Apple Inc.
Automatic level control for psychoacoustic bass enhancement

Abstract:

An audio electronics system operates on audio data. A low-pass or bandpass filter produces first data from audio data. A level detector produces a time-varying first gain. The first gain is based on a time-varying level of the first data. A harmonics generator receives, as input, the first data adjusted by an inverse of the first gain. The harmonics generator produces second data, as harmonics of the input. A multiplier outputs the second data adjusted by the first gain. Other aspects are also described and claimed.