A map of periodicity orthogonal to frequency representation in the cat auditory cortex.  Gerald Langner, Ben Godde, and Hubert R. Dinse Examples of auditory stimuli. 1. 5 pure tones Pure tone frequencies are: 800 Hz 1600 Hz 3200 Hz 6400 Hz 12800 Hz 2. 15 harmonic sounds Harmonic sounds are composed of harmonics of fundamental frequencies between 50 and 1200 Hz. All harmonic sounds have an upper cut-off frequency of 4.8 kHz. Lower cut-off frequencies are 0.4, 0.8, or 1.6 kHz. cut-off frequency 0.4 kHz, fundamental frequency: 50 Hz 100 Hz 200 Hz 400 Hz cut-off frequency, 0.8 kHz, fundamental frequency: 50 Hz 100 Hz 200 Hz 400 Hz 800 Hz 1200 Hz cut-off frequency 1.6 kHz, fundamental frequency: 50 Hz 100 Hz 200 Hz 400 Hz 800 Hz 1200 Hz 3. 12 sinusoidal amplitude modulations Sinusoidal amplitude modulations have carrier frequencies of 0.8, 1.6, and 3.2 kHz and are 100% modulated by frequencies between 50 and 800 Hz, with the exception of sounds with the ratio of carrier and modulation frequency smaller than 4; they were excluded because in these cases the ear is able to resolve the sidebands of the amplitude modulations. carrier frequency 0.8 kHz, modulation frequency: 50 Hz 100 Hz 200 Hz carrier frequency 1.6 kHz, modulation frequency: 50 Hz 100 Hz 200 Hz 400 Hz carrier frequency 3.2 kHz, modulation frequency: 50 Hz 100 Hz 200 Hz 400 Hz 800 Hz 4. 5 band-pass filtered noise sounds The band-pass filtered white noise have centre frequencies between 200 Hz and 3200 Hz and bandwidths increasing in proportion from 50 to 800 Hz. Band pass filtered noise: 200 Hz 400 Hz 800 Hz 1600 Hz 3200 Hz