WO2006076926A3 - Audio processor for narrow-spaced loudspeaker reproduction - Google Patents

Abstract

Audio processor for processing a set of input audio channels and generate a corresponding processed set of signals adapted for playback via a set of narrow-spaced loudspeakers with the purpose of providing a spatial image widening effect. The audio processor includes a cross talk canceller active only in a pre-selected frequency range, e.g. 1.5-18 kHz, and substantially in-active outside this frequency range. In addition, the audio processor includes applying substantially similar frequency weightings to the two input audio channels within the mentioned pre-selected frequency range. This frequency weighting is selected such that the processed set of signals provides a listener with a perceived timbre being substantially the same as a perceived timbre provided by the input set of audio signals. The frequency weighting is preferably based on a magnitude of an ipsi-lateral or a contra-lateral transfer function, or based on a square root of sum of squares of magnitudes of ipsi-lateral and contral-lateral transfer functions. The audio processor is advantageous since it provides a high sound quality without severe tonal coloration and with a stable spatial widening effect tolerant to listener head movements in spite of very narrow-spaced loudspeakers, such as with a listening angle of 4° or less, e.g. in a mobile phone or other handheld devices. In addition, the processor is advantageous in that it provides a high reproduction quality of both timbre and spatial aspects for normal stereo signals as well as binaural signals, including 3D spatial content in case of binaural input signals, without the need to adapt the processing to the actual input signal type.