Man's physical universe

xanabras

THE SCIENTIFIC BASIS OF MUSIC 469

When we compare the frequencies of E on the C and D scales above,

it is seen that on the C scale E is 320, while it is 324 on the D scale.

To make possible the major scale in each key would require so many

notes that musical instruments would be too complex for the average

person to play.

In order to avoid the difficulty of having two different

frequencies to represent one note,

the international or equal-tempered

scale was devised. In this scale

middle C represents a frequency of

258.7, and the frequencies for each

of the thirteen tones in each octave

are equally spaced. The equaltempered

scale produces a pitch

for each key that is not ideal for

best harmony, but the difference

between the ideal pitch and the

actual pitch can scarcely be recognized

by the human ear.

How Musical Instruments Produce

Sounds.

As already pointed out, all musical

instruments consist of two

parts: the generator and the amplifier.

The generator supplies the

energy and fixes the frequency,

while the amplifier enlarges the

sound by forced vibration or resonance.

There are two main types

of instruments: the stringed instruments and the wind instruments.

Stringed Instruments. The generator in stringed instruments consists

of strings or wires which are bowed (as in the violin), plucked (as

in the harp or violin), or struck with a hammer (as in the piano) in

order to produce the vibrations. The amplifier in such instruments

may consist of a hollow wooden body (as in the violin) or a sounding

board (as in the piano).

The different frequencies are produced in stringed instruments by

the use of strings of different length, diameter, and tension. The

heavier strings are wrapped with wire in order to provide inertia without

impairing their flexibility. The piano and the harp contain many

strings of fixed length, diameter, and tension, whereas other stringed

instruments contain only a few strings whose effective length can be

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