Adcom GTP-760 owner manual By Ear, Sound Meter

3.4CHANNEL BALANCE

From the SETUP screen, select CHANNEL BALANCE with the You will see:

>

or >buttons and press select/play.

CHANNEL BALANCE

LEFT	-	+
RIGHT	-	+
CENTER	-	+
REAR L	-	+
REAR R	-	+
SUB	-	+

UNDO CHANGES

DONE

Each piece of home theater equipment operates differently. In the same system, amplifiers may have different gains, speakers may have different efficiencies and, as already discussed, speakers may be positioned in different manners relative to the listener. All of these variables can interact to cause the sound from some of the speakers to be louder than from others. The CHANNEL BALANCE menu allows the volume of each speaker to be individually trimmed so that none of the speakers dominates in playback and detracts from the surround illusion. In essence, the CHANNEL BALANCE screen represents today’s balance control.

The levels in the CHANNEL BALANCE menu may be set in 2 different ways.

By Ear

The first method is intuitive and surprisingly precise. Just as you would with a balance control, play a 5.1 channel movie or music disc. With the CHANNEL BALANCE menu visible, sit in the prime listening position and use the < and > arrow to manipulate each channel level so that all speakers are heard, but no speaker dominates. If you find that one speaker must be compensated excessively, recheck the connections to that speaker. Also, because most subwoofers provide external level controls, it is advised that the subwoofer volume control be manipulated first to match the subwoofer to the system. The GTP-760 CHANNEL BALANCE menu can then be used to fine tune the subwoofer from the listening position. When satisfied with the settings, highlight DONE and press select/play to save your chosen setting and return to the SETUP menu.

Sound Meter

The second method requires the use of a sound level meter (also called a sound pressure meter). The Radio Shack meter, catalog #33-2050, is commonly employed for this task. Turn the meter on, select the C-weighting scale and adjust the range to 70 or 80dB. Place the meter, with microphone pointed upward, at the prime listening position as close as possible to ear level. Press the bal. chk button on the GTP-760 remote. The BALANCE CHECK menu will appear on the screen and the noise sequencer activates. (This menu essentially shows the same information as the CHANNEL BALANCE menu you just saw. Level changes made here are reflected in both menus.) Turn up the GTP-760 master volume control while the noise sequencer circulates around the 5 channels until the needle on the sound meter deflects and rests at a mid-scale position. As the noise sequencer plays through each channel and highlights on the menu, use the < and > remote buttons to adjust the level of that channel to the same needle position on the meter. With a few times through the process, each channel should play back and set the needle to approximately the same meter reading. Press the

bal. chk button again to save the settings and defeat the noise sequencer.

There are 2 things that may be noticed during the channel balance procedure that can cause confusion. First, the master volume knob on the front panel of the GTP-760 sometimes moves when setting an individual channel trim. The master volume knob marks the level of the loudest channel in the system. If when adjusting an individual channel level the knob begins to move, it simply means that the channel being adjusted is now set the highest. THE VOLUME OF THE OTHER CHANNELS DOES NOT CHANGE WHEN THIS HAPPENS.

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