Installer’s Guide
Pink Noise Method
Pink noise
sounds rather like a waterfall. It contains equal energy per octave,
resulting in a flat response curve as measured with a
Real-Time Analyzer
(RTA). Since the
pink noise enters your sound system with its characteristic flat amplitude vs. frequency
curve, any irregularities in your system and room show up in the actual sound you hear. We
can analyze this response with a microphone and RTA.
•
No need for a calibrated microphone, just use your main stage mic. This covers
your entire reproduction chain, from mic to speakers to room. The least
expensive RTA might be a USB audio interface connected to a computer or laptop
running RTA software
.
•
The mixer’s built-in
Pink Noise Gen
can supply pink noise to any one channel, so
no external pink noise source is needed.
With your external equipment set up, you’re ready to run a Pink Noise adjustment:
•
Press
K
to toggle Pin
K
Noise ON. Choose the input to play pink noise through
(generally the channel supporting the most-used mic). Don’t use a channel that
has been converted to a Music input.
•
Turn up
only
this control until you get a good level at the RTA.
o
Note: Differing filter settings among your channels may cause
erroneous results when mixing several Pink Noise inputs.
•
Temporarily set this mic channel’s options (see page 28):
o
Disable gating
, switch
De-Ess OFF
, and
Compression ON
.
•
On your RTA, note the frequency and height of the largest peak.
•
Set a Voice Filter to its closest frequency. Experiment with this filter’s gain and
BW controls to minimize the peak.
•
Locate the next peak on the RTA, and then assign another Voice filter to cancel it.
•
Continue until the RTA curve is reasonably smooth. Attempting a perfectly flat
response is unnecessary and perhaps undesirable.
•
Return your mic to the stage and try it out with a helper speaking, as described in
the
By-Ear
method above. Make any additional adjustments by ear.
•
When all done, return this channel’s settings to those desired for regular use.
We have found that combining the two methods – starting out with
Pink Noise
and ending
with
By-Ear
adjustment – may yield better results than either method alone. You can also
try the
Auto-EQ
method (next page). In any case, you need not fret excessively over these
adjustments. If the sound system operates to your satisfaction, the equalization is good
enough! We have also found that overzealous EQ adjustments tend to reduce the overall
level, forcing operators to compensate by turning up mics – thus cancelling out the benefit.