Abstract: Methods and systems to modify an audio signal, such as a speech signal, while preserving aural distinctions between sounds of the audio signal. Methods and systems disclosed herein may be implemented with respect to cellular telephones and portable music devices, such as to reduce and/or prevent hearing loss due. Audio modification may include sweeping through one or more frequency ranges of a speech signal and modifying frequencies within the frequency range as a function of a pattern, such as an infinite rising wave pattern. Speech modification may include adding and subtracting one or more equalization curves to and from the speech signal to vary amplitudes substantially without lateral movement in pitch.