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k.
Press the Generator button again to turn off the generator.
5.
Press Auto EQ to automatically equalize this channel. The Auto EQ sequence will put up
messages showing the progress of the equalization.
6.
Select the next channel to be equalized and press Auto EQ again. Repeat this until all
channels are equalized.
8.11.4
MANUAL EQUALIZATION
A suggested procedure for equalizing a channel is listed below. Your theater may use a
modified or different procedure. If an external pink noise generator is to be used with the
internal RTA, enable the internal pink noise generator, then disable it. Enabling the internal pink
noise generator configures the internal RTA for proper operation.
1.
Connect four microphones to a microphone multiplexer such as the USL MMP-‐10. Position
the microphones as specified in SMPTE 202-‐2010 sections 5.2 and 5.3.
2.
Connect the microphone multiplexer output to the microphone input of the JSD-‐60.
3.
On the Equalizer tab, press the Curve File button and select the appropriate curve file (such
as x-‐curve 150 seats.ini). This sets the limit lines on the RTA display.
4.
Press Mic File to load a previously generated microphone calibration file, or calibrate the
microphones as described below:
a.
On the equalizer tab, select the center channel.
b.
Set the gain control at the far left of the equalizer to minimum.
c.
Set the main fader to 0.0.
d.
Press the Flatten button.
e.
Press Pink and Generator to drive the center channel with pink noise.
f.
Adjust the main fader towards 7.0 without exceeding 85dB SPL in the auditorium.
g.
Adjust the gain control at the far left of the equalizer tab to yield 85dB SPL in the
auditorium as measured by a reference SPL meter.
h.
Press the Mic Cal button to bring up the microphone calibration dialog box.
i.
Adjust the Microphone Gain control in the microphone calibration dialog box until the
JSD SPL agrees with the reference SPL meter.
j.
If desired, press the Save button to save this microphone calibration in a file. The use of
the microphone model number and serial number(s) as a filename is suggested.
k.
Press the Generator button again to turn off the generator.
5.
Press Flatten to load a starting point equalization unless another channel was copied to this
one.
6.
Turn the main fader and Gain control (on the left side of the Equalizer tab) all the way
down.
7.
Press the Pink Noise and Generator buttons to turn on pink noise in the auditorium.
8.
Adjust the main fader towards 7.0 without exceeding the desired SPL in the auditorium
(typically 85dB for screen channels and 82dB for surround channels).
9.
Adjust the Equalizer tab Gain control for the desired SPL.
10.
Position the cursor in the RTA graph area to make additional controls visible. Adjust the
Data Offset and X-‐Curve controls to place the mid-‐band RTA levels within the curve limit
lines.
