Artificial neural network

An audio processing system comprising:

• an analyser configured to generate magnitude and phase representations of first and second input signals, the phase representations depending upon one or more transformations, selected from a set of transformations, between the first and second input signals and the magnitude representations being independent of the one or more transformations;
• an output configured to acquire the magnitude and phase representations of the first and second input signals and to output one or both of:
• a phase difference between phases represented by the respective phase representations, the phase difference being indicative of the one or more transformations between the first and second input signals;
• and
• one or more of the magnitude representations, the one or more magnitude representations being indicative of the first and second input signals in the absence of the transformation.

An auto-encoder comprising:

• one or more encoding layers;
• one or more representational layers;
• and
• one or more decoding layers;
• in which the one or more encoding layers, the one or more representational layers and the one or more decoding layers are configured to cooperate to provide a representation of first and second input signals at the one or more representational layers having a first component which is dependent upon one or more transformations, of a set of transformations, between the first and second input signals and a second component which is independent of the one or more transformations.