CHARACTERISTICS OF SOUNDS

Musical sound has the following characteristics:

1.      Loudness

2.      Pitch

3.      Quality or Timber 

LOUDNESS OF SOUND: - 

Definition: -

Loudness is that characteristics of musical sound which enables us to distinguish between a faint sound and a loud sound.

OR

Loudness is defined as the auditory sensation produced by the sound in ear.

Loudness of sound depends upon the intensity of sound. Loudness is actually a sensation of human consciousness. It is denoted by 'L'.

Loudness of sound is directly proportional to the logarithm of the intensity of sound

i.e.

L ∞ Log I

L = K (Log I)

Where "I" is the intensity of sound.

FACTORS ON WHICH LOUDNESS DEPENDS: - 

Area of vibrating body: -

The larger the area of vibrating body the louder the sound produced. For example a DHOOL produces a loud sound due to larger area. Similarly a small DHOLAC or CONGO produces a small loudness.

Amplitude of vibrating body:

The greater the amplitude of vibrating body, the louder the sound produced.

Distance b/w source and listener:

Smaller is the distance b/w source of sound and the listener greater is the loudness of sound as heard by the listener.

 PITCH OF SOUND: -

"The characteristic of sound by which a shrill sound can be distinguished from a grave sound is known as PITCH."

Pitch of sound depends upon the frequency of sound. The greater the frequency, the higher is the pitch and vice versa. It is the pitch of sounds that enable us to distinguished b/w a sound of man and woman or man and dog. Etc. sound of a woman is shrill due to high pitch. Sound of a dog is grave due to low pitch and low frequency.

QUALITY OR TIMBER: -

"The property of sound by virtue of which we can distinguish between two sounds of the Same pitch and the loudness originating from two different musical instruments."

The sound produced by two different instruments is usually complex. It is a mixture of several tones. The tone of lowest frequency is called Fundamental frequency and other tones are known as OVERTONES OR HARMONICS. The loudness of sound depends upon the amplitude of vibration. And pitch determined by its fundamental frequency. Two or more sound may have the same loudness and the same pitch but that they may differ in number and relative intensities of overtones. The quality of sound depends upon the wave form of the resultants. Nature has such a great diversity that it is very rare to have some overtones of two persons exactly. So this difference is overtones make it possible to recognize each sound. This characteristic of sound is called QUALITY.

INTENSITY OF SOUND: -

"The intensity of sound is defined as the amount of energy transmitted per second through unit area held perpendicularly in the direction of sound waves."

Intensity of sound = E / t. A

OR

I = E / t. A

Unit:

        In international system the unit is  Watt / m²