BU3_LECTURE6.pdf

HOLY ANGEL UNIVERSITY
COLLEGE OF ENGINEERING AND ARCHITECTURE
DEPARTMENT OF ARCHITECTURE
Building Utilities 1 (Lighting and Acoustics) 1
BUILDING UTILITIES 3

BUILDING
UTILITIES 3
SOUND REINFORCEMENT SYS.
Lecture 6
COMPONENTS & SPECS.
6

SOUND SYSTEM
SOUND REINFORCEMENT SYSTEM
 A sound reinforcement system is the combination
of microphones, signal processors, amplifiers,
and loudspeakers that makes live or pre-recorded sounds
louder and may also distribute those sounds to a larger or
more distant audience.
 In some situations, a sound reinforcement system is also used
to enhance the sound of the sources on the stage, as
opposed to simply amplifying the sources
unaltered/unchanged.

SOUND SYSTEM
SOUND REINFORCEMENT SYSTEM
 A sound reinforcement system may be very
complex, including hundreds of microphones,
complex audio mixing and signal
processing systems, tens of thousands of watts of
amplifier power, and multiple loudspeaker arrays,
all overseen by a team of audio engineers and
technicians.
 On the other hand, a sound reinforcement system
can be as simple as a small public address (PA)
system, consisting of a single microphone
connected to an amplified loudspeaker. In both
cases, these systems reinforce sound to make it
louder or distribute it to a wider audience.

SOUND SYSTEM
PUBLIC ADDRESS SYSTEM
 Public address system also known as PA system
are widely use all over the world.This system as
the name suggests is required when there is a
mass of public to addressed at a single point of
time.This is basically used in school, auditoriums,
public announcements and by officials for public
use.
 This system makes it easier to communicate with
the crowd with no much effort. It’s different with
the music system used in concerts and used
mostly for reproducing a speech.

SOUND SYSTEM
A CONCERT GROUND WITH HIGH DENSITY OF EXPECTATORS

SOUND SYSTEM
BASIC CONCEPT
 A typical sound reinforcement system consists of;
1. input transducers (e.g., microphones), which convert
sound energy into an electric signal,
2. signal processors which alter the signal characteristics
(e.g., equalizers, compressors, etc),
3. amplifiers, which add power to the signal without
otherwise changing its content.
4. output transducers (e.g., loudspeakers), which convert
the electric signal back into sound energy.
 These primary parts involve varying amounts of individual
components to achieve the desired goal of reinforcing and
clarifying the sound to the audience, performers, or other
individuals
 Transducer – A Device that converts one form of energy to another
form (signal)

Basic Sound Reinforcement System

 DIFFERENT USES OF A PA SYSTEM
1. In school hall, auditoriums, for making announcement
of certain principal or compliance order
2. For events like seminars wherein one needs to address
a mass of people and to conduct a group discussion
smoothly and vividly
3. At open public places for inquiry announcements, and
often for lost and found departments too
4. Parties wherein a sophisticated message is to be
delivered to a particular group
5. These systems are used in church halls to. For making
prayer in a large group of devotees and maintaining the
integrity and silence along.

SOUND SYSTEM
Microphone
 A microphone is an acoustic-to-
electric transducer or sensor that converts sound
energy into an electrical signal.
 Microphones are used in many applications such
as telephones, tape recorders, karaoke systems, 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.

SOUND SYSTEM
Digital Signal Processor
 MIXING CONSOLE or AUDIO MIXER: is an
electronic device for combining, routing and
changing the level, timbre and/or dynamic of
audio signals.
 This is the most important element in a PA
system. It consists of tools to cater the needs of
how many channels at a time to deliver music
equalization and many more.

SOUND SYSTEM
Amplifiers
 An amplifier, is an electronic device that
increases the power of a signal. It does this by
taking energy from a power supply and
controlling the output to match the input signal
shape but with a larger amplitude. In this sense,
an amplifier modulates the output of the power
supply.

SOUND SYSTEM
Loudspeaker
 A loudspeaker (or "speaker", or in the early
days of radio "loud-speaker") is an electro-
acoustic 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.

