Frequency resolution refers to the auditory system’s ability to resolve frequency components (pure tones) in a complex sound. For example, when two notes are struck on the piano we can hear two distinct tones but if they are too close the tones are heard as one tone with a beat equal to the frequency difference between the tones. The beat is caused by a physical interaction where the two tones add in-phase or out-of-phase leading to a slow variation in magnitude equal to the frequency difference of the tones.

The smallest detectable difference in frequency of a tone is 0.3% to 0.5% in the frequency range 0.5 to 6 kHz if the test tone is at a comfortable level. The detection ability is reduced for low ...