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4 subwoofer channel – USL JSD-80 Manual User Manual

Page 30

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USL, Inc. JSD-80 Instruction Manual

Page 30

3rd Edition. February, 2006

the generator (e.g., center and subwoofer

channels).
To use the internal JSD-80 REAL TIME

ANALYZER, connect the microphone to

the MIC input on the JSD-80. (See Sec-

tion 12 for connector pin-outs.) With the

pink noise generator turned on and the

equalizer screen displayed on the laptop,

select the inputs screen. Note that the

MIC input is selected. The auditorium

microphone can be adjusted by using the

MIC gain slider. Double click on the REAL

TIME ANALYZER screen. A new window

will open. Slide the window to the bot-

tom of the laptop screen. Now select the

equalizer tab and move the screen above

the REAL TIME ANALYZER display.

2. Slowly raise the level of the left channel

power amplifi er to its full on position.

Now, slowly raise the gain slider until

the SPL Meter indicates approximately

85 dB SPL (82 dB SPL for the surround

channels).

3. Adjust the equalizer sliders until the

response shown is obtained. Please

note that once a slider is selected with

a mouse click, the cursor pad up/down

keys will adjust the slider. The left/right

keys will select the adjacent 1/3 octave

slider. Use the bass and treble sliders

to achieve the overall shape of the

auditorium response. After making the

EQ adjustments, it may be necessary

to fi ne-tune the output level setting.

4. Repeat the tuning procedure for the

center, right and additional channels.

The JSD-80 includes a copy feature that

minimizes the time required for this.

After equalizing the left channel, copy these

settings to the center and right channels.

Since all three front speakers are usually

similar, if not identical, the EQ settings will

be a close starting point. Similarly, after

equalizing the left surround, copy these

settings to the right surround channel.

9.4 Subwoofer Channel

There are three separate subwoofer signals

in the JSD-80. One subwoofer signal is cre-

ated by summing the LT and RT channels

on the two-channel input card. This signal

has its own adjustable low pass fi lter and

+/- 6 dB gain trim. The second subwoofer

signal is a discrete input on the analog eight-

channel connector. The third subwoofer

signal is a discrete input on one of the digital

AES-EBU pairs. All the above signals pass

through the main subwoofer parametric

equalizer and channel gain.

1. Using the Equalizer Screen, select the

Subwoofer channel radio button. Make

sure the gain is set at the minimum,

-22 dB. Slowly raise the power ampli-

fi er gain to maximum. Raise the chan-

nel gain slider on the JSD-80 software

until the Subwoofer signal reaches

roughly the same point as the center

channel on the RTA.