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Music by Handel
Water Music Suite - Allegro
Pre
ssu
re
Time
1 s
What we already learnt …
Amplitude
Amplitude
E.g.: Frequency = 2 Hz
•Graphical representation of the sound wave: Waveform
•Amplitude
•Frequency (No. of waves per second) =
Speed
Wavelength
Why do a man and a woman sound different?
What distinguishes one sound from another?What distinguishes one sound from another?
Why do a violin and a piano sound different?
Why do a rooster and a monkey sound different?
Goto
Musical Instruments Exploration
•Try out the instruments.
•Complete Section A on your worksheet.
•Pass instrument sets onto next group.
•You’ve got 5 minutes for each sets.
Total 3 sets.
Sound Characteristic 1: Loudness
The loudness of sound is dependent on the amount of energy which is transferred to the medium. It in turn is dependent on the amplitude of vibrations of the object.
Louder sound
Harder you hit the membrane(More energy transfer)
Larger amplitude of vibration
Sound Characteristic 1: Loudness
Compare the waveforms below:
Higher amplitude
!
What determines the loudness of sound?The amplitude of vibration.
Sound Characteristic 1: LoudnessCommon sounds and their estimated loudness:
SourceIntensity
Level# Times
Greater Than TOH
Threshold of Hearing (TOH) 0 dB 100
Rustling Leaves 10 dB 101
Whisper 20 dB 102
Normal Conversation 60 dB 106
Busy Street Traffic 70 dB 107
Vacuum Cleaner 80 dB 108
Large Orchestra 98 dB 109.8
Walkman at Maximum Level 100 dB 1010
Front Rows of Rock Concert 110 dB 1011
Threshold of Ear Pain 130 dB 1013
Military Jet Takeoff 140 dB 1014
Instant Perforation of Eardrum 160 dB 1016
One convenient unit of sound level:
The faintest sound a human ear can hear
is called the
Decibel (dB)
Threshold of Hearing
Sound Characteristic 2: Pitch
Sound waves are caused when a vibrating object introduce vibration into a medium.
Vibrating objects e.g. vocal cords, guitar string & sound board, tines of tuning fork, diaphragm of a radio speaker etc.
Medium e.g. air, water particles etc.
How often the particles of the medium vibrate when a wave passes through the medium is referred to the frequency of a wave.
Sound Characteristic 2: Pitch
Compare the waveforms below:
What determines the pitch of sound?
The frequency of vibration.
Higher frequency
!
Each vibrating object has its own frequency.
Sound Characteristic 2: Pitch
HumanHuman
?
Piano & GuitarPiano & Guitar
Sound Characteristic 3: Quality
Similar musical notes (i.e. same pitch) sounds different on different instruments (e.g. piano and guitar).
These sounds have different quality or timbre.
The quality of the pitch may be due to other weaker frequencies (called overtones), or deliberately mixed (as with a synthesizer).
Sound Characteristic 3: Quality
Compare the waveforms below:
What determines the quality of sound?
The waveform.
What we learnt today …
Soft LoudLoudness
Quality or Timbre
Pitch
depends on the amplitude of vibration
depends on frequency
depends on waveform
Low High
Mixed
Characteristics of sound
Clearer
Some time for reflection…Some time for reflection…
Have a sound Have a sound day!day!Have a sound Have a sound day!day!
A) Laryngeal prominence (Adam's Apple)
B) Larynx (voice box) (vocal cords inside)
C) Trachea (wind pipe)
D) Esophagus (swallowing tube)
As one reaches puberty, the larynx grows for both boys and girls.
Most girls’ larynx however don’t grow as much as boys’.
Larger larynx gives a deeper voice => lower pitch.
Our larynx (vocal box) is just like a wind instrument.Discuss how blowing into a column of air changes pitch when we vary:
The length of the air column
Goto
Shorter column
Longer column
Shorter wavelength Higher frequency
Longer wavelength Lower frequency