Communication Acoustics: An Introduction to Speech, Audio and Psychoacoustics

4 Electroacoustics and Responses of Audio Systems

Electroacoustics is a topic that connects acoustics and electrical engineering. Some physical phenomena can be used to convert an electrical signal – a voltage or a current – into a sound, or vice versa. Electroacoustic devices, particularly microphones, loudspeakers, and headphones, are essential components in speech communication, audio technology, and multimedia sound. Electroacoustic devices are also important in acoustic measurements and scientific research on various aspects of sound.

Sound reproduction and processing of audio signals has developed over more than a century to a stage in engineering where many of the components in a reproduction or signal processing chain can be made practically perfect from a perceptual point of view, implying that imperfections in the reproduction cannot be noticed.

Digital signal processing in particular has improved the price/quality ratio of audio recording and playback compared to analogue techniques, practically replacing them. Analogue electronic components, such as amplifiers, can also be made practically perfect. However, some electroacoustic components of the audio reproduction chain, especially loudspeakers and their connection to room acoustics, are more problematic. Headphone reproduction is also not straightforward if a very accurate sound field inside the ear canal is desired. These issues motivate the use of signal processing to enhance the responses of audio devices. This ...