www.bogen.com
64
SYSTEM DESIGN GUIDE
70V Paging Systems consist of:
• A Centralized Amplifier which offers a variety of features
to enhance voice and music reproduction as well as easy system
expansion.
• Speakers that connect with a simple 2-wire installation because
the audio power is supplied from the centralized amplifier.
• An Interface Device that connects the paging system to the
telephone system. (Depending on the telephone system and
amplifier, an interface device may not be needed.)
The aim of a paging system is to deliver important audio announcements to people working in a facility at the proper level and with
sufficient clarity to make the announcement easily understood.
The two most common ways to accomplish this is to use either
70V centralized amplifiers with passive speakers or self-amplified
speakers operating from a 24V DC power supply.
Pages 64-67 explain 70V systems and pages 68-69 explain selfamplified systems. Speaker layout, wiring methods, and phasing are
the same for either technology and are covered on pages 70-73.
What Is A 70V System?
Low Currents Allow Long Runs
Why do distributed sound systems use centralized amplifiers with 70V
output signals? Because 70V systems can handle extremely long
lengths of wire to connect the speakers to the amplifier,
and they can power a large number of speakers in each system.
When sending power signals over long distances, it is important to
minimize the amount of current flowing in the wire. High currents
allow too much power, or electrical energy, to be wasted in wires in
the form of heat.
The power (P) lost in the wire is related to the square of the current
(
I
), so reducing the current in the wires a little reduces the power
lost in them considerably. In fact, reducing the current flowing in a
wire by a factor of 2 will reduce the power loss by a factor of 4.
However, the power the load demands and the output level of the
amplifier determines the amount of current that must flow in the
speaker wires (Ohms' law in action).
So to lower the amount of power lost in the wires, the voltage that
the amplifier uses to drive the load is increased. By doing this, the
current in the wires can be reduced while still supplying the same
power to the load (for the same power P, any increase in V will lower
I
).
Of course you cannot just change the voltage driving a load from one
level to another without also making the load compatible with the
new voltage level.To ensure compatibility, 70V systems use transformers on the speakers that change the high 70V amplifier output levels
to lower levels that are compatible with typical 8-ohm speakers.
Easy To Control Speaker Power Draw
The output of a central paging amplifier is designed to limit the
maximum output voltage that can be supplied to the speakers.
This maximum output voltage remains the same regardless of the
amplifier’s power capacity. Because the output voltage is limited,
speaker manufacturers can design products that consume a specific
amount of power from the amplifier.This is beneficial in two ways.
First, the speakers will not consume more power than they are
designed for; so, they cannot blow out from using an amplifier that’s
too powerful. Second, since each speaker’s power consumption is
known, the correct amplifier power for the paging system is simply
the total power drawn by all the speakers.
BGM
IN
PAGING TIMEVOX DELAYTONE VOL.
MIN MAXMIN MAXMIN MAX
TAM B
TELEPHONE ACCESS MODULE
BOGEN
RAMSEY, N.J.
COMMUNICATIONS
S5
S5
VOX ENABLE
VOX DISABLE
S3
S4
PREANNOUNCE TONE
S3 S4
CONFIRMATION TONE
48VDC PWR SUPPLY S1,S2
24VDC PWR SUPPLY S1,S2
ONOFFMODE
RINGER EQUIVALENCE: 1.2 B
CD23CH-17705-KX-N
FCC REGISTRATION NUMBER:
COMPLIES WITH PART 68, FCC RULES
VOL
BGM
SWITCHES
MODE
(0.1A)
(TRUNK ACCESS ONLY)
POWER SUPPLY
CONTACT CLOSURE A
PAGING OUTPUT
EXT VOX ENABLE
PHONE SYSTEM
-24/48
+24/48
COM
N.O.
PR
PT
-M
+M
R
T
PEAK LEVEL
POWER
BOGEN
MODEL TPU AMPLIFIER
ALC
TEL VOLUME
MIC VOLUME
MUSIC VOLUME
MUSIC MUTE
RINGER VOLUME
VOX SENS
BASS
TREBLE
APHEX
TAM B
CENTRALIZED AMPLIFIER
TPU 100
SPEAKER
S86T725
Why Use 70V Outputs?
Paging System Technology
Central-Amplified Systems - pages 64-67
Self-Amplified Systems - pages 68-69
Power Lost
In Wires
(Watts)
Resistance
of Wire
(Ohms)
Current Flowing
In Wire
(Amps)
P = I
2
*
R
Current Flowing
In Wire
(Amps)
Amplifier
Output Voltage
(Volts)
Power Needed
By Load
(Watts)
I = P / V
www.bogen.com
65
SYSTEM DESIGN GUIDE
70V Output
A 70V output is available on Bogen amplifiers and is the primary
type of output for paging systems.A step-up output transformer in
the amplifier provides the high 70V output signal.All speakers with
step-down transformers (rated for 70V systems) are connected to
this output.
Other Output Types
(25V, 16- and 8-ohm)
There are a number of other standard speaker impedances that
Bogen amplifiers can be connected to.These outputs provide the
correct speaker signal levels for different configurations of low impedance speakers.The lower voltage, 25V, output is provided on many
Bogen amplifiers for use in paging installations that require a speaker
voltage of less than 70V to meet building code requirements.
Direct Output
Direct outputs are used with low impedance speakers.These outputs
have an exceptional low frequency (bass) response, providing the
fuller sound that low impedance speakers can reproduce. Certain
Bogen amplifiers, designed for general purpose sound reinforcement
applications, include this feature which allows the step-up output
transformer to be bypassed for direct connection to the power
amplifier’s output.
What Makes A 70V Speaker?
Amplifier Output Types
Step-Down Transformer
70V paging speakers have a step-down transformer, which is used
to convert the high-voltage/low-current amplifier signal of the
central paging amplifier to the low-voltage/high-current signal that
speakers use.
Taps
The primary side of the step-down transformer (the side that
connects to the amplifier) has a number of connections (called
taps or power taps) that can be used to select the peak power
the speaker will consume from the amplifier.
Why Taps?
