Virtual Bass Algorithm Based On Harmonic Control

With the advantages of small size, low power consumption, low cost, small loudspeakersare the essential unit of notebook computers, smart phones, MP3, MP4and other portablemedia devices. However, limited to the small size, small loudspeakers have poorlow-frequency capability, that cannot satisfy people on the demand for high-quality audio.Virtual bass is an effective method of improving the low-frequency capability of smallloudspeakers, that is based on the virtual pitch phenomenon.Currently, there are two mainly virtual bass algorithms: the VB Phase Vocoder algorithmand the MaxxBass algorithm. Comparing the two algorithms, VB Phase Vocoder algorithm ismore flexible and more accurate than the MaxxBass. And the VB Phase Vocoder algorithmcould effectively eliminate the nonlinear distortion. However, these algorithms have notresearch about the effects of harmonics components and the amplitude of harmonics. By theway, it does not take the masking effect into account in the loudness control unit, so thesynthetic harmonics does not equal loudness with the low-frequency component.For deficiencies in the existing virtual bass algorithm, a new algorithm is proposed callvirtual bass algorithm based on harmonics control. The new algorithm uses a better effectiveratio of harmonic amplitude, according to relationship of timbre and harmonic components.And it the loudness calculation model to control the loudness of harmonics.Obtained from the experimental results of subjective quality evaluation, the virtual basseffect of the new algorithm has improved significantly. And the quality of audio isn’tsignificantly reduced after processed.Virtual bass algorithm based on harmonic control significantly improves the playbackeffect of small loudspeakers, and enhance its bass pitch. However, there are still differencesbetween the sense of virtual bass and original bass. How to improve the "real" feel of thevirtual bass, it is worth further research.