WaveformA waveform is the shape and form of a signal such as a wave moving in a physical medium or an abstract representation.
In many cases the medium in which the wave is being propagated does not permit a direct visual image of the form. There are instruments such as an oscilloscope which can be used to represent a wave as a repeating image on a screen. The aspect of evenly spaced waves that really affects music theory is the spacing between the waves, the distance between one high point and the next. This is the wavelength and it affects the pitch of the sound the closer together the waves the higher the sound. All waves are traveling at about the same speed, the speed of sound. So waves with a shorter wavelength arrive at your ear more often (frequently) than longer waves. This aspect of sound is called frequency by scientists and engineers. They measure it in hertz, which is how many peaks go by per second. People can hear sound from about 20 - 20,000 hertz and can be effectively broken down into seven different frequency bands, with each having a different impact on the total sound. The seven frequency bands from low to high are: Sub-bass > Bass > Low midrange > Midrange >Upper midrange > Presence and Brilliance. The word musician’s use for frequency is Pitch. The shorter the wavelength, the higher the frequency and the higher the pitch. Instead of using frequencies, musicians use notes. Amplitude is the size of the vibration, and this determines how loud the sound is. Noise is measured in units called decibels, on a scale from zero to 140. The higher the number in decibels, the louder the noise, the louder the noise the greater the risk of hearing loss. No more than 15 minutes of unprotected exposure to 100 decibels is recommended. Long-term exposure to 80-85 decibels or over can cause hearing loss. Sound generator is a vibrating object that produces sound waves there are two main types of sound generator the first kind is simple and is called a vibrating or oscillating piston examples include the soundboard of a piano the surfaces of drums and symbols and a diaphragm of a loud speaker. The second kind of generator uses air pressure and is utilized by wind instruments, the opening and closing of valves within the instrument will increase or decrease atmospheric pressure thus a cycle is produced this happens very quickly in vibration of lips .i.e. and the mentioned valve. the most commonly used sound generator and one that everyone recognizes is the loudspeaker the diaphragm vibrates due to the magnetic forces and the permanent magnet that move the coil that is attached to the diaphragm. The electromagnet (coil) is positioned in a constant magnetic field created by the permanent magnet (solid). These two magnets interact with each other when an alternating current is applied. When the coil moves it pushes and pulls on the speaker coil this vibrates the air in front of the speaker creating a sound wave. |
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