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PURPOSE OF SOUND SYSTEM
ALLOWS AUDIO SIGNAL TO BE REPRODUCED AT HIGHER LEVEL FOR DISTRIBUTION INTO OTHER AREAS.
TYPES OF SYSTEMS
PAGING– ALERT OR NOTIFICATION
BACKGROUND MUSIC– LOW LEVEL AUDIO FOR "ATMOSPHERE"
FOREGROUND MUSIC– HIGH LEVEL AUDIO FOR "ENTERTAINMENT"
HOW DOES IT WORK?
INPUT DEVICES (MICROPHONE, MUSIC SOURCE) SEND LOW LEVEL SIGNAL TO SIGNAL PROCESSOR
SIGNAL IS PROCESSED (AMPLIFIED, EQUALIZED, MIXED) AND SENT TO OUTPUT DEVICES
OUTPUT DEVICES DISTRIBUTE SIGNAL TO OTHER AREAS AT HIGHER LEVEL
TYPICAL dB LEVELS
0 dB140 dB(THRESHOLD OF HEARING)
(THRESHOLD OF PAIN)
10 dB 20 dB 40 dB 60 dB 80 dB 100 dB 120 dB
WHISPER CONVERSATION
QUIET OFFICE
SUPERMARKET
DIESEL TRUCK @ 50'
CONSTRUCTION SITE
NOISY OFFICE
RESTAURANT
dB AND DISTANCE
EACH TIME DISTANCE FROM SPEAKER IS DOUBLED THE dB LEVEL IS REDUCED BY 3/4X (75%)LOSS OF 6dB OF POWER
EACH TIME DISTANCE FROM SPEAKER IS HALVED THE dB LEVEL IS INCREASED BY 4X GAIN OF 6dB OF POWER
OHMS VS. WATTS
OHMS– SPEAKERS RATED BY OHM LOAD – SPEAKERS MUST BE BALANCED TO KEEP SYSTEM
OHM LOAD CORRECT
WATTS– SPEAKERS ARE RATED BY WATTAGE – IS TOTALED TO DETERMINE AMPLIFIER LOAD– BALANCING LOAD NOT REQUIRED
25V OR 70V SPEAKER LINES?
COMMERCIAL PAGING/MUSIC SPEAKERS RUN ON 25V OR 70V SPEAKER CIRCUITS
– 70V CAN RUN 8 TIMES THE DISTANCE OF 25V ON THE SAME GAUGE WIRE
25 VOLT WIRING DISTANCES
WIREGAUGE
TOTAL WATTAGE1W
1000
5000
8000
22 AWG
18 AWG
16 AWG
5W
300
1000
1800
10W
200
500
800
25W
70
300
200
50W
40
100
150
100W
15
50
70
70 VOLT WIRING DISTANCES
WIREGAUGE
TOTAL WATTAGE1W
10000
12000
14000
22 AWG
18 AWG
16 AWG
5W
3000
7000
12000
10W
2000
5000
7000
25W
600
1800
2500
50W
400
800
2500
100W
150
400
700
SPEAKER WIRING
RUN IN PARALLEL
T-TAPPING IS PERMITTED
KEEP BLACK (COMMON) AND WATTAGE TAP (COLORED) WIRE ON SAME CONDUCTOR THROUGHOUT
SUGGESTED SPEAKER LOAD ALLOWANCES
AMBIENT NOISE LEVEL CEILING HORN/BOX
QUIET (50-70dB) 1/2 TO 1 WATT 1 TO 5 WATT NOISY (74-85dB) 1 TO 2 WATT 5 TO 10 WATT
VERY NOISY (86-96dB) 2 TO 4 WATT 10 TO 15 WATT
RELATIONSHIP BETWEEN AMP POWER & SOUND PRESSURE
2 WATTS = + 3DB 4 WATTS = + 6DB 10WATTS= +10DB (TWICE AS LOUD AS 1 WATT) 20WATTS = +13DB 40WATTS = +16DB 100WATTS= +20DB (FOUR TIMES AS LOUD AS 1 WATT)
200WATTS= +23DB 400WATTS= +26DB 1000WATTS=+30DB (EIGHT TIMES AS LOUD AS 1 WATT)
AMPLIFIER SELECTION CONSIDERATIONS
WATTAGE REQUIRED?– SPEAKER LOAD
INPUTS REQUIRED?– MICROPHONE, MUSIC, TELEPHONE
SPECIAL FEATURES– EQUALIZER, TALKBACK, ZONING
MAXIMUM SOUND, MINIMUM SMOKE
ALWAYS SIZE THE AMPLIFIER TO THE SPEAKER LOAD, NOT THE SPEAKER LOAD TO THE AMPLIFIER!
