Chapter 1. Understanding Digital Sound

Your most important musical tools are your ears, which have the ability to detect the tiny changes in air pressure that we call sound. Digital audio technology converts these changes in air pressure into electrical and numerical form and vice versa. To understand how your digital audio equipment works, it's helpful to know what sound is and how it's perceived and measured.

Essentials

Understanding Digital Sound

To fully grasp the nature of sound, you'll learn:

• How sound travels through air as vibrations

• How sound can be measured, and what it looks like in software

• How we hear pitch, loudness, and timbre

• How analog and digital circuitry capture and play back sound

• What determines the quality of digital audio, and how it's stored

Essential Terms

• Compression and rarefaction

• Amplitude and frequency

• Doppler effect

• Sine wave

• Fundamental, overtones, partials , harmonics, harmonic /inharmonic

• Phase cancellation

• Key tone, octave equivalency, interval, dissonance, beats

• Essential units: Hertz (Hz)/cycles per second (cps); decibel (dB); semitones and cents

• Transducer; analog and digital; A/D, D/A converters; sampling; sampling rate; bit depth

• Aliasing; Nyquist frequency; noise floor; signal-to-noise ratio

• Compression: lossy, lossless; interleaved/split files