Frequency discrimination thresholds rise dramatically from 500 Hz to 5000 Hz

Evidence

This demonstration illustrates the dependence of just-noticeable variation in frequency on the frequency of pure tones. First, a series of frequency modulated 500 Hz tones are played with frequency variations of 100, 30, 10, 3, and 1 Hz. The modulation of the first three sounds should be clearly audible. In a second series of modulated tones at 5000 Hz, again frequency variations of 100, 30, 10, 3, and 1 Hz were chosen. However, now only the first modulation is clearly audible, whereas the rest is at or below the threshold of just-noticable variation in frequency. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 3307

Our hearing system is most sensitive for sinusoidal frequency modulations at frequencies of modulation in the neighbourhood of 4 Hz. Therefore, we shall concentrate first on data related to that modulation frequency. The just-noticeable value, 2L1f, is given in Fig. 7.8 as a function of carrier frequency. The parameters are the frequency of modulation (4 Hz) and the loudness level of the frequency-modulated tones (60 phon). At low frequencies, 2L1f is approximately constant and, averaged over many subjects, has a value of about 3.6 Hz. Above about 500 Hz, 2L1f increases nearly in proportion to frequency; in this range, 2L1f is approximately 0.007 f. This means that a change in frequency of about 0.7% is just noticeable in this frequency range. At low frequencies, the relative just-noticeable change increases and has a value of 3.6% at 100 Hz. This means that at 50 Hz, 2L1f corresponds to a semi-tone in music; our hearing system is relatively insensitive for changes in the frequency of sinusoidal tones in this low-frequency range. Musical tones, however, are rarely sinusoidal tones; they comprise many harmonic components and the frequency changes of these high-frequency harmonics can be more easily detected than frequency changes of the fundamental. Thus we usually listen to higher frequency harmonics when tuning a musical instrument. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1056

Categorization

• XREF: Demonstrates the classic Weber-fraction-in-frequency finding central to psychoacoustics.
• corroborated: 2 independent passages support this claim — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 3307; Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1056