The selection of the power tap has an effect on both the amplifier
power needed for the system and the volume of the speaker.The
more power a speaker consumes, the louder the sound from the
speaker. By tapping speakers for lower power in quiet areas and
for higher power in noisier areas, the sound level of the paging
system can be controlled and balanced.
It is important that speakers be tapped correctly for the area that
they will be used in. Setting all the speakers for the same power
regardless of the amount of noise in different areas will cause
balance problems. If the amplifier is adjusted to produce adequate
paging levels in the noisy areas, the paging levels in the quiet areas will
be too loud or vice versa. Selecting the proper tap setting is not difficult, but it does require knowing the level of ambient noise in different areas. (See Sound Pressure Levels Chart on page 77.) It is always
better to use the next higher wattage tap if there is any doubt about
the speaker being sufficiently loud for the area.
Of course, the best way to determine how effectively a system covers
an area is to test it. Never install a paging system and leave the site
without testing it. Sound adjustments or additional speakers may be
needed. Some paging equipment, such as Bogen’s PCM2000, UTI1,and
UTI312 paging interfaces include a test tone that is sent to all speakers in the system so installers can check the system installation. For
other systems, the installer can have pages made while the installer
walks the area to listen for appropriate sound levels and uniform coverage of the system to find out if and where adjustments need to be
made, and to make sure that all speakers are properly connected.
Easy Design™Without Taps
To make designing paging systems as easy as possible, Bogen offers
a line of Easy Design
™
speakers.These speakers do not require tapping and allow for on-the-fly adjustment of speaker paging levels.All the
information that is needed to design a complete system are the
dimensions of the different paging areas and the type of environment.
With this basic information, you can use the Easy Design speaker line
to quickly design a robust, professional, and powerful paging system.
(See pages 3-9 for more information.)
U
LINK DIRECT
OUT 4
70V8
U
25V
16
GND COM
U
www.bogen.com
66
SYSTEM DESIGN GUIDE
Amplifier Input Types
Auxiliary Input (AUX)
The Auxiliary input is the most common type of input used in
paging.This input is designed to connect to most music sources,
such as a CD player or tuner. Usually the connector for such an
input is a Phono jack (also called an RCA jack). It connects to
other equipment using standard audio cables.
The AUX input has an outer connection that is directly connected
to the equipment’s ground and a center connection that is the
“hot” input. AUX inputs, sometimes referred to as Hi-Z or high
impedance inputs, have a high input impedance so that they won’t
put too much of a load on the source equipment’s output.This type
of input is “unbalanced”.You must use shielded cable with this type
of input in order to avoid getting noise induced into the system.
Normally, connections between source equipment and the amplifier’s
AUX input should not be too long, about 6 feet.The problem with
long connections is that the cable acts like an antenna, picking up
any electrical noise in the area.The longer the cable, the more
noise that is picked up.
Telephone Input (TEL)
The TEL Input is so named because it was designed to be compatible
with page port outputs of telephone systems.The TEL input is a
600-ohm transformer-coupled input that:
• matches the impedance of the telephone port to provide
proper interfacing
• electrically isolates the amplifier from the PBX or Key System
• provides a balanced input with a great deal of noise immunity
Bogen’s TEL inputs do not have to be shielded, but it is always a good
idea to provide more noise immunity (normally a ground terminal is
available on the input for the shield connection). Higher noise
immunity allows the amplifier to be located much farther away from
the source equipment than what an unbalanced input will allow.
The input transformer is not designed to pass loop current from a
telephone line.Any time you want to connect to a telephone station
or trunk port, you will need to use a telephone interface module
like the TAMB, which converts the telephone signal into a “dry”
audio signal compatible with the amplifier’s TEL input.
Microphone Input (MIC)
The traditional paging amplifier input is the Microphone input. MIC
inputs were the primary announcement source until connection to
the telephone system became possible. MIC inputs are still used in
public address applications today.
When connected properly, a microphone can be hundreds of feet
away from the amplifier and still provide clear, quiet audio.
MIC inputs are the most sensitive of all the amplifier inputs and
tend to pick up the stray electrical noise in an area.To combat
the noise pickup problem, MIC inputs are balanced. Just like TEL
inputs, the balancing of the input provides a high level of noise
immunity. MIC inputs are also made to have a fairly low input
impedance, which makes it difficult for electrical noise to get
induced.The low impedance effectively keeps down noise, which
makes its signal level smaller.
Microphone cable is always shielded.The input requires three connections – two for the balanced signal and one for the shield ground.
You can reverse the balanced signal leads and the system will still
work properly. However, if you mis-wire the ground connections, the
amplifier can become unstable and start to oscillate. When this
occurs, the amplifier may heat up enough to cause its protection
circuits to shut it down or it may produce very distorted sound.
Phono (RCA) Input Jacks
Telephone Input Screw Terminals
Balanced Microphone “XLR” Type Connector
Balanced Microphone Screw Terminals
- see page 81
www.bogen.com
67
SYSTEM DESIGN GUIDE
Designing 70V Systems
# of
Speakers
Speaker
Coverage
Total Area
(Sq. ft.)
÷
=
CEILING SPEAKERS
Models CSD1X2, SM4T, S86/S810T725PG8W
and variations.
To determine the number of ceiling speakers your
installation requires, simply divide the area’s total
square footage by the speaker coverage as
indicated in this chart.
HORN LOUDSPEAKERS
Models SPT5A/15A/30A.
To determine the number of horn loudspeakers
your installation requires, simply divide the area’s
total square footage by the speaker coverage as
indicated in the chart below.
To determine tap settings, use
the appropriate chart.
WALL BAFFLE SPEAKERS
Models WBS8/S810T725 & variations.
To determine the number of wall baffle speakers
your installation requires, simply divide the
area’s total square footage by 600 square feet.
Coverage is 600 sq. ft. per speaker
See chart below
Total
Speakers
Minimum
Amplifier Power
Ta p
Wattage
X
=
Ceiling
Height (ft.)
Coverage
(sq. ft.)
8 250
10 400
12 580
14 780
# of
Speakers
600
Sq. ft.
