The present disclosure relates to audio signal processing apparatuses, methods, and programs, and more specifically, to an audio signal processing apparatus, method, and program that obtain higher quality sound.
The recent size reduction of mobile devices such as notebook personal computers (PCs) often causes resonance during sound reproduction. This is because a speaker is positioned inevitably close to other components including a substrate, a keyboard, or others, or the components themselves are already smaller in size or thinner in width.
However, because taking tangible measures against resonance takes cost, such measures may be taken only within the constraints of cost, or resonance may be involuntarily accepted. As a result, the sound quality suffers.
As other measures against resonance, the sound volume may be reduced as a whole not to cause resonance. If this is the case, however, sound from some sources may be reduced too much and become inaudible, or the resulting sound may not be of satisfactory quality. In consideration thereof, there is a technology proposed to reduce resonance by reducing a gain in a resonance frequency band using a notch filter or others.
When a mobile device including a small-sized speaker such as a notebook PC reproduces movie or music contents, the sound volume is known to be low as a whole.
In order to make the sound easier to listen, there are technologies of enhancing the reproduction level of an audio signal of the sound (for example, refer to Patent Application Laid-open Nos. 2012-60379 and 2012-235310). With these technologies, the reproduction level is described to be enhanced by a dynamic change of features observed in an amplitude modulation function in response to the analysis result of an input audio signal.