Physics of Music
Music is an element common to all known cultures around the world. Still, it is beyond an exact definition. We are aware of the fact that music is primarily sound but, what seems curious is that all sounds are not music. It is an arrangement of sounds to generate rhythm, melody or harmony.
Physics of music is the physics of waves. Sound is a wave that travels through a medium and a medium only as the particles in the medium vibrates. They are longitudinal waves which travel in the direction of vibration of the particles. The region where particles are closest is a Compression and Rarefaction is where they are furthest apart.
These particles vibrate about a mean position. The maximum displacement of these particles from their mean position is termed as their Amplitude. Sound with larger amplitudes will be much more intense or loud than those with smaller amplitudes.
The frequency of a sound wave is the number of vibrations of particles in one second. It is measured in the unit Hertz (Hz). Sounds with higher frequencies are found to be sharp. An adult male voice has a frequency ranging from 85 to 155 Hz and that of a female is from 165 to 255 Hz. This explains why the female voice is sharper than male voice.
The distance between consecutive high pressure areas or consecutive low pressure areas is called its Wavelength. Frequency and wavelength of sound are inversely related.
Every body vibrates with its natural frequency. But, waves of frequencies which are multiples of its natural frequency are also produced. They are termed as overtones. Overtones are harmonics with frequencies greater than that of the fundamental frequency or the lowest pitch. Tuning fork is an instrument with least number of overtones and hence where used to tune musical instruments.
Perception of Music
Amplitude of a sound is perceived as its loudness whereas frequency is perceived as the sharpness of the sound. The vibration produced reaches the outer ear, travels through the ear canal and vibrates the eardrum. These are carried to the brain by the nerves and we hear the sound. Humans detect sound within the range 20 Hz to 20 kHz. It is called the Audible frequency range.
All musical instruments produce the sound we enjoy, by allowing the matter to vibrate. In string instruments , strings are fixed so as to vibrate according to certain specific frequencies. Whereas in wind instruments, the air column is made to vibrate producing sound. Membranes are used to create sounds in percussion instruments.
Read more : Magnetism
Check your knowledge
An adult male voice has a frequency ranging from 85 to 155 Hz.
The maximum displacement of these particles from their mean position is termed as their Amplitude.
The frequency of a sound wave is the number of vibrations of particles in one second.