Chapter 21 – The Nature Chapter 21 – The Nature of Soundof Sound

Section 4 – Sound QualitySection 4 – Sound Quality

pp. 618 - 621pp. 618 - 621

TERMS TO LEARNTERMS TO LEARN

•Sound quality – Sound quality – the result of the result of several pitches blending several pitches blending together through interferencetogether through interference

•Noise – Noise – an undesired soundan undesired sound

WHAT IS SOUND QUALITY?WHAT IS SOUND QUALITY?

• If the same note is played with the If the same note is played with the same loudness on two different same loudness on two different instruments, could you tell the instruments, could you tell the instruments apart without looking? instruments apart without looking?

• Yes, you could because the sounds Yes, you could because the sounds instruments produce are not the instruments produce are not the same.same.

WHAT IS SOUND QUALITY?WHAT IS SOUND QUALITY?

• The notes sound different because The notes sound different because each instrument produces several each instrument produces several different pitches: the fundamental different pitches: the fundamental and several overtones.and several overtones.

• The result of several pitches blending The result of several pitches blending together through interference is together through interference is called called sound quality.sound quality.

SOUND QUALITY OF SOUND QUALITY OF INSTRUMENTSINSTRUMENTS

•The difference in sound The difference in sound quality of instruments comes quality of instruments comes from structural differences in from structural differences in the instruments (the instruments (what the what the instrument is made of and instrument is made of and how the instrument is madehow the instrument is made).).

3 MAIN FAMILIES OF 3 MAIN FAMILIES OF INSTRUMENTSINSTRUMENTS

•String instrumentsString instruments

•Wind instrumentsWind instruments

•Percussion instrumentsPercussion instruments

STRING INSTRUMENTSSTRING INSTRUMENTS

STRING INSTRUMENTSSTRING INSTRUMENTS

• How they make sounds: How they make sounds: They produce sound They produce sound when their strings vibrate after being plucked or when their strings vibrate after being plucked or bowed.bowed.

• See Figure 2 on p. 619 for comparison of cello See Figure 2 on p. 619 for comparison of cello and electric guitar.and electric guitar.

WIND INSTRUMENTSWIND INSTRUMENTS

•2 types of wind instruments:2 types of wind instruments:

– WoodwindWoodwind

– BrassBrass

WOODWINDSWOODWINDS

BRASSBRASS

WIND INSTRUMENTSWIND INSTRUMENTS

•How wind instruments produce How wind instruments produce sound: sound: a vibration is created at a vibration is created at one end of its air column, and one end of its air column, and then the vibration creates then the vibration creates standing waves in the air standing waves in the air columncolumn..

•See Figure 3 on p. 620.See Figure 3 on p. 620.

PERCUSSIONPERCUSSION

PERCUSSIONPERCUSSION

•How they make sounds: How they make sounds: They They produce sound when they are produce sound when they are struckstruck

MUSIC OR NOISE?MUSIC OR NOISE?

•Noise is Noise is any undesired sound any undesired sound that includes a random mix of that includes a random mix of pitches.pitches.

•Music is Music is sound that has a sound that has a pleasing quality, a definite pleasing quality, a definite repeated timing called rhythm repeated timing called rhythm and an identifiable pitch.and an identifiable pitch.

NOISE POLLUTIONNOISE POLLUTION

• When noise reaches a level that When noise reaches a level that causes pain or damages the body it causes pain or damages the body it is called is called noise pollution.noise pollution.

• Noise pollution can damage Noise pollution can damage the inner the inner earear, , causing permanent hearing losscausing permanent hearing loss..

• Noise pollution can contribute to Noise pollution can contribute to sleeplessness, high blood pressure sleeplessness, high blood pressure and stressand stress..

WHITE NOISEWHITE NOISE

• This is an equal mixture of all This is an equal mixture of all frequenciesfrequencies (like white light is a (like white light is a mixture of all colors).mixture of all colors).

• White noise machines are used White noise machines are used to to calm people and help make them calm people and help make them sleepsleep..