Masking of complex sound--technical notes for realization of constant signal-noise-ratio

Based on findings regarding unconscious semantic information-processing for meaningful visual stimuli, this paper describes a standardized procedure for the construction of constant signal to noise ratio for the masking of complex sounds. The proposed algorithm is derived from psychoacoustical laws concerning frequency and time-weighting of sound. Spectral characteristics are taken into account by mixing signal and white noise within frequency ranges defined through critical bandwidth ("narrow-band masking"). Furthermore, time-weighting is taken into account using sound-pressure patterns generated through low pass filters which follow the international specification DIN IEC 651 which provides specification for sound-level meters. Hardware and software circuits are described in detail. This proposal overcomes recognized lack of standardized methods in studies addressing unconscious semantic processing of auditory stimuli.