Sound. We hear it all around us, in the form of music (which our ears like) and noise (which they don't). You probably know what sound is, though a definition never hurt anyone: sound is the vibration of air molecules, which are transferred outwards from the source. Thus they are waves of sound (which we can’t see, only hear).
The number of times these waves move to and fro per second is called frequency; in my opinion the most important factor to understand. The normal sounds that we hear have many waves added (or subtracted), so that means each wave has a different frequency. They combine to form the music or noise that we hear. EQ is simply the equalization of the frequencies in your sound wave.
So what the heck is EQ?
There are two ways of looking at EQ. One is the important safety factor, which even the most ‘experienced’ sound engineers ignore. It’s an important factor, as the wrong EQ setting on your software or deck can give out harmful sound – it can even make you deaf in the long run. The right settings can make the music sound better, as in more pleasing and serve the purpose better.
Back to the F word, our ears are capable of hearing 20 Hz – 20KHz (Hertz is the unit to measure frequency of anything, not just sound). So as I said, any music we hear, or speech or instrument we listen to, will be a mixed sound wave comprising various ‘Hz’ of frequency, in different volumes. Sometimes low frequencies will be louder, sometime highs will be. The sound/music is ‘good’ or ‘pleasant’ when all the frequencies are well balanced, not necessarily equal in amounts, but just well balanced, known as good ‘tone’ in guitar parlance.
Piyush, i think your question refers to auditory masking.