Total Area
(Sq. ft.)
÷
=
Ambient
Noise Range
Ceiling Height (ft.)
8101214
Low Noise
(55 dB-65 dB)
Medium Noise
(65 dB-75 dB)
High Noise
(75 dB-85 dB)
Very High Noise
(85 dB-95 dB)
*
SM4T Tap Settings +S86/S810 Tap Settings
1/2W*1/2W
*
1W 1W
1/4W+1/4W
+
1W*1W
*
2W 4W
1/2W
+
1/2W
+
4W
Ambient
Noise Range
Tap Setting
Low Noise
(55 dB-65 dB)
Medium Noise
(65 dB-75 dB)
High Noise
(75 dB-85 dB)
Very High Noise
(85 dB-95 dB)
1W
4W
Recommended
Wall Baffle Tap Settings
Recommended Horn Tap Settings
Amplifier Selection
Once you know the minimum amplifier power your system
requires, refer to the Amplifier Charts on pages 78-79.
Recommended
Ceiling Speaker Tap Settings
# of
Speakers
Speaker
Coverage
Total Area
(Sq. ft.)
÷
=
Figuring out how many speakers you need for your application is simple.You only need the dimensions of
the area in which the paging system will be installed.
• For Bogen’s Easy Design™line speakers, refer to the charts on pages 6-8.
• For speakers with multiple tap settings, refer to this section for information.
1
Determining
Quantities
2
Determining
Taps
To determine the total power your installation will require, simply multiply the
number of speakers by the tap wattage.
3
Determining
Amplifier Power
See page 75 for
Wire Loss
Information
Ambient
Noise Range
Low Noise
(55 dB-65 dB)
Medium Noise
SPT5ASPT15ASPT30A
(65 dB-75 dB)
Medium Noise
(65 dB-75 dB)
High Noise
(75 dB-85 dB)
Very High Noise
(85 dB-95 dB)
High Noise
(75 dB-85 dB)
Very High Noise
(85 dB-95 dB)
Speaker
Power Taps
(Watts)
1.25W 6,500
7.5W 6,500
.9W 7,000
3.8W 6,500
15W 2,500
3.8W 7,000
30W 5,500
Coverage
(sq. ft.)
www.bogen.com
68
SYSTEM DESIGN GUIDE
Self-Amplified Paging Systems consist of:
• Self-Amplified Speakers each contain an individual, built-in,
miniature amplifier that drives the speaker directly. Each speaker
requires 4 wires.Two wires supply the raw 24V DC voltage to
power the speaker’s internal amplifier and another 2 wires
supply the low level audio paging signal to the amplifier’s input.
All amplified speakers contain volume controls to adjust
output level.
• A Power Supply or multiple power supplies which supply the
raw 24V DC voltage that will power the amplifier built in to each
self-amplified speaker. Several power supplies can be located in
convenient areas in the facility.
• An Interface Device that connects the paging system to back-
ground music sources and the telephone system and supplies a
telephone level audio paging signal to all the speakers in the system.
(Depending on the telephone system and number of speakers in
the system, an interface device may not be needed.)
What Is A Self-Amplified System?
A self-amplified system can be expanded by adding extra speakers and
power supplies as required.They are extremely scalable due to the
fact that each speaker is an amplifier unto itself. It is also easy to
connect additional power supplies where needed to power the
speakers. In some instances there may not be sufficient audio signal
level available for the speaker’s input. In these instances a small buffer
can be installed inline to boost the signal level.
Self-amplified speakers can also be used to expand 70V paging systems
in cases where the added speakers would overload an existing central
70V amplifier. The same buffer that is used to boost signal level can be
used to reduce the large 70V speaker signal to a level that is compatible with the input of self-amplified speakers. A suitable power supply
can be located near the expansion speakers to power their internal
amplifiers.This approach can be used instead of replacing the central
70V amplifier with a larger one to handle the extra speakers.
Convenient System Expansion
Self-Amplified paging systems are made up of equipment that
consume or provide operating current.To operate properly,
the system needs to provide at least as much 24V current as
it consumes.
Each product has a Current Units number.This number is
either positive, negative, or zero to indicate how much current
it provides or consumes from the system.
Note: One Current Unit = 50 mA, 24V DC
Understanding Current Units
Low Signal Levels Prevent Crosstalk
In certain installations it may be desirable to use conductors in an
existing telecommunication cable to deliver paging to different floors
or areas in a facility. 70V amplifier signals would not be appropriate to
run in the same cable with analog telephone signals since their high
level could cause crosstalk in the other telephone circuits in the
cable. Because the audio signal levels supplied to the inputs of the
amplified speakers are similar in level to analog telephone levels, there
will be no crosstalk of the paging system in the telephone lines.
The raw 24V DC power needed by the self-amplified speaker can
also be carried in the telecom cable since it contains no interfering
signals, but care must be exercised to make sure the length of cable
will not cause too much voltage to be lost in the cable.
Why Use Self-Amplified Technology?
Self-amplified speakers can be very cost effective in small systems
since they provide scalability in small increments.The centralized
amplifiers in 70V systems are typically available in set output power
levels steps that start at 6 or 10 watts and increment by 10 watts or
more from model to next higher powered model. In small applications that require only a few watts of paging, the extra power capability of the 70V amplifiers may not be an advantage due to the higher
cost associated with the amplifier’s extra power, especially if it will
not be used in the future.
Self-amplified systems can be designed with much smaller output level
power steps so that only the necessary audio power is installed in
the facility. This can result in a lower cost of equipment especially
where the desired power level is considerably less than the smallest
applicable 70V amplifier output level.
Cost Effective for Small Installations
Provides
System Current
Consumes
System Current
No Draw
on the System
AUDIO
DC POWER
www.bogen.com
69
SYSTEM DESIGN GUIDE
What Makes A Self-Amplified Speaker?
Built-In Amplifier
As the name suggests, all self-amplified speakers contain their own
miniature amplifier.These amplifiers range in size from 1 watt, which
are used on cone speakers, up to 15 watts, which are used on the
SAH15 and AH15A horn speakers.
