ACOUSTICS AND THE ELEMENTS OF MUSIC

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ACOUSTICS AND THE ELEMENTS OF MUSIC
Is your name and todays date at the top
of the worksheet now?
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Goals for Todays Talk-
Acoustics Sound Waves Four Characteristics
(elements) of Sound Relate Characteristics back
to Garage Band
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Acoustics WS

• Acoustics is the study of the BEHAVIOR OF SOUND
  WAVES.
• Every sound we hear is produced by VIBRATIONS.
• 3. Air disturbances move OUTWARD FROM A VIBRATING
  BODY IN THE FORM OF SOUND WAVES.

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Acoustics WS

• 4. A single vibration (one complete sound wave)
  is called a CYCLE.
• 5. On the line below, diagram a complete wave
  cycle.

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Acoustics WS

• TYPES OF SOUND WAVES
• 1) Sine Wave
• 2) Triangle
• 3) Pulse/Square
• 4) Sawtooth

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Acoustics WS

• 6. Name the four basic elements
  (characteristics) of all sound give them a
  brief definition
• ELEMENTS DEFINITION
• 1) DURATION LENGTH OF SOUND HOW IT STARTS
  ENDS
• 2) AMPLITUDE VOLUME HOW LOUD OR SOFT THE SOUND
  IS
• 3) FREQUENCY PITCH HOW HIGH OR LOW THE SOUND
  IS
• 4) TIMBRE DIFFERENT TONE COLORS OF SOUNDS

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Acoustics WS

• Frequency
• The frequency (PITCH) of a sound is determined by
  the NUMBER OF CYCLES THAT OCCUR IN ONE SECOND OF
  TIME.
• Example- (A440 tuner. Talk about cycles per
  second octaves, et al.)

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Acoustics WS

• Calculate the cycles per second. Determine the
  Highest and Lowest in PITCH of your given
  waveforms.
• (How many cycles on each line?)
• A 4
• B 2
• C 10.5
• Which wave is
• Highest in Pitch - C
• Lowest in Pitch - B

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Acoustics WS

• 9. The audible range for the human hearing is
  FROM 20 cps to 16000 cps.
• (cps is the abbreviation for CYCLES PER
  SECOND.)
• 10. Vibrations above 16000 cps are called
  ULTRASONIC and below 20 cps are called SUBAUDIO.
  (Examples of uses of these two types of wave.)

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Acoustics WS

• 11. The lower the cps or Hz, THE LOWER THE PITCH
  OF THE SOUND
• The higher the cps or Hz, THE HIGHER THE PITCH OF
  THE SOUND.
• (Note- Hz stands for Hertz. He discovered how
  to calculate cycles per second.)
• On Garage Band you change frequencies when you
  play different notes on the keyboard or use pitch
  bend.

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Acoustics WS

• Amplitude
• Amplitude is determined by STRENGTH OF THE FORCE
  THAT SETS THE SOUNDING BODY IN MOTION .
• (This is shown by the HEIGHT OF THE WAVES
  PEAKS.)
• 14. Example(tuner voice)

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Acoustics WS

• Which wave is
• -loudest? B
• -softest? A
• -gradually getting softer? C
• On Garage Band you change Amplitude by striking
  the keys harder or softer, changing the velocity,
  or adjusting a tracks volume.

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Acoustics WS

• Timbre and Waveshapes
• 16. Every sound (instrument/voice, etc.) is
  identified by its own unique TIMBRE.
• 17. Different timbres (tone colors) are
  determined by PRESENCE OF DIFFERENT COMBINATIONS
  OF OVERTONES ABOVE A FUNDAMENTAL NOTE.

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Acoustics WS

• A Fundamental note is THE BASIC NOTE THAT YOUR
  EAR HEARS.
• 19. Overtones are INDIVIDUAL NOTES PITCHED ABOVE
  THE FUNDAMENTAL. OUR EARS BLUR THEM TOGETHER.
  THEY ALLOW OUR BRAINS TO DISTINGUISH ONE
  INSTRUMENT OR VOICE FROM ANOTHER.

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Acoustics WS

• In the space on your paper, show a sample of the
  fundamental and overtone series
• Overtones
• Fundamental

Minor 3rd
Perfect 5th
Major 3rd
Perfect 4th
1 octave
Perfect 5th
1 octave
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Acoustics WS

• Timbre and Waveshapes
• In Garage Band you pick the Timbre you want when
  you choose a certain sound with which to record.
• You can also adjust the Timbre by using the
  Sound Generator under the Edit tab in the side
  Info window.

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Acoustics WS

• Duration Envelopes
• 21. The Duration of a note refers to HOW LONG THE
  NOTE IS HELD DOWN OR SUSTAINED.
• 22. The Envelope of a note refers to HOW THE NOTE
  STARTS AND ENDS.

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Acoustics WS

• 23. A synthesizer uses an ENVELOPE GENERATOR to
  set the parts of a notes duration. It usually
  has three parts
• Attack Sustain Decay/Release
• (Time) (Key Held Down) (Time)
• In Garage Band, you can adjust the Envelope of
  the sound using the Sound Generator under the
  Edit tab in the side Info window.

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Acoustics WS

• Questions . . .