Patent ID: 9712127
Date: 2017-07-18
CPC Classifications: G01R,H03G,H04R,H04S

Claim:
1. A method of processing an A-weighted input audio signal comprising: using a circuit device including a root mean square value (RMS) level detector to provide spectral expansion of the A-weighted input audio signal by: introducing a delay to the A-weighted input audio signal; filtering, using a band-stop filter, selected low and high frequency components of the A-weighted input audio signal components from the delayed A-weighted input audio signal; wherein the selected low and high frequency components are low and high frequencies associated with relatively lower hearing sensitivity; adjusting the relative audio signal power values of the filtered low and high frequency components of the delayed A-weighted input audio signal based at least in part on a continuously adjusted and smoothed amplitude dependent scaling value, the scaling value determined using audio signal values of a number of samples associated with the A-weighted input audio signal and a reference value equal to a threshold of human hearing in terms of sound pressure including: creating and providing an output audio signal corresponding to the A-weighted input audio signal, the output audio signal created by combining the delayed A-weighted input audio signal with the filtered low and high frequency components having relative audio signal power values adjusted based at least in part on the scaling value, such that low and high frequency components of the output audio signal are driven so that a power ratio of bass and treble stopband signal components increases as the A-weighted input audio signal gets smaller; and wherein the delay introduced to the A-weighted input audio signal compensates for a delay related to the adjusting of relative audio signal power values.