Improving percieved bass and reconstruction of high frequencies for band limited signals

Bandwidth extenstion methods are required in systems that playback bandlimited signals (e.g. telephone, MP3) or that are not capable of reproducing signals with a large bandwidth (small or inexpensive loudspeakers). The first part of this paper deals with reproducing low pitched signals through small loudspeakers. This work is based on psychoacoustic phenomena to invoke a deep bass impression using only higher frequency components. The second part of this paper deals with high-frequency bandwidth extension of music and speech. In this method, no additional information on the original wide band content is required. It aims at providing a more pleasant and brighter sound impression