Bogen’s latest line of self-amplified horns use a revolutionary digital
switching amplifier. Unlike conventional analog amplifiers, this
advanced technology produces very little heat when it operates.
It produces so little heat that all it needs to dissipate the waste heat
are the copper interconnecting traces on the printed circuit board
instead of the typical large aluminum heatsinks. Because it produces
so little heat it also draws considerably less power from the power
supply. Why? Because it is not wasting half of the power supply energy
it consumes as heat.
More typical in the industry are speakers that employ analog amplifiers,
which produce considerable waste heat while operating.They typically
release half the 24V power they consume in the form of heat, and
heat is a major contributor to the failure of an amplifier.
The amplifiers in Bogen’s AH series of self-amplified horns are analog
but rid themselves of waste heat through their large cast aluminum
end bell that works as an excellent heat sink, quickly and effectively
removing excess heat. Competitve products using plastic end bells
don’t have this cooling advantage.
4 Wires
All self-amplified speakers require 4 wires to make the necessary connections.Two of the connections are used to provide 24V DC power
to the built-in amplifier. The other connection pair to a self-amplified
speaker is for the audio signal input.
The general audio signal level is the same as what you would find on any
analog telephone line.The input is transformer balanced, also similar to
the inputs found on telephone systems.The balanced nature of the input
greatly reduces interference and noise caused by equipment running in
the facility
.The use of an actual transformer provides electrical isolation
between
the input leads and the actual amplifier, which protects it from
ground loops and RF interference, and provides an all-around rugged input.
Designing Self-Amplified Systems
# of
Speakers
Speaker
Coverage
Total Area
(Sq. ft.)
÷
=
CEILING SPEAKERS
Models ACD2X2,ASWG1,ASWG1DK.
To determine the number of ceiling speakers your
installation requires, simply divide the area’s total
square footage by the speaker coverage as
indicated in this chart.
HORN LOUDSPEAKERS
Models AH5A, SAH5,AH15A, and SAH15
To determine the number of horn loudspeakers
your installation requires, simply divide the area’s
total square footage by the speaker coverage for
the noise level in the area as indicated in the
chart below.
WALL BAFFLE SPEAKERS
Model ASWB1
To determine the number of wall baffle speakers
your installation requires, simply divide the
area’s total square footage by 600 square feet.
Ceiling
Height (ft.)
Coverage
(sq. ft.)
8 250
10 400
12 580
14 780
# of
Speakers
600
Sq. ft.
Total Area
(Sq. ft.)
÷
=
SAH5A, AH5A
Low Noise
(55 dB-65 dB)
Medium Noise
(65 dB-75 dB)
(75 dB-85 dB)
High Noise
(75 dB-85 dB)
Very High Noise
(85 dB-95 dB)
8050 LOW
HIGH
LOW
MEDIUM
HIGH
Coverage
Volume Setting
Ambient
Noise Range
Medium Noise
SAH15A, AH15A
6955
6955
6500
2600
# of
Speakers
Speaker
Coverage
Total Area
(Sq. ft.)
÷
=
Figuring out how many speakers you need for your application is simple.
• For Bogen’s Ceiling and Wall Baffle Speakers, you will need room dimensions.
• For Bogen’s Horn Speakers, you will need room dimensions and ambient noise levels.
1
Determining
Quantities
2
Determining
Power Supply Capacity
To determine total 24V DC Power Supply
size requirement use the equation below.
1. Add all the numbers of the Self-Amplified speakers and volume controls together.
2. Select a Power Supply (or power supplies) with a number(s) equal to or greater than the total amount.
For more information on see pages 21 and 68.
See page 28 for
Power Supply
Selection.
See page 75 for
Maximum
Wire Lengths
Coverage is 600 sq. ft. per speaker
www.bogen.com
70
SYSTEM DESIGN GUIDE
Speaker Layout
Horn Loudspeakers
Desired mounting height, barring obstructions, is 15 to 20 feet,
with the speakers angled downward toward the listening area and
facing in the same direction. Follow the diagram for the layout of
the horn speakers while using the charts below to define the lettered dimensions for each specific speaker.
Begin in one corner of the area.The first speaker in Row 1 is positioned a distance equivalent to (1/2C).The next speaker in Row 1
should be a distance equivalent to (C) from the first speaker. Each
additional speaker in the row should use this same spacing. Row 2
starts at the indicated distance (D) from the wall. Using the diagram
as a guide, fill in the remaining rows in this same alternating
pattern until the entire area is appropriately covered.
For areas that include high shelving or corridors, speakers should
be installed so that they project down the aisles between the
shelves or down through the corridors.
The spacing of the speakers can be adjusted so that the speakers
are evenly spaced in a row.
Ceiling Speakers
Layout starts in one corner of the area.The first speaker should
be positioned from each wall a distance approximately equal to
the ceiling height of the room (dimension A).
The next speaker in row 1 should be spaced a distance approximately equal to twice the height of the ceiling (dimension B). Each
additional speaker in the row should use this same spacing.
Row 2 starts at twice the ceiling height distance (B) from row 1
and twice the ceiling height (B) from the wall.The other speakers
in this row are also spaced at twice the ceiling height.
Row 3 is again spaced at twice the ceiling height (B) from the previous row. The first speaker starting this row is positioned at one
ceiling height distance (A) from the wall (similar to row 1).
Continue this pattern of alternating rows until the room is covered.
The spacing of the speakers can be adjusted so that the speakers
are evenly spaced in a row and are more aesthetically pleasing.
START
HORN SPEAKER
1/2 C
C
D
Row 1
Row 2
Row 3
Row 4
The layout of the speakers should be planned before installation begins.The spacing of the speakers can be adjusted so that
the speakers are evenly spaced in a row. Some adjustments may need to be made due to sound obstructions that may be in
the area such as high shelving, cubicle walls, etc.
NOTE: Each environment is unique.This layout plan is general in
nature and may not be applicable for every installation.
