1. An audio classification system comprising: at least one device operable in at least two modes requiring different resources; and a complexity controller which determines a combination and instructs the at least one device to operate according to the combination, wherein for each of the at least one device, the combination specifies one of the modes of the device, and the resources requirement of the combination does not exceed maximum available resources, wherein the at least one device comprises at least one of the following: a pre-processor for adapting an audio signal to the audio classification system; a feature extractor for extracting audio features from segments of the audio signal; a classification device for classifying the segments with a trained model based on the extracted audio features; and a post processor for smoothing the audio types of the segments.