Adcom GTP-740 - Manual (Page 39)

When you’re satisfied with the relative levels, scroll to DONE and press Select. This will commit the
changes to memory and exit to the SETUP screen.
NOTE: Although this screen allows individual channel adjustments, it is not ideal
for initial calibration. If you’re using the GTP-740 for the first time, we suggest you use
the remote controller’s bal. chk button to begin the initial calibration. The reason for this
is that the bal. chk procedure turns on the GTP-740’s internal test tone generator and
automatically steps that test tone through all six outputs.
3.7 Using bal. chk
The remote controller’s bal. chk button is the easiest way to calibrate the GTP-740. Once your system is
connected and functioning, press the bal. chk button. You will see the following screen:
BALANCE CHECK
LEFT +
CENTER - +
RIGHT +
REARR - +
REARL - +
SUB +
UNDO CHANGES
DONE
You will hear a Vaterfall” test tone advancing from speaker to speaker. You will also see the highlight bar
automatically advandng through LEFT, CENTER, RIGHT, etc., in synchronization with the test tone.
Before making any adjustments, place your sound level meter as closely as possible to ear height at your
favorite listening/viewing position. (Most sound level meters have a threaded connection on the bottom for
a camcorder or camera tripod that may help you do this.) The meter should be “free standing;" avoid
putting it close to reflective surfaces (including your own body) as reflected sound waves will reduce
reading accuracy.
When using a sound level meter, set it to "Slow" response (to better average
continuous readings), "C" weighing (the *C" scale is more accurate for the type of
measurement you need to do), and adjust the "range" setting to 80 dB._________________
Adjust the GTP-740’s master volume control until the sound level meter registers approximately 80 dB as
the test tone cycles through the channels. (Don’t be concerned about variations here—once you’re done
calibrating, they won’t be there any longerl)
Wait until the test tone cycles to the LEFT speaker and verify that you’ve got an 80 dB reading. (If not,
use the master volume control to increase and decrease the test tone volume as necessary.) When the
test tone cycles to the CENTER speaker, use the remote controller’s < and > arrow buttons to adjust
center channel level until you get an 80 dB reading. (You will notice that the test tone will not cycle to the
RIGHT speaker until you’ve completed adjusting the CENTER output.) Repeat this procedure for every
channel.
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