Sound Source and Intermediate Substances (Medium)
Sound sources are all objects that vibrate and produce sound propagating through the medium or intermediate substances to the ear. Sound is produced by objects that vibrate.
The things that prove that sound is produced by things that vibrate are:
The rattled end of the ruler made a sound.
At the time of screaming, if our neck held, it will feel trembling.
Strings on a guitar that are picked will vibrate and make a sound.
The skin on the drum or drum when struck seems to vibrate.
Conditions for sound
Sound Source
Objects that can produce sound are called sound sources. Examples of sound sources are various musical instruments, such as guitar, violin, piano, drum, trumpet and flute.
Intermediate Substances (Medium)
Sound waves are invisible longitudinal waves. Sound can only flow through the medium of intermediary. For example air, water, and wood. Without a medium the sound medium cannot slow down and will not be heard. According to research, solids are the best medium for sound absorption compared to liquids and gases.
Listeners
Sound can be heard when there is a listener. Humans are equipped with the senses of the ear, which is the ear as a hearing aid.
Vibrations emanate from vibrating objects, reaching our ears generally through the air in the form of waves. Since a wave that can be in the air is just a longitudinal wave, then the sound that travels through the air is always a longitudinal wave. We need to remember that longitudinal waves are transverse and horizontal that can travel through three forms of substance: solid, liquid and gas.
There are three aspects to the sound as follows:
Sound is produced by one source like another wave, sound source is vibrating object.
The energy is transferred and the source of the sound is in the form of a longitudinal wave.
Sound is detected (known) by the ear or a rapid instrument of sound waves in the air is influenced by the temperature and mass of the substance.
Sound Frequency
As a waveform, sound has a frequency. Based on its frequency, sound waves are divided into three types: audiosonic, ultrasound, and infrared.
Audible wave. Audionic waves are sound waves that are within our range of frequencies, which range in frequency between 16 Hz and 20,000 Hz.
Infrasonic wave. Infrared waves are sound waves whose frequencies are below the audiosonic wavelength, which are frequencies smaller than 16 Hz.
Ultrasonic waves. Ultrasonic waves are sound waves whose frequencies are above the audiosonic wavelength, which is frequencies greater than 20,000 Hz.
Sound reflections
In addition to experiencing rejection, the sound is reflective. The sound reflection process is similar to the light reflection process.
Sound reflective law states that:
Angle coming = corner of bounce (i = r)
The sound came, the sound of the bounce, the normal line in one of the three fields intersecting at one point.
Sound reflection law
The coming angle is the angle formed by the direction and the normal line.
The abutment angle is an angle that is shaped by the direction of the abscess and the normal line