COMMERCIAL PAGING AND MUSIC SYSTEMS

NBFAA CEU# 96-0344 CARL FOUTZ

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

HOW DOES IT WORK?

INPUTDEVICES

SIGNALPROCESSOR

OUTPUTDEVICES

UNDERSTANDINGSOUND LEVELS

WHAT IS A "dB"?

DECIBEL, A RELATIVE MEASUREMENT FOR SOUND PRESSURE LEVEL (LOUDNESS)

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

DISTANCE EFFECT ON dB

4 FEET 8 FEET 16 FEET

90 dB 84 dB 78 dB

AMPLIFIERS

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)

DISTANCE EFFECT ON dB

4 FEET 8 FEET 16 FEET

90 dB 84 dB 78 dB

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!

CEILING SPEAKER CONSIDERATIONS

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

SPEAKER SPACING-TOP VIEW

1X CEILING HEIGHT

2X CEILING HEIGHT

SPEAKER SPACING-SIDE VIEW

2X CEILING HEIGHT

CEILING HEIGHT

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

SETTING CEILING SPEAKER WATTAGE

BLACK IS COMMON

WATTAGE SET BYCOLORED WIRES

HORN SPEAKER CONSIDERATIONS

PAGING HORN COVERAGE

30 TO 120 FEET(DEPENDING ON AMBIENT NOISE LEVEL)

40 FEET

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.

DISTANCE EFFECT ON dB

4 FEET 8 FEET 16 FEET

90 dB 84 dB 78 dB

STAGGERED PATTERN

ALL HORNS FACING SAME DIRECTION

OPPOSITE PATTERN

HORNS FACING OPPOSITE DIRECTION NO OTHER HORNS FACING INTO THESE

IMPROPER HORN LOCATION

NEVER!CAUSES CANCELLATION AND DECREASED INTELLIGIBILITY!

SETTING HORN/BOX SPEAKER WATTAGE

WATTAGE TAP SET BY ROTATING SWITCH OR SETTING DIPSWITCHES

BOX SPEAKER CONSIDERATIONS

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 SPEAKER COVERAGE

15 TO 60 FEET(DEPENDING ON AMBIENT NOISE LEVEL)

20 FEET

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.

SYSTEM WIRING

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

SPECIALAPPLICATIONS

TELEPHONE PAGING

TELEPHONEKSU

ISOLATION/MATCHINGTRANSFORMER

AMPLIFIER

AMPLIFIER CONNECTED TO PAGING PORT ORUNUSED C.O. LINE ON THE PHONE SYSTEM

SPEAKER

TALKBACK PAGING

TELEPHONEKSU

C.O. LINE PAGING INTERFACE

TALKBACK AMPLIFIER

AMPLIFIER CONNECTED TO UNUSED C.O. LINE ON THE PHONE SYSTEMTALKBACK AMPLIFIER REQUIRED

TALKBACKSPEAKER