1. An Introduction to PA (Public Address) system
Written & Edited by : Mohammed Zaid Shaikh
+97152-5953641

2. Public Address System
A public address system : (PA
system) is an electronic sound
amplification and distribution
system with a microphone, amplifier
and loudspeakers, used to allow a
person to address a large public.
The term is also used for systems
which may additionally have a
mixing console, and amplifiers and
loudspeakers suitable for music as
well as speech, used to reinforce a
sound source, such as recorded
music or a person giving a speech or
distributing the sound throughout a
venue or building.
Public Address System
Public Address System : (Definition :1)

3. Public Address System
What is a PA System?
A “Public Address” system is
anything that amplifies sound so
more people can hear it. The most
basic example might be a
megaphone, or single microphone
and speaker, used to make
someone’s voice louder.
Public address systems consist of
input sources, amplifiers, control
and monitoring equipment, and
loudspeakers. The primary input
sources are microphones for live
announcements and a source of
recorded sound.
Public Address System : : (Definition :2)

4. Public Address System
There may be a system which allows operators, or
automated equipment, to select from a number of
standard prerecorded messages. These input
sources are fed into preamplifiers and signal routers
that determine the zones to which the audio signal
is fed.
The preamplified signals are then passed into the
amplifiers. Depending on local practices these
amplifiers will usually amplify the audio signals to
50V, 70V or 100V speaker line level. Control
equipment monitors the amplifiers and speaker
lines for faults before it reaches the loudspeakers.
This control equipment is also used for separating
zones in a PA system. The loudspeaker is used to
convert electrical signals into sound.

5. Public Address System : Microphone
A Microphone :
(colloquially called a mic or mike;
both pronounced /ˈmaɪk/)
is an acoustic-to-electric transducer
or sensor that converts sound into an
electrical signal. Microphones are
used in many applications such as
telephones, tape recorders, hearing
aids, motion picture production, live
and recorded audio engineering, FRS
radios, megaphones, in radio and
television broadcasting and in
computers for recording voice,
speech recognition, VoIP, and for
non-acoustic purposes such as
ultrasonic checking or knock
sensors..

6. Public Address System : Mixer
Mixer
There have been two
conventional categories of
live sound mixers for quite
awhile: powered and
unpowered analog mixers.
Now there is also a new
generation of digital
consoles designed for
studio and live sound
applications that bring the
added benefits of total
recall mixing and onboard
effects.
Powered Mixers
Digital Mixers

7. Public Address System : Amplifiers
Amplifiers
Amplifiers
An Amplifier:
is a device for increasing the power of a signal
by use of an external energy source.
In an electronic amplifier, the input "signal" is
usually a voltage or a current.
Other types exist; a fluidic amplifier increases
the power of signals represented as flow of
gas or liquid, for example. Amplifiers may be
classified in a variety of ways depending on
their application, the frequency range they
cover, or the active devices used. Ideally an
amplifier increases the power of a signal
without otherwise altering it; practical
amplifiers have finite distortion and noise
which they invariably add to the signal.

8. Public Address System : Loudspeaker
Loudspeaker
A Loudspeaker (or "speaker") is an Electroacoustic
transducer that produces sound in response to an
electrical audio signal input.
Non-electrical loudspeakers were developed as
accessories to telephone systems, but electronic
amplification by vacuum tube made loudspeakers
more generally useful. The most common form of
loudspeaker uses a paper cone supporting a voice
coil electromagnet acting on a permanent magnet,
but many other types exist. Where accurate
reproduction of sound is required, multiple
loudspeakers may be used, each reproducing a part
of the audible frequency range. Miniature
loudspeakers are found in devices such as radio
and TV receivers, and many forms of music players.
Larger loudspeaker systems are used for music,
sound reinforcement in theatres and concerts, and
in public address systems.

9. Public Address System
Wired in PA System
Wired in PA System :
A public address system (PA system) is
an electronic amplification system with
a mixer, amplifier and loudspeakers,
used to reinforce a sound source, e.g., a
person giving a speech, a DJ playing
pre-recorded music, and distributing
the sound throughout a venue or
building.

10. Public Address System
Wireless Public Address and Intercom Solutions
Wireless Public Address and
Intercom Solutions :
Public address & intercom line of
products, offers an easy and
economical way to incorporate a
two-way Public Address system
for daily and emergency
announcements throughout any
type of facility. College
campuses, schools, medical
centers, office buildings,
manufacturing plants, military
bases and other facilities.

11. Public Address System : Distribution Amplifier
Distribution Amplifiers :
A complete range of distribution amplifiers are made
by Precision Test Systems. A distribution amplifier is
used to distribute the output of a frequency
reference to many different places. Usually the
frequency is 5 or 10 MHz.
In electronics, a distribution amplifier or simply
distribution amp, is a device that accepts a single
input signal and provides this same signal to multiple
isolated outputs.
These devices are important because they allow a
signal to be distributed to multiple destinations
without ground loops or signal degradation. They are
used for a number of common engineering tasks,
including multiple amplification, cable television,
splitting monitor and front of house mixes, and
"tapping" a signal prior to sending it through effects
units to preserve a "dry" signal for later
experimentation.
Distribution Amplifier Delivers Full HD Output to 4 Displays.

