MACKIE 1640 - Manual (Page 11)

11
Owner’s Manual
Owner
’s Manual
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 cir-
cuitry 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 the
EQ circuits in the Onyx Series of
mixers, based on the designs of Cal
Perkins, 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-
fi ed 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
up to 15 dB boost or cut at
12 kHz, and it is also fl at
at the center detent. Use
it to add sizzle to cymbals,
and an overall sense of
transparency or edge to
the keyboards, vocals, gui-
tar, and bacon frying. Turn
it down a little to reduce
sibilance, or to hide tape hiss.
7. HIGH MID EQ
Short for “midrange,”
this knob provides 15 dB
of boost or cut centered
at the frequency deter-
mined by its FREQ [9]
knob. Midrange EQ is
often thought of as the
most dynamic because the
frequencies that defi ne 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-
range EQ control that pro-
vides 15 dB of boost or cut
centered at the frequency
determined by its FREQ
knob. It extends down to
100 Hz, which includes
the male vocal range and
the fundamentals of some
lower instruments (guitar, lower brass).
9. FREQ
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 fi lter, 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.
20 Hz 100 Hz 1k Hz 10k Hz 20k Hz
–15
–10
–5
0
+5
+10
+15
High EQ
20 Hz 100 Hz 1k Hz 10k Hz 20k Hz
–15
–10
–5
0
+5
+10
+15
High Mid EQ
20 Hz 100 Hz 1k Hz 10k Hz 20k Hz
–15
–10
–5
0
+5
+10
+15
Mid EQ Freq Sweep
20 Hz 100 Hz 1k Hz 10k Hz 20k Hz
–15
–10
–5
0
+5
+10
+15
Low Mid EQ