In the previous paragraph we saw how the flow of atmospheric pressure in relation to the active loudspeaker can be visualized as a waveform. Waveforms can actually be very complicated, but fortunately every single one of them, and I mean every single one, can be considered as an extension of a very simple wave form: the sinusoid

This is perhaps the most important part in order to fully understand the nature of sound. A mathematical approach to this subject can become extremely complicated , so in our case it will suffice to hint at the main concepts leaving out the kind of detail one would expect perhaps in the scientific field.