Patent ID: 8150067

Claim:
A bass enhancing method comprising: detecting an envelope of an absolute value of an audio signal; and amplifying a bass component of the audio signal by a gain calculated from an envelope value so as to enhance the bass component of the audio signal, wherein the act of detecting is performed with respect to each sample of a plurality of samples of the audio signal sampled at a predetermined sampling frequency, and the act of detecting comprises: (a) if the absolute value of a current sample is greater than or equal to a previous envelope value of an immediately preceding sample, a count value C indicating a number of samples is set to zero, while a current envelope value of the current sample is made greater than the previous envelope value at the immediately preceding sample; (b) if the absolute value of the current sample is smaller than the previous envelope value at the immediately preceding sample and the count value C does not reach a predetermined number N, the count value C is incremented by one and the current envelope value at the current sample is held at the previous envelope value at the immediately preceding sample; and (c) if the absolute value of the current sample is smaller than the previous envelope value at the immediately preceding sample and the count value C reaches the predetermined number N, the current envelope value at the current sample is made smaller than the previous envelope value at the immediately preceding sample.