18. Electronics

This chapter explains a few electronic devices used in sound recording and reproduction. Concepts needed to explain the function of these devices were introduced in the previous chapter.

There is no way to record, transmit and replay sounds perfectly so that they sound exactly as they were heard originally. All recording processes fail to capture all of the audio frequencies present when the original sound was made. Microphones have limited ranges of sensitivity as do speakers and amplifying systems. These problems are called distortion and are discussed below. The problems of sound reproduction are further complicated by the fact that all the devices involved in recording, transmitting and reproducing sound add unwanted frequencies called noise. Noise can generally be defined as a sample (electronic or sound) which contains some of all frequencies. The amount of each range of frequencies present determines the color of the noise. Here are Wikipedia pages on different colors of noise: white noisepink noiseBrownian noise, Grey noise.

Samples of noise with various filters.

Key Terms:

Noise, speakers (magnetic, electrostatic, tweeter, bass), microphones (dynamic-3 types: electrostatic, piezoelectric, carbon), vinyl, magnetic tape, analog, analog to digital, digital to analog, binary number system, sample rate, bit rate, digital recording (divots, CD, DVD, Blu-ray), audio compression, lossless, lossy, MPEG3, AM, FM, digital, distortion (amplitude, harmonic, frequency, phase), MIDI.