Adcom GTP-740 - Manual (Page 36)

Setting Proper Center Channel Delay
For optimum performance, a single impulse from the front speakers should arrive
at the prime listening position at the same instant. Of course, that requires that
the front speakers are all placed at equal distances from the prime
listening/viewing position (PLP.) This is rarely the case, since the center channel
speaker is usually closer to the PLP than the main left and right speakers. This
would mean that sound from the center speaker would arrive at the PLP before
the impulse from the main left and right speakers and confuse the front
soundfield.
To prevent this from happening, we can delay the center channel signal in the
GTP-740 before it reaches the center channel output. Since sound travels
roughly 1 foot every millisecond (or every thousandth of a second), we can easily
calculate optimum delay by measuring the distance from the main speakers to the
PLP and then comparing that to the distance between the center channel speaker
and the PLP. The difference in these two measurements is the proper delay
setting.
For example, if your main speakers are 15 feet from the PLP and the center
channel speaker is 12 feet, the difference is 3 feet. The corresponding center
channel delay is 3 milliseconds (15-12=3.)
The GTP-740 delays center channel output up to 5 milliseconds and thus
compensates for center channel speakers that are up to 5 feet closer to the PLP
than the main left and right speakers.
In rare system setups, the center channel speaker is actually farther away from
the PLP than the main left and right speakers. In these cases, set the center
channel delay to 0 mS.__________________________________________
Next, adjust rear channel delay time by highlighting REAR with the Up/Down buttons and using < and > to
choose the appropriate setting.
Setting Rear Channel Delay
The principle here is the same. Measure the distance from the rear speakers to
the PLP and compare it to the distance you've already measured from the main
left and right speakers to the PLP. Note the difference and use that as your rear
channel delay setting.
For example, if your rear speakers are 9 feet from the PLP, the correct delay
setting would be 6 milliseconds (15-9=6.)
Again, if the rear speakers are farther away from the PLP than the main
speakers, set delay to 0 mS.________________________
When DELAY settings are completed to your satisfaction, highlight DONE and press Select to return to
the SETUP screen.
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