What is Sound ? - The Basics

What is Sound ?

All sound that we hear are sound pressure variations A speaker re produces these variations and a microphone captures these variations. Just as out Ear Captures Sound and our vocal cord Produces Sound.

When a Sound is created it creates various sound waves . Like a typical wave (you would see when you throw a stone onto a lake) , it creates ripples with Low and High Pressure . This repeating Low and High Pressure is called a sound wave.

This Sound Wave Can be categorised into three main elements

Frequency | Amplitude | Phase

Frequency :

The rate of the wave is called the frequency. Frequency is measured in how many times a cycle of high to low pressure occurs per second and is measured in Hertz. If a Guitar String Vibrates at 440 Cycles Per Second. The frequency equivalent would be 440 Hz.

Low Frequencies have Larger Cycle Lengths and Higher Frequencies have Shorter Frequency Lengths.For Eg. A Frequency of 20 HZ will have only 20 Cycles Per Second . So the Low and High Pressure Points will be Spread across Longer. A Frequency of 20 Khz (20,000Hz) will have 20,000 Cycles Per Second . So the Low and High Pressure Points will be much shorter.

Amplitude : The intensity of the wave is called the amplitude, we hear this as loudness and often describe it as volume. A common measurement of Intensity is Decibels (dB)

Phase : is the time that the wave starts compared to other waves. In a scenario where you have two microphones capturing one sound source. sometimes due to bad microphone placement and other factors the sound waves reaching one microphone can be delayed This will result in what is called "phase cancelation". This Phenomenon will result in a vey flat and dull sound.

We will look in depth about what phase is in an another article! .