Bogen TPU 100 Guide
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
Loading...