Patent ID: 7024259

Claim:
A system for evaluating the quality of an audio test signal derived from an audio reference signal by coding and decoding, said audio test signal and said audio reference signal each comprising a plurality of channels, each channel being adapted to be made audible by one loudspeaker of a plurality of loudspeakers which are positioned at different positions in an at least fictitious room, and two listening reference points being defined with respect to the positions of the plurality of loudspeakers, said system comprising: a unit for converting the audio reference signal into a first audio reference sum signal at the first reference point and into a second audio reference sum signal at the second reference point and for converting the audio test signal into a first audio test sum signal at the first reference point and into a second audio test sum signal at the second reference point, wherein the first and the second reference points are different from each other, wherein the unit for converting includes: a weighting device for weighting each channel using a respective transfer function between the respective loudspeaker and the reference point in question to obtain weighted channels, and an adding device for each reference point, the adding device for the first reference point being adapted to add weighted channels generated using transfer functions between the loudspeakers and the first reference point, and the adding device for the second reference point being adapted to add weighted channels generated using transfer functions between the loudspeakers and the second reference point so as to obtain an audio reference sum signal and an audio test sum signal for each reference point; and a unit for evaluating the quality of the audio test sum signals output by the adding devices while taking into consideration the audio reference sum signals output by the adding devices so as to provide an indication of the quality of the audio test signal.