–10
Short for “midrange,” this knob provides 15 dB of boost or cut centered at the frequency determined by its FREQ knob (see FREQ next), or at 2.5 kHz for the stereo channels. Midrange EQ is often thought of as
the most dynamic because the frequencies that define any particular sound are almost always found in this range. The HIGH MID EQ range (400 Hz to 8 kHz) includes the female vocal range as well as the funda- mentals and harmonics for many instruments.
+15
10. HIGH MID EQ

ONYX 1620

14. AUX Sends

These tap a portion of each channel’s signal out to either an effects processor or for stage monitoring. The AUX Send levels are controlled by the channel’s AUX 1-4 knobs, and by the AUX MASTER 1-4 knobs.

Since the AUX Sends are mono, the left and right signals in the stereo channels are summed together prior to the channels’ AUX 1-4 controls, sending the combined signal to the AUX SEND outputs.

These are more than just effects and monitor sends. They can be used to generate separate mixes for record- ing, for another zone, or “mix-minuses” for broadcast.

15. PAN

PAN adjusts the amount of channel signal sent to the left versus the right outputs. On the stereo channels (channels 9-16), the PAN knob works like the balance control on your home stereo (panning left turns down the right channel, and panning right turns down the left channel).

With the PAN knob hard left, the signal feeds either the MAIN LEFT (bus 1) or ALT LEFT (bus 3), depending on the setting of the ALT 3/4 switch. With the knob hard right, the signal feeds either the MAIN RIGHT (bus 2) or ALT RIGHT (bus 4).

Constant Loudness: The Onyx 1620’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.

+10

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

This control gives you

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

+5

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

up to 15 dB of boost or cut

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

at 80 Hz. The circuit is flat

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(no boost or cut) at the

–5

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

center detent position.

–10

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

This frequency represents

–15

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

20Hz

 

 

 

 

100Hz

 

 

 

 

 

1kHz

 

 

 

 

 

10kHz 20kHz the punch in bass drums,

Low EQ

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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.

 

 

 

 

 

 

 

12

ONYX 1620

 

 

 

16. MUTE/ALT 3-4

The dual-purpose MUTE/ALT 3-4 switch is a Mackie signature. When Greg was designing our first product, he had to include a mute switch for each channel. Mute switches do just what they sound like they do. They turn off the signal by “routing” it into oblivion. “Gee, what

a waste,” Greg reasoned. “Why not have the mute button route the signal somewhere else useful, like a separate stereo bus?” So MUTE/ALT 3-4 really serves two functions—muting (often used during mixdown or live shows), and signal routing (for multitrack and live work) where it acts as an extra stereo bus.

To use this as a MUTE switch, all you have to do is

not use the ALT 3-4 outputs (41). Then, whenever you assign a channel to these unused outputs, you’ll also be disconnecting it from the MAIN MIX, effectively muting the channel. The MUTE switch also disconnects the channel from the POST AUX SEND bus. The channel’s signal is still present on the PRE AUX SEND bus.