Every one do not know the reality of sound, how the sound is created, what is the sound, mostly common man knows its just coming from somewhere while talking, throwing some heavy substances etc..
This article may explain few things about sound.
Any sound, whatever it might be, is caused by vibration of something. Without vibration there can be no sound. The vibrating body causes the air particles next to it to vibrate; those air particles, in turn, cause the particles next to them to vibrate. In this way a disturbance of the air moves out from the source of the sound and may eventually reach the ears of a listener. When we hear a sound, air vibrates against our eardrums causing them to vibrate also. These vibrations are detected and analysed by our brains. Although it is usually air that acts as the transmitting medium, sound can be transmitted by other media too, (e.g. water, building structures). Sound does not consist of air moving towards us in bulk; it travels through the air as a sound wave.
Sound Wave forms
A waveform of a signal is a graphical representation of its amplitude versus time at a given instant. Imagine you are in the water after the rock has been dropped. If you took a picture of the water from within the water- that is to say, a cross-section of the water, that would pretty much be a graphical representation of the amplitude (in this case, distance) of the water versus distance (one side of the picture would be closer to the rock's ground-zero), which can easily be translated into time. There's your waveform, drawn by water.
There are many forms of sound, mainly i have to explain about the noise, what is it? Lets have a look.
Noise may be defined as an unwanted sound.
A sound engineer is concerned with two sorts of noise
1. System noise, introduced by microphones, amplifiers, tape recorders, etc.
2. Ambient noise in a hall, studio, room, etc.
A sound engineer is also concerned with resonance. All objects that can be made to vibrate have a certain frequency at which they will vibrate most strongly (ie. with maximum amplitude). If a body is excited with a whole range of frequencies it will vibrate approximately equally in response to them all except those frequencies nearest to its own natural frequency. At one frequency it will vibrate most strongly. This frequency is called the resonant frequency and the condition is called resonance. A string of a musical instrument will vibrate at one frequency, its resonant frequency, whether the string is plucked, bowed or struck. Air particles have mass so any enclosed body of air (eg. the pipe or "tube" of a clarinet) has a resonant frequency. The air contained in a hall or studio can have resonance too, resulting in certain sounds being unduly emphasized.
There is also a way to remove noise, Lets we look it.
Noise cannot be removed, but it can be reduced to get the better output. Mostly many of the audio editors are have this command, some of the best tools to remove noise is FX audio editor, Gold Wave, FlexiMusic Wave Editor
Sound is playing an important role in this modern world. For examples recording an interview, conversation etc...If the noise appears we donot feel like hearing it, but our modern technlogy gives us good audio editors to be free from noise.
We have to know the reality of sound and its nature and to utilize the advanced features of good audio editor to get the better sound.