1. Chapter 21 – The Nature of Sound
Section 4 – Sound Quality pp

2. TERMS TO LEARN
Sound quality – the result of several pitches blending together through interference

3. WHAT IS SOUND QUALITY?
If the same note is played with the same loudness on two different instruments, could you tell the instruments apart without looking?
Yes, you could because the sounds instruments produce are not the same.

4. WHAT IS SOUND QUALITY?
The notes sound different because each instrument produces several different pitches: the fundamental and several overtones.
The result of several pitches blending together through interference is called sound quality.

5. SOUND QUALITY OF INSTRUMENTS
The difference in sound quality of instruments comes from structural differences in the instruments (what the instrument is made of and how the instrument is made).

6. 3 MAIN FAMILIES OF INSTRUMENTS
String instruments
Wind instruments
Percussion instruments

7. STRING INSTRUMENTS
How they make sounds: They produce sound when their strings vibrate after being plucked or bowed.
See Figure 2 on p. 619 for comparison of cello and electric guitar.

8. WIND INSTRUMENTS
2 types of wind instruments:
Woodwind
Brass

9. WOODWINDS

10. BRASS

11. WIND INSTRUMENTS
How wind instruments produce sound: a vibration is created at one end of its air column, and then the vibration creates standing waves in the air column.
See Figure 3 on p. 620.

12. PERCUSSION

13. PERCUSSION
How they make sounds: They produce sound when they are struck

14. MUSIC OR NOISE?
Noise is any undesired sound that includes a random mix of pitches.
Music is sound that has a pleasing quality, a definite repeated timing called rhythm and an identifiable pitch.

15. NOISE POLLUTION
When noise reaches a level that causes pain or damages the body it is called noise pollution.
Noise pollution can damage the inner ear, causing permanent hearing loss.
Noise pollution can contribute to sleeplessness, high blood pressure and stress.

16. WHITE NOISE
This is an equal mixture of all frequencies (like white light is a mixture of all colors).
White noise machines are used to calm people and help make them sleep.