1. A method for frequency-lowering of audio signals for improved speech perception, comprising: receiving, by an analysis module of a device, a first audio signal; detecting, by the analysis module, one or more spectral characteristics of the first audio signal; classifying, by the analysis module, the first audio signal, based on the detected one or more spectral characteristics of the first audio signal; selecting, by a synthesis module of the device, a second audio signal from a plurality of audio signals, responsive to at least the classification of the first audio signal; and combining, by the synthesis module of the device, at least a portion of the first audio signal with the second audio signal for output.