The High Shelf filter works on the high frequencies of the audio signal (1 to 20 kHz). The High Shelf filter is useful for adding crispness to the sound. By specifying a frequency for the high EQ, you set the high shelf frequency. All frequencies above the specified frequency are boosted or attenuated, depending on the gain setting (-24 to +24 dB). The default high shelf frequency setting is 12 kHz with a gain of 0 dB.
The following diagram illustrates the result of boosting gain around the specified frequency of 10 kHz using the High Shelf filter.
The following diagram illustrates the result of attenuating gain around the specified frequency of 10 kHz using the High Shelf filter.