# Shelf Filter

From Audacity Development Manual
Shelf Filter a shelf filter curve is flat at both ends rather than flat only at the frequencies being passed.

- Use these filters when you do not want to reduce the lowest bass or highest treble frequencies as much as you would with a standard high pass or low pass filter.
- Or if you actually want to boost either the low or high frequencies respectively.

| Note carefully that when you apply an effect to a time-stretched clip the changed speed of the clip will be automatically rendered. If you apply an effect to a selection within a time-stretched clip then Audacity will split the original clip so that the selection can be rendered as part of applying the effect.

| If you apply this effect with an envelope present then there is a bug whereby the envelope is removed and the audio reverts to its full amplitude state prior to the effect being applied.

  Accessed by: Effect > EQ and Filters > Shelf Filter

## Filter type

This shelf filter has a constant filter slope of 6dB per octave.

Two options are available:

- Low Shelf: to boost or cut low frequencies.
- High Shelf: to boost or cut high frequencies.

## Frequency (Hz)

The "filter frequency" is the mid-point of the filter slope. This is also known as the center frequency, or half gain frequency.

## Amount (dB)

The maximum amount of boost or reduction that will be applied. Negative amounts represent a reduction.

## Links

|< Index of Effects, Generators and Analyzers

|< Effect Menu