We hear sounds from vibrations caused in the medium such as air, causing pressure to waves to emmunate from the object to our ear drums.

The volume of the sound is determined by the intensity or the force of the push.

The pitch of the sound is determined by the frequency (i.e. the amount of wave per second)

Analog - The key is that the object vibrates continuously, producing a continuosly changing wave which is called analog information.

Analog representation (recording) - When this pressure variation is recorded directly, as it was orginally by Thomas Edison with a scratch on wax cylinder, and then later with vinyl records, we have a continuous (analog) representation of the wave. In principle, all of the continuous variation of the wave is recorded. When it is recorded it converts the continuous information into discrete information, and then this is converted to bits.

Sampling - This is the method of taking measurements at regular intervals.

Sample rate - This is the number of samples in a second. It is used to describe the faster the rate, the more accurate and the recording.

Getting the right sampling rate - If you want to get the wave of the recording correct, you will need to use sampling rate and use it right. This means knowing how to get the right rate. The 'Nyquist rule' is a guideline for sampling rate, and it says that the sampling rate has to to twice as fast as the fastest frequency. This basic guideline will prevent waves fitting between the samples.

ADC - This stands for 'Analog Digital convertor'. The conversion inputs the analog sound such as a Microphone and store it as data. DAC - This stands for 'Digital Analog convertor'. The reversion of the digital sound back to analog sound through output device such as headphone or speakers.

The advantage of digital sound is that you can listen to sounds through devices such as MP3, CD players and Media players. When you convert the sound from analog, you are also compressing the information making the data smaller so it can fit which is more desirable for people. The only downfall is that you lose some quality however it is not hearable to the human ears.