AUDIO FUNDAMENTALS COURSE -LESSON 01- Frequency, Wavelenght, Phase and Decibel by Tairo Arrabal

Summary

Key Points

• —Sound is defined as vibrations traveling through an elastic medium, such as air, within the human hearing range of 20 to 20,000 Hertz (cycles per second). 0:44
• —Sound propagates as waves, characterized by cyclical movements, where frequency is the number of cycles per second and the time period is the duration of one complete cycle. 5:47
• —Frequencies are categorized into low (e.g., bass, long wavelengths), mid (e.g., human voice, crucial for clarity), and high (e.g., cymbals, short wavelengths), each influencing sound's physical size and behavior. 15:44
• —Wavelength, the physical length of one sound wave, is inversely proportional to frequency; large wavelengths of low frequencies are difficult to contain, while small wavelengths of high frequencies are easily blocked. 39:31
• —Phase describes the temporal relationship between two similar sound signals, where signals in phase combine to amplify, and signals 180 degrees out of phase can cause cancellation. 75:32
• —Phase issues, often arising from multiple microphones on one source or reflections, can be corrected by inverting polarity or applying precise delays to align waveforms. 83:35
• —Amplitude determines the loudness of a sound, while the crest factor quantifies the dynamic range between peak and average (RMS) levels, impacting the perceived punch or compression of audio. 94:03
• —The decibel (dB) is a logarithmic unit used to compare sound levels, reflecting the non-linear way human ears perceive loudness, where a 3dB change represents a doubling or halving of power. 105:58
• —Absolute decibel scales, such as dBSPL for sound pressure level and dBFS for digital audio, provide standardized measurements, with 0 dBFS being the maximum undistorted level in digital systems. 118:22