SPEAKER PLACEMENT CONSIDERATIONS
AMBIENT (BACKGROUND) NOISE LEVEL
DISTANCE TO TARGET AREA
APPLICATION– PAGING OR BACKGROUND MUSIC
CEILING SPEAKER SPACING
CEILING SPEAKERS SHOULD BE SPACED AT TWO TIMES (2X) THE CEILING HEIGHT
– SPEAKER SPACING == CEILING HEIGHT X 2
SPACED EQUAL TO CEILING HEIGHT (1X) FROM WALLS
ON CEILING SPEAKERS...
BACKGROUND LEVEL MUSIC/NORMAL PAGING– NORMAL CEILING SPEAKER SPACING (2X)
FOREGROUND LEVEL MUSIC/NOISY AREA PAGING– HALF NORMAL SPACING (1X)– TWICE AS MANY SPEAKERS REQUIRED
SPEAKER MOUNTING
PLENUM CEILING– MAY REQUIRE PLENUM CABLE OR CONDUIT
BACK BOXES– MAY BE REQUIRED ON PLENUM OR PLASTER
CEILING
TILE SUPPORT– RECOMMENDED ON DROP CEILINGS
HORN FORWARD PROJECTION
AMBIENT SQUARE FT.NOISE LEVEL PROJECTION COVERAGE
QUIET (50-70dB) 120 FEET 5000 S.F. NOISY (74-85dB) 60 FEET 2500 S.F.
VERY NOISY (86-96dB) 30 FEET 1250 S.F.
WHEN TO USE BOX SPEAKERS?
MUSIC ONLY OR PAGING WITH MUSIC APPLICATIONS
PROVIDES BETTER QUALITY SOUND FOR MUSIC THAN HORNS
ONLY HALF THE COVERAGE OF HORNS
BOX FORWARD PROJECTION
AMBIENT SQUARE FT.NOISE LEVEL PROJECTION COVERAGE
QUIET (50-70dB) 60 FEET 2500 S.F. NOISY (74-85dB) 30 FEET 1250 S.F.
VERY NOISY (86-96dB) 15 FEET 625 S.F.
PAGING AND MUSIC SOURCE WIRING
MICROPHONES– INDIVIDUALLY HOME RUN TO AMPLIFIER– 2C OR 4C (PREFERRED) SHIELDED CABLE
MUSIC SOURCES– INDIVIDUALLY HOME RUN TO AMPLIFIER– 2C SHIELDED CABLE
WIRING
AMPLIFIER
MICROPHONE
BLACK (COMMON)
WATTAGE TAP(COLORED)
2C OR 4CSHIELDED
MUSICSOURCE
2C SHIELDED
SPEAKER ZONE PAGING
SPEAKER
SPEAKER AMPLIFIER
ZONE PAGING MODULE
PAGING INTO DIFFERENT AREAS (ZONES) BY SWITCHING AMPLIFIER OUTPUT TO DIFFERENT SPEAKERS
AMPLIFIER ZONE PAGING
AMPLIFIER #2
SPEAKER
SPEAKER
AMPLIFIER #1
ZONE PAGING MODULE
PAGING INTO DIFFERENT AREAS (ZONES) BY SWITCHING MIC OUTPUT TO DIFFERENT AMPLIFIERS
TELEPHONE PAGING
TELEPHONEKSU
ISOLATION/MATCHINGTRANSFORMER
AMPLIFIER
AMPLIFIER CONNECTED TO PAGING PORT ORUNUSED C.O. LINE ON THE PHONE SYSTEM
SPEAKER
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