12. Public Address System : Audio Power Amplifier
Audio Power Amplifier
An audio power amplifier is an electronic
amplifier that amplifies low-power audio
signals (signals composed primarily of
frequencies between 20 - 20 000 Hz, the
human range of hearing) to a level suitable for
driving loudspeakers and is the final stage in
a typical audio playback chain.
The preceding stages in such a chain are low
power audio amplifiers which perform tasks
like pre-amplification, equalization, tone
control, mixing/effects, or audio sources like
record players, CD players, and cassette
players. Most audio power amplifiers require
these low-level inputs to adhere to line levels.
While the input signal to an audio power
amplifier may measure only a few hundred
microwatts, its output may be tens, hundreds,
or thousands of watts.

15. Public Address System
8 Steps to building your first PA system
If you've ever thought to yourself, "What do I need to put
together a PA system?", you've come to the right place! While
While there is a lot to know about sound reinforcement, this
this article is meant to give you some basics regarding the
the various components of a live sound system - just enough
enough to get you pointed in the right direction. There is a
a TON of additional information in the Live Sound Buying
Buying Guides, a LOAD of live sound equipment to choose
choose from online right at Sweetwater, and we welcome
welcome your phone call at 1-800-222-4700 where you can
can speak with someone who understands the ins and outs of
outs of live sound and can further answer your questions.
questions.
Just about every live sound system (or"PA" system) is
comprised of the following basic components. Just follow this
follow this step-by-step guide and you'll find that building
your own system is completely within reach.

16. Public Address System
Step – 3 : Choose Appropriate PA Speakers
Choose Appropriate PA Speakers
PA speakers can be active (powered) or
passive (unpowered). "Active" means that the
speakers have amplifiers built in, which
provides the advantage of not having to buy,
carry, and match speaker to a power amp.
Conversely, passive speakers do not have
built-in amplification, but they come in a wide
variety of configurations, generally have a
much higher power capacity, and can be
convenient if you already own power amps.
Beyond choosing powered or unpowered,
there are a number of other factors to consider,
such as bi-amped, tri-amped, and whether or
not to add a subwoofer to your system.

17. Public Address System
Step – 4 : Pick Out the Right Monitor System
Pick Out the Right Monitor System
Your vocalist will be more likely to sing
in key, your bass and drummer will be
more likely to play in the pocket, and
your lead guitar player will know when
to stop playing licks IF they can all hear
what's going on. There are more options
today for stage monitoring than ever
before. You can go with traditional
unpowered stage wedges, in-ear
monitoring systems (wired or wireless),
smaller stage fills, and/or powered
solutions.
Wireless Monitor System ...
Wired Monitor System ...

18. Public Address System
Step – 5 : Get the Right Power Amplification
Get the Right Power Amplification
If you're going with a powered mixer
or powered speaker system, then you
might not need outboard amps at all.
However, if you need to match a power
amp to a PA speaker, a general rule of
thumb is to pick an amplifier that can
deliver power equal to twice the
speaker's continuous IEC power rating.
This will allow for extra headroom
offering clean, undistorted power.
Stereo Audio Power Amplifier

19. Public Address System
Step – 6 : Add Signal Processing
Add Signal Processing
Signal processing (effects) for live sound
usually involves reverb and delay, EQ
(graphic or parametric), and compression
and limiting. It is important to choose an
effects processor that is optimized for
live performance. Like powered mixers,
effects processing is another area where
all-in-one products like the DriveRack
PA by dbx are simplifying and greatly
improving the quality of live sound.

20. Public Address System
Step – 7 : Cable up Your Rig
Cable up Your Rig
Often overlooked (until you actually try to get
sound out of your live sound rig that is), good
cables and proper cable management will mean
the difference between your audience getting to
hear your music or not. Because cables tend to
be abused in live performance situations, we
strongly suggest solid cables that will last. To
begin with, you'll need enough microphone
cables to handle your mic setup, plus line or
speaker cables to run from your mixer to the
speakers.

21. Public Address System
Step – 8 : Rack Up and Pack Up Your Equipment
Rack Up and Pack Up Your Equipment
Whether you're planning to gig out live by
yourself at your favorite coffee house, or on a
national tour with a ten-piece band, keeping your
gear and other sound "stuff" organized in
properly constructed racks and cases will allow
you to set up and take down quickly and let's
face it, your investments will last a lot longer
than if you lugged it all around in your father's
old suitcases. If you plan on going out on the
road, a wood-constructed hard case rack is what
your rack mount gear will need, but for those of
us playing out around town, the molded plastic
style portable racks suffice nicely. Be sure to
plan for the future. Try to purchase a rack that
allows for room to grow.
Rack Up Equipment
Rack Up Equipment

22. Thank you