Dolby Laboratories CP650 Installation Manual download pdf (Page 54)

Dolby

Model CP650 Installation Manual B-Chain Alignment

4-2

• Ensure that there is good air movement through power amplifiers.

Air-Conditioning

If air-conditioning noise is audible in the theatre, 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.

4.2 Microphone Placement

Position a microphone multiplexer in the center of the listening area. Place each

microphone in the auditorium so that each is substantially in the reverberant field

rather than in an area that receives the most direct energy from the speakers. In

addition, avoid perfect symmetry. Arrange the microphones so that they are not

arranged in a perfect square or rectangle parallel to the sides of the room. Take care

not to place any of the microphones (except mic number 1) on the central axis of the

room. Standing waves and nodes at these positions can cause measurement errors.

Microphone number 1 should be placed two-thirds of the distance from the front

speakers to the rear, at the exact side-to-side center of the room, approximately five

feet above the floor level, and rotated 45 degrees upward towards the screen.

Placement of this microphone is important for output level adjustments.

Figure 4–1 EQ Microphone Placement

If a single microphone is used (NOT advised), the recommended position would be

two-thirds of the way from the front speakers to the rear, off the axis of the center

speaker, five feet above the floor level, and rotated 45 degrees upward towards the

screen.

Route the output cable to the CP650 and connect it to the microphone connector on

the rear panel or front setup panel (XLR on the rear panel or nine-pin D-connector

“MIC MUX” input on front setup panel). The mic input connectors are wired in

parallel. Phantom power is optionally provided to both mic connectors by moving

DIP switch 3 to the up position.

1.5 meters

(5 feet)

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Dolby Laboratories CP650 Installation Manual Page 54