Dolby Laboratories MPX500 User Manual

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Model MPX500
Microphone Multiplexer
Users' Manual
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Users' Manual
For
Microphone Multiplexer
Dolby Laboratories Incorporated
U.S.A. 100 Potrero Avenue, San Francisco, CA 94103
Tel: 415-558-0200; Fax: 415-863-1373
U.K. Wootton Bassett, Wiltshire SN4 8QJ
Tel: 01793-842100; Fax: 01793-842101
WARRANTY INFORMATION - USA: Warranty on the product covered by this manual is subject to the limitations and disclaimers set forth in the warranty disclaimer originally shipped with the product and also printed on the back of the invoice.
Dolby and the double-D symbol are registered trademarks of Dolby Laboratories Licensing Corporation.
©1996 Dolby Laboratories Inc.
ISSUE 2
S96/10837
Dolby Part No. 91438
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MODEL MPX500
MICROPHONE MULTIPLEXER
Introduction
Intended for use with the Dolby CP500 Digital Cinema Processor, the Dolby Model MPX500 Microphone Multiplexer ensures rapid and accurate theater speaker equalization by enabling the simultaneous use of as many as four microphones (supplied) placed throughout the auditorium.
The MPX500 rapidly switches between the four microphones and sends their outputs to the CP500 over the special 31-meter (100-ft.) Dolby Cat. No. 582 input/output cable (supplied). Digital circuitry within the CP500 then averages the mic outputs for display on its built-in real time analyzer and subsequent EQ adjustments. This eliminates the time-consuming process of moving a single microphone to different locations and manually averaging the results.
Four high-quality electret microphones are supplied with the MPX500 along with 6-meter (20-ft.) connecting cables that adapt the microphones' standard XLR connectors to the “mini-XLR” style input connectors on the MPX500. The Cat. No. 582 input/output cable for connecting the MPX500 to the CP500 contains two individually shielded pairs, one for distribution of bi-directional RS-232 control signals and the other for the multiplexed microphone signal.
A built-in microcontroller chip is programmed to control microphone selection, switching rate between microphones, and the MPX500's LED display. There are no user adjustments on the MPX500 itself.
Unit Set-Up
Position the MPX500 Multiplexer centrally in the listening area and connect the four microphones to it using the four Cat. No. 581 adapter cables. Position the microphones in the room so that they are substantially in the reverberant field rather than receiving mostly direct energy from the speakers. A typical microphone
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placement is shown above. Take care not to place any of the microphones on the central axes of the room, as standing waves and nodes at these positions can cause measurement errors. The microphones should normally be mounted at the listener's head height. However, if the seats have high backs, the microphones should be raised up so that they are at least 23cm (9 inches) above the top of the seat to avoid unwanted effects.
Connect the Cat. No. 582 input/output cable to the MPX500 Multiplexer and secure the hold down screws so that the cable cannot work loose. Route the cable to the location of the CP500 and connect it to the microphone connector on the back panel of the CP500.
The procedure for theater alignment can be found in the CP500 Installation Manual.
Components
Use the listed numbers for ordering replacement parts:
Cat. No. 580 Microphone Multiplexer Unit Cat. No. 581 One Microphone with Adapter Cable
(Part Nos. 51031 and 83294) Part No. 51031 Microphone with 6' (2 meter) cable Part No. 83294 Microphone-to-MPX500 Adapter Cable, 6 meter (20')
Cat. No. 582 MPX500-To-CP500 I/O Cable, 31 meter (100')
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Operation
Display Action
B-Chain Alignment
key
Allignment
key
Format
Selection
Menu
key
Menu
Selection
press:
System
Alignment
screen shows:
screen shows:
press:
press:
screen shows:
Mic Mux
key
B-Chain
Alignment
screen shows:
press:
FORMATS
Menu
Cancel OK
Exit
SK8
OK
To select one mic:
SK1 - SK4
To remove one mic:
SK1 - SK4
SK5
To resume scan:
SK8
Begin by entering the microphone multiplexer control screen on the CP500:
Press the Menu key
Press ALIGNMENT (SK2)
(A system password may be required at this point)
Press the B-chain Alignment key (SK1)
Press the Mic Mux key (SK3)
Note:
While performing equalization, this multiplexer control screen may be entered directly by pressing soft key 5 (
SK5
).
To scan through the microphones press the Scan key (SK8).
The scan rate may be set by pressing the Set scan rate key (SK6). Rotate the front panel knob until the desired rate is displayed then press OK. The number displayed is the time spent connected to each microphone.
Pressing any soft key SK1 through SK4 will halt scanning and enable the corresponding microphone.
To remove a microphone from the scan sequence, select the microphone by pressing the corresponding softkey, then press the Enable/Disable key (SK5).
Resume scanning by pressing the Scan key (SK8)
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