Characterizing Sound

Sound is described by

  1. Pitch
  2. Loudness
  3. Quality or Timbre

What is the difference between sound intensity and loudness?

By how much do you have to increase the intensity of a sound to double its loudness?

How is the sound level in decibels determined?

Describe the threshold of hearing.

Why are hearing curves needed? What do you learn from them?




*Sound intensity

*Rule of thumb for loudness

*Critical band



*Threshold of hearing

*Equal loudness curves

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Sound measurement

Describe the shortcomings of the decibel scale for sound measurement.

Describe the phon scale for loudness measurement.

How can you improve upon decibels for practical sound measurements?

Why are straight decibel measurements often misleading in the assessment of the loudness of sounds?

What is the A contour? What advantages are there in making sound measurements using the A-contour filter?

What consistent effects do sustained loud sounds have on human hearing?


*Threshold of hearing

*Equal loudness curves

*Loudness in phons

*Shortcomings of decibels

*Contour filters

*A contour measurement

*Practical sound measurement

*Concrete drill

*Fire alarm


*Effects of loud sounds

*Temporary threshold shifts

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Sound quality or timbre

What is meant by sound quality or timbre. What are the three major contributors to sound quality?

Vowel sounds differ in quality (timbre) but may have identical pitch and loudness. How are the differences in vowels produced by the vocal mechanism? How does the ear detect the differences?

What is involved in sound analysis and synthesis?

Why are geometric waves commonly used in synthesizers?

*Perceived sound characteristics

*Quality (timbre)

*Harmonic content

*Attack and decay


*Harmonic spectrum

*Vocal formants

*Effect of pitch on vowel spectrum

*Ear as harmonic analyzer

*Sound synthesis

*Geometric waves

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