Ceiling Speaker Layout
Horn Speaker Layout
START
C = See charts below
D = See charts below
TOP-DOWN VIEW
TOP-DOWN VIEW
SAH5A, AH5A
Low Noise
(55 dB-65 dB)
Medium Noise
(65 dB-75 dB)
(75 dB-85 dB)
High Noise
(75 dB-85 dB)
Very High
Noise
(85 dB-95 dB)
115
ft.
70
ft. LOW
107
ft.
65
ft. HIGH
107
ft.
65
ft. LOW
65
ft. MEDIUM
65
ft.
40
ft. HIGH
C
D
Volume Setting
Ambient
Noise Range
Medium Noise
100 ft.
SAH15A, AH15A
HS7EZHS15EZHS30EZ
Low Noise
(55 dB-65 dB)
Medium Noise
(65 dB-75 dB)
High Noise
(75 dB-85 dB)
Very High Noise
(85 dB-95 dB)
Very High Noise
(85 dB-95 dB)
120 ft. 80 ft. 1/2 Rotation
100 ft. 60 ft. Full Clockwise
100 ft. 60 ft. 1/2 Rotation
65 ft. 40 ft. Full Clockwise
90 ft. 55 ft. Full Clockwise
C
D
Volume Setting
Ambient
Noise Range
SPT5ASPT15ASPT30A
Ambient
Noise Range
Speaker
Power Taps
(Watts)
C
D
Low Noise
(55 dB-65 dB)
Medium Noise
(65 dB-75 dB)
Medium Noise
(65 dB-75 dB)
High Noise
(75 dB-85 dB)
Very High Noise
(85 dB-95 dB)
High Noise
(75 dB-85 dB)
Very High Noise
(85 dB-95 dB)
1.25W 100 ft. 65 ft.
7.5W 100 ft. 65 ft.
.9W 105 ft. 67 ft.
3.8W 100 ft. 65 ft.
15W 63 ft. 40 ft.
3.8W 103 ft. 68 ft.
30W 97 ft. 57 ft.
0
www.bogen.com
71
SYSTEM DESIGN GUIDE
Speaker Layout
20’ to 60’
10’
20’
SPEAKER
WALL
START
B=20 feet
A=10 feet
A
B
SPEAKER
START
• Hallway/Room
Wall baffle speakers work well with rooms and hallways that are
20' to 60' wide. Layout starts at one end of the hallway or room.
The first speaker should be installed 10' from the end of the hallway
or room.The next speaker on that wall should be installed 20'
from the first speaker, as should any additional speakers required
to cover the length of the hallway or room.
The first speaker on the opposing wall should be installed 20'
from the end of the hallway or room, thereby staggering the
speakers. Each additional speaker should also be installed 20'
apart from the previous one. (See Figure 1.)
• Open Area
The number of speakers needed to cover an open area and the
layout of those speakers is contingent upon the availability of
suitable mounting points in the area to be covered.
Layout starts in one corner of the room.The first speaker should
be installed 10' from the corner of the room with each additional
speaker in the first row installed in increments of 20' from the
first. Based on Figure 2, install the next row of speakers 30'
from the first row and 20' from the wall with increments of 20'
between each speaker. The third row would follow the example
of the first and each additional row would continue this pattern
of alternating rows until the whole area is covered.
Wall Baffle Speakers
The layout of the speakers should be planned prior to
installation. Because wall baffle speakers are designed to
project forward, it is best to aim them in the same
direction, as this provides for both greater coverage and
clarity.You can use the building’s roof pillars or other
available supports for mounting the wall baffles. In some
cases, it may be necessary to mount the wall baffles on
opposing walls. In these cases, the speakers will project
sound in opposing directions.
FIGURE 2
FIGURE 1
Ambient
Noise Range
Tap Setting
Low Noise
(55 dB - 65 dB
)
Medium Noise
(65 dB - 75 dB)
High Noise
(75 dB - 85 dB
)
Very High Noise
(85 dB - 95 dB)
1W
4W
Chart for 70V and 25V
passive speakers
Chart for self-amplified
speakers
www.bogen.com
72
SYSTEM DESIGN GUIDE
Site Survey
This Site Survey Check List will help to determine the paging system
equipment needed for installations. Photocopy this page and bring it with
you when you visit installation sites.You may need several copies of this chart for
each installation.
Section I – SYSTEM NEEDS concerns the requirements of the entire installation.
Section II – SPECIFIC AREA NEEDS
concerns specific areas within the installation.
I. SYSTEM NEEDS
Note: Installations that contain areas with different style environments or sound
levels may require Section II to be filled out separately for each area.
Be sure to make enough photocopies of this page for this purpose.
a. What Type of Telephone Port Will Be Available for Connection
to the Paging System? (see page 76)
❑
Loop Start
❑
Ground Start
❑
Page Port
❑
Analog Station Port
❑
Other: ____________________
b. How Many MIC Inputs Needed? _______ (see page 66)
c. How Many AUX Inputs Needed? ______ (see page 66)
d. Is Zone Paging Required?
❑
Ye s❑No (see pages 31-35)
If yes, how many zones: _________________
e. Is Talk Back Required?
❑
Ye s❑No (see page 50)
If yes, in individual zones?
❑
Ye s❑No (see pages 32-33)
If yes, system-wide (no zones)?
❑
Ye s❑No (see page 50)
f. Is Group Paging Required?
❑
Ye s❑No (see pages 31-35)
g.
Are Time Tones Needed to Signal Shift Changes?
❑
Ye s ❑No (see page 31-33, 51)
h. How Can Headend Equipment Be Mounted?
❑
Rack ❑Wall ❑Shelf
i. System Features Needed
❑
Aphex™Aural Exciter
❑
Variable Loudness Contour Control
❑
Automatic Level Control (ALC)❑Graphic Equalizer
❑
Bass & Treble Controls
❑
Variable Mute
❑
Automatic Mute
❑
Manual Mute
❑
MOH Output
❑
Night Ringer
j.
Any Technology Preference?
❑
None ❑70V Central Amplifier ❑Self-Amplified 24V Equipment
II. SPECIFIC AREA NEEDS
a. Area Name/Description: _________________________
b. Area Dimensions:
Length __________________ ft. Width ___________________ ft.
