Specifications

5-2
B-Chain Alignment
•
Blown fuses.
•
Good air movement through power amplifiers.
Air-conditioning
If air-conditioning noise is audible in the theater, arrange for lubrication of the
motor and fan bearings, adjustment of belts and drives, and cleaning of filters to
reduce the ambient noise to a minimum.
5.2 Preparing for Room Equalization
Using a Microphone Multiplexer with the CP500
If you are using a Dolby Cat. No. 580 Microphone Multiplexer system and need
instructions on its use, turn to
Section 9.2
.
5.2.1 Configure the Cat. No. 682 for use with the
Optional Cat. No. 683 Electronic Crossover Card
Verify that the Cat. No. 682 jumpers J901, J3, J4, and J5 are set to the "YES"
position to enable the crossover features of the Cat. No. 683.
5.2.2 Screen Channels
The factory setting for the Cat. No. 683 card has the Low Frequency Time Delay
Enable Jumpers set to DELAY. This indicates that jumpers J100, J200, and J300 of
the Cat. No. 683 card allow the low frequency portion of the designated channels to
be delayed by 1.9 ms or 0.8 ms. The “DELAY” setting compensates for the time
offset caused by high frequency drivers being behind the low frequency drivers in
contemporary stage speakers. Sound produced by the low frequency speakers is
delayed to cause the low and high frequency energy to reach the listener at the same
time. There is no low frequency delay when the jumper is set to “NO DELAY”.
Board locations RN102, RN202, RN302, and RN600 select the desired crossover
frequency and locations RN101, RN201, and RN301 select the time delay. For
large horns, the correct setting is usually 500 Hz and 1.9 ms. For small horns, 800
Hz and 0.8 ms is usually correct. Check the loudspeaker manufacturer’s
specifications for details.