13Setting up the DCA Accessories in the Cinema Sound SystemIf you are unable to obtain a satisfactory frequency response or SPL on a channel, carefully check the wiringand connections. Some likely causes are reversed speaker polarity on one or more drivers, loose or brokenwiring or connections, or blown or damaged speaker drivers.1. Set up the analyzer microphone in the center of the cinema audience seating areaor in another recommended location.2. Set the all DCA amplifiers’ gain controls to maximum.3. Route the pink noise test signal from the cinema processor to the left channel XC-3 input. Observe the frequency response on the spectrum analyzer and use the HFtrim control on the XC-3 and the LF trim on the LF-3 to balance the levels of theirfrequency bands to that of the mid-frequency band, within specifications. If theshape of the HF response is not correct, use a boost setting that better corrects thedeficiency; turn the amplifiers off before changing the switch settings.4. Repeat this process for the center and right screen channels and any surroundchannels that are bi- or tri-amped.5. Follow the processor instructions for setting sound pressure level outputs of all thechannels, including the subwoofer.Setting up the DCA accessories in the B chain of the cinema sound system primarily involves setting the trimlevels on the XC-3, LF-3, and SF-3. This requires the cinema processor’s internal pink noise generator and anacoustical real-time spectrum analyzer.A typical 6.1 surround system with DCA amplifiers and LF-3, SF-3, and XF-3 cinema accessoriesAPPLICATION EXAMPLE- Setting Up in the Cinema Sound System