Square Footage ___________ sq. ft. Ceiling Height ____________ ft.
c. Ambient Noise Level: ____________ dB
(to estimate, see chart on page 77)
d. Will There Be Large Changes in Ambient Noise Levels in
the Area?
❑
Ye s ❑No (see page 38, 49)
If yes, note range: ____________ dB to ____________ dB
e. Environment:
❑
Office/Professional/Retail Store
❑
Factory/Industrial
❑
Institutional/Remote Public Area ❑Warehouse
❑
Aisles created by high storage racks❑Hallways
❑
Cafeteria/Break Room
❑
Auditorium
❑
Loading Docks/Outdoor Areas
❑
Other: ___________________
f. Where Will the Speakers Be Placed?
❑
Indoors ❑Outdoors
g. How Can the Speakers Be Mounted?
❑
Suspended/Drop Ceiling*
❑
Wall**
❑
Beams, Columns, Other Structures
❑
Ground
* Make note of any changes in surfaces or positions for actual speaker mounting.
** Make note of any changes in wall angles, surfaces, or height.
h. Are Volume Controls Mounted on Each Speaker Needed?
❑
Ye s ❑No
i. Are Wall-Mounted Attenuators Needed for Area’s
Volume Control?
❑
Ye s ❑No (see page 20, 27)
j. Is Feedback Elimination Equipment Needed?
❑
Ye s ❑No
(see page 51)
k. Is Background Music Needed?
❑
Ye s ❑No
If yes, BGM source: (see pages 53-55)
❑
Tuner
❑
Tape Player/Tuners
• Antenna Available for tuners?
❑
Ye s ❑No
❑
CD Player
❑
Other: ___________________
Designing a system and determining an installation’s requirements are
quite simple. After you set up your first system, the steps will appear
logical and soon the process will become routine.
Before you begin designing or quoting a job, you will need some basic
information regarding the site and the end-user’s needs. Use the Site
Survey Check List below to ensure that you collect all the information
you will need to complete the design of the paging system.When you
have completed the check list, create a bill of material for the
equipment you need for the installation’s sound system. Refer to the
Easy Design
™
Guide (pages 5-9), page 67 for 70V systems, or page
69 for 24V systems.
TToooollss NNeeeeddeedd
You will need to bring the following tools with you when you visit the
installation site:
• measuring wheel/tape measure • sound pressure meter
• calculator • Bogen Products catalog
• Photocopies of Site Survey Check List (this page)
Obtain a copy of the floor plan, or create sketches of any areas that
may require special design considerations (high shelving, speaker
mounting locations, exposed beams, amplifier location, etc.).
A successful paging system depends on more than just understanding
the physical requirements of the installation site, it also depends on
knowing which special paging features the user will benefit from and
use on a daily basis.These include zone paging, tone controls, night
ringer, feedback elimination, ambient noise sensors, multiple inputs, etc.
Site Survey Check List
www.bogen.com
73
SYSTEM DESIGN GUIDE
Speaker Wiring
Speaker Wiring Patterns
Because distributed paging systems involve a great number of
speakers and long distances, the manner in which the speakers are
wired is of interest. Deciding on how to wire the speakers depends
on whether separate zones of speakers are needed, how many
lines back to the amplifier are reasonable, and how easy it will
be to troubleshoot the system in the future.
How you wire a speaker system may require some tradeoffs.
The simplest way is to parallel all the speakers on one very long
run of wire.This approach leads to some problems. First, the
amount of power lost in a long run of wire may not allow the
required amount of 70V speaker signal, or 24V DC voltage for selfamplified paging systems, to get to the farthest speakers. Second,
if there should be a short on the wire run, it would take down
the entire run. In order to locate it, you would need to disconnect
each speaker until the failed one is found.
Multiple Wire Runs
A more practical approach is to wire each row of speakers in an
area together and run a lead wire from this row back to the
amplifier. The objective is not to have so many speakers daisychained together that it makes troubleshooting impossible.
Wire runs can be separated to determine in which run the
problem exists.
Speaker Phasing
As the voltage on a speaker changes from plus to minus, the speaker
cone moves from pushing out to pulling in. If you reverse the polarity,
the speaker responds in the opposite manner.
If a speaker is pushing out and an adjacent speaker is pulling in, some
of the pressure caused by the speaker pushing out will be absorbed by
the speaker pulling in.These two speakers are out of phase.
In a paging system, all the speakers should be in phase so that they all
push out at the same time. Out of phase speakers operate perfectly
well and will not cause any harm to a paging system, but will tend to
diminish the bass response in the area around the out
of phase speaker.
The important thing is to wire all the same polarity (+ or -) connections together. This will ensure that the speakers in the system all work
in unison.All paging speaker connections have a polarity indicator. It
may be a color code, plus (+) and minus (-) symbols, or a red dot.
+
_
+
_
+
_
+
_
Reversed Connections
in 70V System
AMP
or
24V Power
Supply
AMP
or
24V Power
Supply
_
+
_
+
_
+
_
+
_
+
_
+
_
+
_
+
_
+
_
+
_
+
_
+
_
+
_
+
_
+
_
+
_
+
_
+
_
+
_
+
_
+
_
+
_
+
_
+
www.bogen.com
74
SYSTEM DESIGN GUIDE
Wire Types
Speaker Wire
The speaker wire best suited for paging systems is 2 conductors
in a jacket.The gauge of the conductors varies depending on the
installation. In many instances, a shielded version of the speaker
wire is used.The shield can be useful to help protect the conductors from receiving electrical interference from other electrical
equipment in the area.The shield is particularly useful when
speakers are to be used as microphones in talk back applications
(see page 50 for more information on talk back).
• Two-Conductor Shielded Cable
Two-conductor shielded cable is typically used with balanced microphones.Two internal conductors are required for the low impedance balanced microphones used in paging systems.The shield is
wrapped around these conductors and provides the same protection against electrical interference and noise as single-conductor
cable. Balanced microphone inputs provide a ground connection
point for the shield.Without the ground connection, the shield
would be ineffective. Some microphones with push-to-talk switches
require two more conductors to carry the switch closure back
to the amplifier. In this cable, the conductors for the switch closure
are not wrapped in the shield but rather carried in the cable jacket outside of the shield.The most popular types of connectors
for microphone cable are screw terminals and XLR connectors.