Building Utilities 1 (Lighting and Acoustics)
BUILDING UTILITIES 3

BUILDING
UTILITIES 3
NOISE CONTROL
Lecture 6
PARTS AND SYSTEM
7

Noise control in the bldg. envelope
1. Sound-attenuating external walls
 Where external walls face a source of outdoor
noise, they should be of heavy construction and
without windows or doors if possible.
 If doors or windows are necessary, doors should
be solid with seals around the opening, and
windows should preferably be non-opening, using
sound-attenuating laminated panels.

1. Sound-attenuating external walls
 Acoustic performance of framed walls may also be
improved by:
 using staggered stud framed construction
 incorporating proprietary sound absorbing materials
into the ceiling construction
 using a proprietary acoustic rated wall construction
system.

Sound-attenuating
external walls
External sound envelope
(Fiber-cement cladding)
A high-density sheet cladding,
with sealed joints, thermal insulation,
and sound attenuating interior lining.
This will provide sound
reduction at moderate cost,
using lightweight construction.

Sound-attenuating
external walls
External sound envelope
(brick veneer)
A brick or concrete masonry veneer,
a rigid air barrier, thermal insulation,
and sound attenuating interior lining
is an expensive option
using heavier weight construction.
It will provide effective sound
reduction.

Sound-attenuating external walls
External sound envelope (concrete masonry)
A high density sheet cladding installed over battens, interior strapping,
thermal insulation and sound-attenuating interior
lining will provide an effective sound barrier.

2. Sound-attenuating roofs
 Sound-attenuating roofs are difficult to achieve.
One option is a concrete slab roof but this would
only be justified in extreme circumstances such as
under the flight path of planes at low level.

 Other options that include the ceiling construction as an
integral part of the sound attenuation system:
 Bitumen-impregnated underlay under long-run
profiled metal roofing – a low-cost option that will
reduce rain noise, but most other noise will be
transferred through the fixings.
 Concrete or tiled roofing – this will reduce the
impact noise of rain and hail but airborne noise will
be able to penetrate through the gaps in the roofing.

 Other options that include the ceiling construction as an
integral part of the sound attenuation system:
 Long-run profiled metal roofing with plywood
underlay, thermal insulation, a sound-attenuating
ceiling without down-lights, no roof lights and the
roof vented on the side away from the source of
noise – this will provide effective sound reduction.
 Incorporating proprietary sound absorbing materials
into the ceiling construction.

3. Sound-attenuating external window & door.
 Windows
Windows in walls that must be sound-attenuating should
preferably be non-opening, since air currents carry sound.
Options for sound-attenuating windows:
 Noise-reducing laminated glass – the best option that will
provide significant sound reduction as long as the window is
not opened.
 IGU (Insulated Glass Unit) – an effective option as long as
the window is not opened.
 Fitting additional glazing to the window reveal – a very
effective option although it may prevent the window being
opened.

 Windows
 When windows are open, any sound rating is lost. In some
situations, windows may only need to be closed for part of
the day such as during rush hour or during school break
times.
 Where windows must remain closed to reduce noise,
mechanical ventilation systems may be needed to replace the
lost ventilation.

 Doors
Sound-attenuating doors should:
 be solid core doors.
 not have glazed panels, or be fitted with sound-stopping
laminated glass.
 have brush, foam or rubber seals all round.

Four noise control mistakes to avoid
 Thinking that there is no noise problem!
Greater than 85 dB in factory environment and level
as low as a 55 dB in a class room/studios should be
considered as a problem. In general, if conversation
is difficult, treat it as a serious noise issue

 Not considering noise control during the
design stage :
Although all source of noise can be treated after
installation, it’s generally twice as expensive and half as
effective compared with designing proper noise
control into the system before the noise source is
installed

 Not sealing the air leaks :
Sound always takes the easiest path around or through
a barrier. Construction gaps or air leaks are the
easiest way for sound to pass from one space to
another

 Not using a systems approach to noise
control :
A common mistake in noise control effort is the
failure to consider all possible noise paths.All airborne
and structure borne noise paths must be studied and
treated accordingly

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