Mackie 1640 4. GAIN Control, 5. EQ IN/OUT Switch, 6. HIGH EQ, 9. FREQ, 8. LOW MID EQ, 7. HIGH MID EQ, High EQ, HOWEVER:, Low Mid EQ, High Mid EQ, LOW MID EQ, and

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.

4. GAIN Control

If you haven’t already, please read “Set the Levels” on page 5.

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 1/4" jack, 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.

5. EQ IN/OUT Switch

This is a true hardware bypass of the Perkins EQ circuitry to insure that there is no coloration of the signal if the EQ is not needed. When this button is out, the EQ controls have no effect on the signal. You can use this switch to make an A/B comparison between the EQ’d signal and the signal without EQ.

We have completely redesigned theEQ circuits in the Onyx Series ofmixers, based on the designs of CalPerkins, an industry-leader in audio

engineering for over three decades and long-time Mackie collaborator.

This “neo-classic” design provides the sweet musicality of the British EQ sound, while still maintaining 15 dB of boost and cut with optimum Q and minimum phase shift (in other words, it gives you plenty of control and is pleasing to the ear!).

The 4-band equalization has LOW shelving at 80 Hz, LOW MID peaking, sweepable from 100 Hz to 2 kHz, HIGH MID peaking, sweepable from 400 Hz to 8 kHz, and HIGH shelving at 12 kHz. “Shelving” means that the circuitry boosts or cuts all frequencies past the speci- fied frequency. For example, rotating the LOW EQ knob 15 dB to the right boosts bass frequencies starting at 80 Hz and continuing on down to the lowest note you ever heard. “Peaking” means that the frequencies around the center frequency are less affected by the EQ the further away they are.

6. HIGH EQ

This control gives you	+15							Owners’
up to 15 dB boost or cut at	+10
12 kHz, and it is also flat	+5
	0
at the center detent. Use
it to add sizzle to cymbals,	–5
								Manual
and an overall sense of	–10
transparency or edge to	–15
the keyboards, vocals, gui-	20Hz		100Hz	1kHz		10kHz	20kHz
	High EQ
tar, and bacon frying. Turn
it down a little to reduce
sibilance, or to hide tape hiss.
7. HIGH MID EQ
Short for “midrange,”	+15
this knob provides 15 dB	+10
of boost or cut centered	+5
at the frequency deter-	0
mined by its FREQ [9]	–5
knob. Midrange EQ is	–10
often thought of as the	–15
most dynamic because the	20Hz		100Hz	1kHz		10kHz	20kHz
	High Mid EQ
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 fundamentals and
harmonics for many instruments.
8. LOW MID EQ
This is a second mid-	+15
range EQ control that pro-	+10
vides 15 dB of boost or cut	+5
centered at the frequency	0
determined by its FREQ	–5
knob. It extends down to	–10
100 Hz, which includes	–15
the male vocal range and	20Hz		100Hz	1k	Hz	10kHz	20kHz
	Low Mid EQ
the fundamentals of some
lower instruments (guitar, lower brass).
9. FREQ
This knob ranges from	+15
100 Hz to 2 kHz for the	+10
LOW MID EQ, and 400	+5
Hz to 8 kHz for the HIGH	0
MID EQ. This determines	–5
the center frequency for	–10
the EQ filter, and allows	–15
you to zero in on the	20Hz		100Hz	1k	Hz	10kHz	20kHz
	Mid EQ Freq Sweep
precise narrow band of
frequencies you want to have affected by the LOW MID
and HIGH MID EQ.
		Owner’s Manual						11