Mackie ProFX8 User Manual

Owner’

s Manual

Another way to consider low cut’s function is that it 

actually adds fl exibility during live performances. With 
the  addition of low cut, you can safely use low EQ on 
vocals. Many times, bass shelving EQ can really ben-
efi t voices. Trouble is, adding low EQ also boosts stage 
rumble, mic handling clunks and breath pops. Low cut 
 removes all these problems so you can add low EQ with-
out losing a woofer out the window.

The ProFX mixer has 3-band equalization at carefully 

selected points — low shelving at 80 Hz, mid peaking at 
2.5 kHz, and high shelving at 12 kHz. “Shelving” means 
that the circuitry boosts or cuts all frequencies past the 
 specifi ed frequency. For example, rotating the low EQ 
knob 15 dB to the right boosts bass starting at 80 Hz and 
continuing down to the lowest note you never heard. 
“Peaking” means that certain  frequencies form a “hill” 
around the center  frequency — 2.5 kHz in the case of 
the mid EQ.

The following graphs of frequency vs. signal level show 

the approximate overall effect of EQ adjustment on the 
frequency range.

This control gives you 

up to 15 dB boost or cut 
above 12 kHz, and it is fl at 
(no boost or cut) at the 
detent. Use it to add sizzle 
to cymbals, and an overall 
sense of transparency, or 
edge to keyboards,  vocals, 
guitar and bacon  frying. Turn 
it down a little to reduce  sibilance, or to hide tape hiss.

Short for “midrange,” 

this knob provides 15 dB 
of boost or cut, centered at 
2.5 kHz, also fl at at the cen-
ter detent. 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. 
You can create many interesting and useful EQ changes 
by turning this knob down as well as up.

This control gives you up 

to 15 dB boost or cut below 
80 Hz. The circuit is fl at at 
the center detent position. 
This frequency represents 
the punch in bass drums, 
bass guitar, fat synth 
patches, and some really 
serious male singers. 

Used in conjunction with 

the low cut [22] switch, 
you can boost the low EQ 
without injecting a ton of 
subsonic debris into the 
mix.

With EQ, you can also upset things royally. We’ve de-

signed a lot of boost and cut into each equalizer circuit, 
because we know everyone will occasionally need that. 
But if you max the EQs on every channel, you’ll get mix 
mush. Equalize subtly and use the left sides of the knobs 
(cut), as well as the right (boost). Very few gold-record-
album engineers ever use more than about 3 dB of EQ. 
If you need more than that, there’s usually a better way 
to get it, such as placing a mic differently (or using a 
different kind of mic entirely).

These knobs tap a portion of each channel's signal 

to set up a nice monitor mix feeding stage monitors, 
independent of the main mix. Adjust these controls on 
each channel until your band is happy with the stage 
monitor mix.

The aux mon feed from hybrid and stereo channels is 

a mono sum of the left and right sides of these channels.

The controls are off when turned fully down, deliver 

unity gain at the center detent, and can provide up to 15 
dB of gain turned fully up.

The channel fader [31], pan [28], or mute [30] do 

not affect the monitor output, but the other channel 
controls will. (The aux mon is pre-fader.)

The monitor signal from the monitor output jack [13] 

is the sum (mix) of all the channels whose aux mon 
control is set to more than minimum. The overall output 
level can be adjusted with the monitor fader [47] and 
its EQ tweaked with the graphic EQ [37] if the main 
mix/mon switch [38] is pressed in. Internal FX can also 
be added to the monitor mix with the FX to mon knob 
[54].