Shielded Cable
Shielded cable refers to any conductor, or conductors, wrapped in
an electrically conductive shield.The two types of cable most
prevalent for audio installations are:
• Single-Conductor Shielded Cable
Single-conductor shielded cable is used to connect external
equipment to the unbalanced AUX inputs of amplifiers.The center
conductor carries the signal source and the shield carries the
ground between the amplifier and external equipment. In addition
to completing the ground return between the electrical equipment,
the cable provides a large amount of noise and interference
protection for the center conductor.The most common connector
for this type of cable is the Phono connector (a.k.a. the RCA
connector).The connector’s center pin connects to the internal
conductor and the skirt around the connector’s perimeter connects to the shield of the cable.
Jacket
Jacket
Shield (optional)
Shield
2 Conductors
Conductor
Drain Wire (optional)
SINGLE-CONDUCTOR SHIELDED CABLE
SHIELDED SPEAKER WIRE
Jacket
Shield
2 Conductors
TWO-CONDUCTOR SHIELDED CABLE
(BALANCED MIC CABLE)
UTP
Unshielded Twisted Pair wire has many uses but is most common in
data and telecom installations. It uses solid conductors, typically 24
gauge. It has insulation to withstand voltages similar to speaker wire
and can be used in 70V and self-amplified applications as long as the
thin gauge, and the associated higher resistance is accounted for.
Also, because there is no shield, the use of UTP in talkback applications (where the speaker acts as a microphone) may lead to higher
electrical noise on the talkback signal.There are normally several
twisted pair in a single cable and these can be paralleled to approximate lower gauge wires (see page 75).
Jacket
Twisted Pair
NON-SHIELDED UTP WIRE
LET US DESIGN IT FOR YOU...
FOR FREE!!!
—SEE PAGE 81 FOR DETAILS
www.bogen.com
75
SYSTEM DESIGN GUIDE
Wire-Related Losses
Maximum Wire Run Cable Length (ft.)
Wire Loss In Central Amplifier Systems
Once you have an idea of how many speakers are to be wired together
in a run, estimate how long the wire run will be from the first to the last
speaker in each run. Include the lead-in wire length from the amplifier to
the first speaker in each run in your overall run length. For each run,
sum up the speaker power and cable lengths.
With that information, refer to the Wire Loss Chart to ensure that the
wire gauge is sufficient to support the power and cable length for the
run. It may be necessary to increase the wire gauge, split the speaker
loads, or shorten the wire run lengths if they exceed the chart maximums.
Wire Loss Chart
(10% of Power Lost in Wire)
Wire
Gauge
16
10,000 7000 4600 2300 1400 700 350
18
9000 4500 2800 1400 830 415 205
20
5500 2700 1800 900 540 270 135
22
3400 1700 1100 550 330 11560
24
2100 1000 700 350 210 105 50
Load Power Per Wire Run (Watts)
5
1
0
1
53050100 200
Wire is an important but often ignored component of a paging
system. Because all wire has resistance, some of the voltage at the
source is lost or dropped in the wire before it reaches the target
destination.The amout of voltage lost in the wires is effected by the
resistance or gauge of the wire and the current flowing in the wire.
This is classic Ohm’s law in action. If the drops in the cables are
not anticipated, the final volume level at the passive speaker may
not meet the requirement or, for a self-amplified speaker, there
may not be engough DC voltage available to the speaker to allow
the built-in amplifier to operate cleanly, or at all.
We use different charts for centralized and self-amplified speakers
to determine the maximum cable lengths that should be allowed.
In the case of central amplifier systems we try to keep the system
power lost in the wires to 10% or less. However, less power at the
speaker is the only negative effect larger losses have on the system.
Clarity, intelligibility and frequency response are unaffected by larger
losses in the wiring of centrally amplified systems.
Self-amplified systems are particularly sensitive to losses in the wire,
especially the amount of supply voltage that is lost in the wires on
the way to the self-amplified speaker.When the drop in the wiring
becomes too large, the speakers may begin to distort or stop functioning altogether. For this reason it is important to adhere to the
maximums shown in the tables below.
Voltage Drop In
Self-Amplified Systems
The most important wiring consideration with selfamplified speakers is to ensure that there will be
enough voltage available at each device to allow its
internal amplifier to operate correctly. If too much
voltage is dropped in the wires leading to a speaker,
this may not be the case.
Once you have an idea of how many speakers are to
be wired together in a run, estimate how long the
wire run will be from the first to the last speaker in
each run. Include the lead-in wire length from the
power supply to the first speaker in each run. Also
sum up the CU ratings of all the speakers on the run.
With that information, refer to the Voltage Drop
Chart to ensure that there are not too many speakers
loading the wire used in the run or that the wire
gauge is sufficient to support the power and cable
length desired.To stay within the chart length limits
it may be necessary to either create a shorter run
containing less speakers or double up on conductors
in the cable to effectively lower the gauge of the
supply wire. The Reducing Gauge Chart can be
used to determine what effective gauge is achieved by
doubling or tripling up on pairs in the cable.
26 24 22 20 18 16
10
20
30
40
50
60
70
80
90
100
110
220'
110'
73'
55'
44'
37'
31'
28'
24'
22'
20'
351'
175'
117'
88'
70'
58'
50'
44'
39'
35'
32'
557'
279'
186'
139'
111'
93'
80'
70'
62'
56'
51'
887'
443'
296'
222'
177'
148'
127'
111'
99'
89'
81'
1413'
706'
471'
353'
283'
235'
202'
177'
157'
141'
128'
2237'
1118'
746'
559'
447'
373'
320'
280'
249'
224'
203'
Total CU (Current Units) on cable run
WIRE GAUGE (AWG)
VOLTAGE DROP CHART
REDUCING GAUGE
WIRE
GAUGE
(AWG)
26
24
22
20
18
16
24
22
20
18
16
14
22
20
18
16
14
12
Indicates maximum cable length (in feet)
www.bogen.com
76
SYSTEM DESIGN GUIDE
Telephone Interfaces
The most common way to make announcements over a paging system is through the telephone system. It is a convenient and readily available
live input source. However, audio and telephone technologies are different.This sometimes makes it necessary to use an adapter to link the two
systems together.
