Automatic Volume and Equalization Control in Mobile Devices

Noise spectrum and level are changed dynamically in mobile environments. Speaker volume comfortable in quite conditions becomes too low when the ambient noise level increases significantly. Speaker volume adjusted for good intelligibility in high ambient noise becomes annoyingly loud in quite. Automatic Volume Control may compensate for different levels of ambient noise by increasing or decreasing the speaker gain accordingly. However, if the noise and sound spectra are very different, such simple gain adjustment may not work well. Instead, more advanced technology will dynamically equalize reproduced sound so that it exceeds the noise level by a defined amount all over the frequency range.This paper describes practical aspects for Automatic Volume and Equalization Control in mobile audio and communication devices.