Relative Excitation Features, in all conditions, are far superior to conventional acoustic features like Mel-Frequency Cepstrum (MFC) and Perceptual Linear Prediction (PLP), and provide much more speaker-independence, channel-independence, and noise-immunity. Relative Excitation features are radically different than conventional acoustic features. Relative Excitation method doesn't try to model the speech-production or vocal tract shape, doesn't try to do deconvolution, and doesn't utilize LP (Linear Prediction) and Cepstrum techniques. This new feature set is completely related to human hearing. The present invention is inspired by the fact that human auditory perception analyzes and tracks the relations between spectral frequency component amplitudes and the “Relative Excitation” name implies relative excitation levels of human auditory neurons. Described herein is a major breakthrough for explaining and simulating the human auditory perception and its robustness.