There are many types of telephone ports possible in telephone switches.The four types presented here – Page Port, Loop Start trunk, Ground
Start trunk, and Analog ring-up station – are the only ones Bogen recommends as interfaces to telephone systems. Other port types and specifically digital station ports are not suitable for connection to amplifiers and interface devices.
• The Loop Start, or CO port, is the most popular type of paging interface
to use when a page port is not available or suitable
• A Ground Start trunk uses loop current but employs a request and
acknowledgment hand shake for making the initial connection
• An interface device is necessary when connecting a trunk to an amplifier
• When paging, an interface adapter detects the off-hook condition of
the trunk and connects the amplifier to the trunk port through
signal conditioning electronics
• When the trunk is released, the adapter detects the on-hook condition
and immediately disconnects the amplifier from the trunk
• Trunk interface adapters require a power supply to provide talk-battery
and loop current to the trunk port
• A pop at the end of a page is typically present due to the large change
in telephone line voltage between on- and off-hook conditions
• An analog station allows interfacing when neither a paging port nor
a trunk port is available
• Analog ring-up interfacing requires a more sophisticated interface
than other methods
• The interface must detect a high-voltage ring signal and answer the call
to start the page
• To determine when to disconnect the page, typically two system timers are
used — one limits the maximum length of the page to ensure disconnection,
the other senses audio activity and disconnects after a preset length of silence
• Many telephone switches now provide calling party control (CPC) signal,
which indicates to the interface that the caller has disconnected;
Bogen interfaces disconnect immediately upon detecting a CPC signal
• Dedicated audio output available standard on most telephone systems
• Can be connected directly to the input of most amplifiers
• Traditionally a 600-ohm dry audio signal and a normally open
control contact closure
• Control contacts, if available, activate during a page and typically control
the muting of background music
• Some page ports provide only an audio pair, which requires that audio
equipment have voice-activated (VOX) functions such as background
music muting
• Paging ports are not always bi-directional like telephone lines
(bi-directionality is necessary when including talk back capability in
a paging system)
• Not all paging ports will produce DTMF tones which are necessary
when using zone paging equipment
BGM
IN
PAGING TIMEVOX DELAYTONE VOL.
MIN MAXMIN MAXMIN MAX
TAM B
TELEPHONE ACCESS MODULE
BOGEN
RAMSEY, N.J.
COMMUNICATIONS
S5
S5
VOX ENABLE
VOX DISABLE
S3
S4
PREANNOUNCE TONE
S3 S4
CONFIRMATION TONE
48VDC PWR SUPPLY S1,S2
24VDC PWR SUPPLY S1,S2
ONOFFMODE
RINGER EQUIVALENCE: 1.2 B
CD23CH-17705-KX-N
FCC REGISTRATION NUMBER:
COMPLIES WITH PART 68, FCC RULES
VOL
BGM
SWITCHES
MODE
(0.1A)
(TRUNK ACCESS ONLY)
POWER SUPPLY
CONTACT CLOSURE A
PAGING OUTPUT
EXT VOX ENABLE
PHONE SYSTEM
-24/48
+24/48
COM
N.O.
PR
PT
-M
+M
R
T
LOOP START
TRUNK PORT
T
R
POWER SUPPLY
+
-
PEAK LEVEL
POWER
BOGEN
AMPLIFIER
MODEL TPU
ALC
TEL VOLUME
MIC VOLUME
MUSIC VOLUME
MUSIC MUTE
RINGER VOLUME
VOX SENS
BASS
TREBLE
APHEX
PAGE PORT
T
R
1
2
AUDIO
CONTACT
CLOSURE
Page Ports
Loop And Ground Start
BGM
IN
PAGING TIMEVOX DELAYTONE VOL.
MIN MAXMIN MAXMIN MAX
TAM B
TELEPHONE ACCESS MODULE
BOGEN
RAMSEY, N.J.
COMMUNICATIONS
S5
S5
VOX ENABLE
VOX DISABLE
S3
S4
PREANNOUNCE TONE
S3 S4
CONFIRMATION TONE
48VDC PWR SUPPLY S1,S2
24VDC PWR SUPPLY S1,S2
ONOFFMODE
RINGER EQUIVALENCE: 1.2 B
CD23CH-17705-KX-N
FCC REGISTRATION NUMBER:
COMPLIES WITH PART 68, FCC RULES
VOL
BGM
SWITCHES
MODE
(0.1A)
(TRUNK ACCESS ONLY)
POWER SUPPLY
CONTACT CLOSURE A
PAGING OUTPUT
EXT VOX ENABLE
PHONE SYSTEM
-24/48
+24/48
COM
N.O.
PR
PT
-M
+M
R
T
ANALOG
STATION PORT
T
R
Analog Station
www.bogen.com
77
SYSTEM DESIGN GUIDE
Typical Ambient Noise Level Typical Environments
Sound Pressure Levels Chart
Very
High
Noise
High
Noise
Medium
Noise
Low
Noise
85-95 dB
75-85 dB
65-75 dB
55-65 dB
Speech
Almost Impossible
To Hear
Speech is Difficult
To Hear
Must Raise Voice
to be Heard
Speech is Easy
To Hear
95 dB
85 dB
75 dB
65 dB
55 dB
Construction Site
Loud Machine Shop
Noisy Manufacturing
Printing Shop
Assembly Line
Crowded Bus/Transit Waiting Area
Machine Shop
Shipping/Warehouse
Supermarket (Peak Time)
Very Noisy Restaurant/Bar
Bank/Public Area
Department Store
Noisy Office
Restaurant/Bar
Supermarket
Transportation Waiting Room
Conversational Speech
Doctor’s Office
Hospital
Hotel Lobby
Quiet Office
Very Quiet Restaurant/Bar
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