Mackie Onyx 1220 Channel Strips, 4. MIC/HI-ZSwitch, 5. Low-CutSwitch (Channels 1-4), Low Cut, Mono Channel

Low Cut

100Hz

+15

+10

+5

0

–5

–10

–15 20Hz

1kHz

10kHz 20kHz

1220	Onyx 1220 Features
	Channel Strips
ONYX
	There are two kinds of channel strips on the Onyx 1220:
	Mono and Stereo. The mono channel strips (channels
	1-4) have mic and line input connectors. In addition,
	channels 1 and 2 have high-impedance instrument
	inputs so you can connect a guitar directly to the mixer.
	The stereo channel strips (channels 5-12), have two
	line input connectors per channel strip, left and right.
	The stereo path is maintained throughout the channel
	strip, sharing the channel’s controls (the controls work
	on both left and right signals at the same time).

Note: For the stereo channels 5-12, if a signal is plugged into the LEFT (MONO) side and nothing is plugged into the RIGHT side, the signal is automatically connected to both LEFT and RIGHT sides. This is called jack normalling. As soon as something is plugged into the RIGHT side, the normalled connection is broken and the LEFT and RIGHT inputs become stereo inputs (LEFT goes to the LEFT MAIN OUT and RIGHT goes to the RIGHT MAIN OUT).

4. MIC/HI-Z Switch

Channels 1 and 2 have an extra button for switching between the MIC and HI-Z inputs. When the button

1

NYX MIC	P
O
	RE

HI-Z

1

MIC

HI-Z

48V

20 U	30
	40

U 60

-20dB +40dB

GAIN

	OUT		EQ
	IN
	U
		HIGH
			12kHz
-15	+15
	1k
			FREQ
100	8k
	U
			MID
-15	+15
	U
			LOW
			80Hz
-15	+15
		AUX

	1
OO	MAX
	2
OO	MAX
	PAN

L R

MUTE

ALT 3/4

Mono Channel

1. MIC Input (Channels 1-4)

This is a female XLR connector, which accepts a balanced microphone input from almost any type of microphone. The microphone preamps feature our new Onyx design, with higher fidelity and headroom rivaling any standalone mic preamp on the market today.

The XLR inputs are wired as follows: Pin 1 = Shield or ground

Pin 2 = Positive (+ or hot) Pin 3 = Negative (– or cold)

2.HI-Z Instrument Input (Channels 1-2)

This is a 1/4" connector, which accepts an unbalanced instrument-level input signal from a high-impedance instrument like a guitar.

3. LINE Input (Channels 3-12)

This is a 1/4" TRS connector, which accepts a balanced or unbalanced line-level input signal from almost any source.

When connecting a balanced signal to the LINE inputs, wire them as follows:

Tip = Positive (+ or hot) Ring = Negative (– or cold) Sleeve = Shield or ground

When connecting an unbalanced signal, wire them as follows:

Tip = Positive (+ or hot) Sleeve = Shield or ground

is out (MIC), the XLR MIC input is used and the HI-Z input is disconnected. When the button is pushed in (HI-Z), the 1/4" HI-Z input is used and the XLR MIC input is disconnected. The input stage of the HI-Z inputs is specially designed for the high-impedance pickups on guitars.

Plugging a guitar into a lower-impedance

line input (like those on channels

3-16) can result in the loss of high

frequencies, causing an unnatural and

dull sound. Normally, you must use a direct box between a guitar and a

mixer’s input, which serves to convert the impedance of the guitar from high to low. The HI-Z inputs on channels 1 and 2 make the need for a direct box unnecessary. HOWEVER: The HI-Z inputs are unbalanced, so if you’re doing a live show and running a long cord between the instrument and the mixer (say over 25 or 30 feet), it is best to use a direct box with a balanced output to avoid picking up noise over the length of the cord.

5. Low-Cut Switch (Channels 1-4)

The Low-Cut switch, often referred to as a high-pass

filter, cuts bass frequencies below 75 Hz at a rate of 18 dB per octave.

We recommend that you use the Low-Cut filter on every microphone application except kick drum, bass guitar, bassy synth patches, or record-

ings of earthquakes. These aside, there isn’t much down there that

you want to hear, and filtering it out makes the low stuff you do want much more crisp and tasty. Not only that, but the Low-Cut filter can help reduce the possibility of feedback in live situations and it helps to conserve the amplifier power.

10 ONYX 1220