Mackie 800R owner manual Front Panel, Gain Control, MIC/LINE Switch, Phase Switch, Low-Cut Switch

ONYX 800R

Onyx 800R Features

Front Panel

There are eight channels in the Onyx 800R. They all share the same features with the exceptions that channels 1 and 2 have an impedance select switch and a mid/side decode switch, and channels 7 and 8 have a high-impedance 1/4" input jack for connecting electric instruments directly to the preamp without a direct box.

1. GAIN Control

The GAIN control adjusts the input sensitivity of the mic and line inputs. This allows the signal from the outside world to be adjusted to optimal internal operating levels.

If the signal is plugged into the XLR jack, there is 0 dB of gain (unity gain) with the knob turned all the way down, ramping up to 60 dB of gain fully up.

When connected to the balanced line input (DB25 connector), there is 20 dB of attenuation all the way down, and 40 dB of gain fully up, with a “U” (unity gain) mark at about 10:00.

2. MIC/LINE Switch

This button selects the input source from either the XLR MIC inputs or the DB25 LINE inputs. When the but- ton is out, the XLR MIC input is used and the line input is disconnected. When the button is pushed in, the DB25 LINE input is used and the XLR MIC input is disconnect-

ANCE switch allows you to change the input impedance of the microphone inputs on channels 1 and 2. This allows you to change the characteristics of the sound of the microphone.

There are four selections to choose from: A: 300 ohms,

B:500 ohms, C: 1300 ohms, and D: 2400 ohms. Select the impedance that is closest to the recommended imped- ance for your microphone. Or you can experiment with different settings and decide which one sounds best for your particular application.

Note: The 2400 ohm position (D) matches the nomi- nal input impedances of channels 3-8.

4. Phase Switch

Pushing in this switch simply reverses the polarity of the signal. This provides an easy way to correct a microphone whose polarity is opposite from the other microphones, either from a miswired cable or from not following the AES standard for Pin 2/Pin 3.

5. Low-Cut Switch

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.

ed. This way, you can leave signals connected to both inputs without having to disconnect one or the other, and the 800R acts as a patchbay for your input sources.

3.MIC IMPEDANCE Switch (Channels 1 and 2)

Many classic, vintage, and ribbon microphones are very sensitive to the input impedance of the mic preamp, and operate best at specific impedances. The MIC IMPED-

Channel 1

-20 0 OL		MID 1
0		300	Ω A
	48V	500	Ω B
		1300	Ω C
GAIN		2400	Ω D
		A B
30			C
20 U	40 LINE		D
U	60	MIC

+15

+10

+5

0

–5

–10

–15

20Hz100Hz

Low Cut

In live situations, this is useful for removing micro- phone handling noise or stage rumble. It can also be used to reduce the “prox- imity effect” with certain microphones that accentu-

1kHz	10kHz	20kHz	ates the bass frequencies
			when a vocalist gets too
			close to the microphone.
				Channel 8
-20	0	OL		8
0			48V	HI-Z
GAIN
20 U	30
			40 LINE

MIC/LINE

U60HI-Z (INST)

-20dB +40dB IMPEDANCE

-20dB +40dB

UNBAL

10

ONYX 800R