Multimedia Systems Psychoacoustics and Acoustics

1. ‘ SOUND ’

2. WHAT IS SOUND..?
Definition -
“ Vibrations that travel through the air
or another medium and can be heard when
they reach a person or animal‟s hear. ”

3. I N T R O D U C T I O N
 Sound comprises the spoken word, voices, music and
even noise.
 A pleasant sound has a regular wave pattern. The pattern
is repeated over and over.
 But the waves of noise are irregular. They do not have a
repeated pattern.

4.  Noise:
 Noise can be defined as ‘undesirable’ or ‘disagreed’
sound or disturbance.
 What is sound to one person can very well be a noise to
somebody else.
 Sound is been measured in (dB) decibels.

5. RECORDING AUDIO (SOUND) FILE'S.
- Microphones:
connect microphone to the microphone port and record using
sound recorder or via system software.

6.  Sound is reflected, transmitted, or absorbed by the materials it encounters.
 Soft surfaces, such as textiles and tend to absorb sound waves, preventing
them from further motion.
 hard surfaces, such as ceramic tile, wood, tend to reflect sound
waves, causing „echo‟. Reverberation is the term used to describe sound
waves that are reflected off of surfaces.
 Dense, massive, materials, such as concrete or brick, tend to transmit sound
waves through the material.

7.  Definition:
- “ A science that deals with the
production, control, transmission, reception, and effects of sound. ”
For example, dog whistles vibrate at a higher frequency than the
human ear can detect, while evidence suggests that dolphins
and whales communicate at frequencies beyond human
hearing (ultrasound).
Many animals hear a much wider range of frequencies than
human beings do.

8.  Sound is a mechanical wave and therefore requires a medium
in which it can travel.
 Acoustics is classically divided into sound and vibration.
 Sound refers to waveforms traveling through a fluid medium
such as air.
 Vibration describes energy transmitted through denser
materials such as wood, steel, stone, dirt, drywall or anything
besides a fluid.
 It is not heard as much as felt, due to its extremely low
frequency, which is below the range of most human hearing.

9.  Sub – Disciplines of Acoustics :
 Aero-Acoustics - Its concerned with how the gas flows produce sound & has
applications in aeronautics. Eg. Sound and Shockwaves produced by jets.
 Architectural-Acoustics - Its concerned with the study of sound in buildings
like halls & auditoriums.
 Bio-Acoustics - Its done with the sound made by animals like Elephants ,
Whales, Bats, etc.;
Biomedical-Acoustics - Its concerned with the study of sound in the medicines,
Eg. Ultrasonography, psycho-acoustics concerned with the hearing & localization
of sound related to human beings;

10.  Sub – Disciplines of Acoustics :
 Speech Communication – Concerned with the production
, analysis, transmission & recognition of speech.
 Ultrasonic – Its the study of High frequency sounds beyond
human range.
 Musical-Acoustics – Concerned with the study of sound in
relation to musical instruments. Eg. Guitar

11.  DEFINITION :
- “ the study of hearing - relationship between the physical properties of
sound and the sensations they produce. ”
- Hearing – the process that transforms sound waves into neural signals
that can be interpreted by our brain.
- Sound Waves - fluctuations in air pressure across time, created by the
motion or vibration of an object (e.g. the vibration of violin string).

12. WHAT IS PSYCHOACOUSTICS ?
 Psychoacoustics is a branch of
science studying psychological
responses associated with sound
(speech & music).

13.  Psychoacoustics has enjoyed a relation with Comp. Science, Comp.
Engineering & Computer Networking.
 It’s also applied today with music, where the musicians & artists continue
to create the new auditory experiences by removing unwanted frequencies
of instruments.
 It studies the relationship between & perception of sound in order to
explain auditory behavioral responses of human listeners.

14. Psychoacoustics include topics related to music
psychology also known as musicology.
It aims to explain & understand musical behavior.
Music psychology is a field of research with the
music performance, music composition, music
education etc.

15. S U B J E CT - M U L T IME DIA S Y S T EMS
Presented by :
Fahad Shaikh..

16. THANK YOU