3. Pitch
Pitch refers to the highness or
lowness of a sound.
The pitch of a sound that you hear
depends on the frequency of the sound
wave.
4. Pitch and Frequency
• Sound waves with a high frequency have a high pitch
and sound waves with a low frequency have a low
pitch.
5. • High frequency means more vibrations hitting the ear.
• Pitch is how high or how low a sound seems to be.
• Healthy humans can hear from 20 Hz to 20,000 Hz
• We are most sensitive from 440 Hz to 7,000 Hz.
6. Changing Pitch
• Lungs: Air From the lungs
rushes up the trachea
• Vocal Cords: which are
located in your voice box,
or larynx vibrate as air
rushes pass them
• Sound: Sound waves
produced by the vibrating
vocal cords come out
through the mouth
7. •A man’s vocal chords are
normally longer and more
massive than a female’s
voice. Hence, a male’s voice
is low pitched compared to
the female’s voice.
10. The degree of loudness or faintness of
a sound depends upon the different
factors
1. Amount of energy of a sound
2. Distance from the source of sound
3. The state of the medium through which the
sound is transmitted
4. The amount of the original vibrations
5. The frequency of the vibration
6. Area to which the sound is produced
11. Energy of a Sound Source
The greater the energy
used to make a sound, the
louder the sound
Example: Playing a guitar
When you use more energy
to pull the strings of the
guitar the louder the noise
produced by the guitar is.
12. The more energy you use, the larger
the amplitude
The larger the amplitude produces a
louder sound.
Amplitude is the distance between the normal
position to the final position of an object which is
producing specific vibration.
13. Distance From a Sound
Source
Loudness increases the closer you are to a sound source.
– Close to the sound source, the sound waves cover a small
area
– As waves travel away from the sound source, it covers more
area
The total energy of the wave stays the same whether it’s close
to the source or far away from it
– The closer the sound wave is to its source, the more energy
it has in a given area.
14. Distance From a Sound
Source
The amount of energy a sound wave
carries per second through a unit area is
its Intensity
A sound wave of greater intensity sounds
louder
When you move away from the sound
source, loudness decreases, because the
intensity decreases.
15. Measuring Loudness
Loudness is measured using the unit called
the Bel (B) in honor of Alexander Graham Bell. A
bel is a rather large unit; the smaller unit is
decibel (dB) is often used instead.
1B = 10dB
16. Intensity Levels of Common
Sounds
Source of Sound Intensity level
in dB
Intensity I (W/m2)
Threshold of hearing O 1 × 10-12
Rustle of Leaves 10 3.2 × 10-11
Whisper 20 1 × 10-10
Ordinary conversation 65 3.2 × 10-6
Busy street traffic 70 1 × 10-5
Auto interior moving at 90 kph 75 2.8 × 10-4
Loud indoor rock concert 100 1 × 10-2
Threshold of pain 120 1 × 101
