The Low Shelf filter works on the low frequencies of the audio signal (20 Hz to 1 kHz). By specifying a frequency for the low EQ, you set the low-shelf frequency. All frequencies below the low-shelf frequency are boosted or attenuated, depending on the gain setting (-24 to +24 dB). The default low-shelf frequency setting is 80 Hz with a gain of 0 dB.

The following diagram illustrates the result of boosting gain around the specified frequency of 500 Hz using a Low Shelf filter.

The following diagram illustrates the result of limiting gain around the specified frequency of 500 Hz using a Low Shelf filter.