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Filters within an EQ

Audio ScienceAudio EffectsFrequencies and FiltersFilters within an EQ
Updated 6/3/2026

Flat Frequency Response

The alteration in shape caused by a filter is termed its frequency response. A flat frequency response signifies no alteration in the signal's frequency content. In its default setting, an equalizer applies no gain to any frequency bands, resulting in a flat frequency response.

📷 no EQ adjustments.png

Lowpass/High Cut Filter

A lowpass filter, alternatively referred to as a high cut filter, allows lower frequencies to pass through unchanged in all scenarios. However, it often reduces the volume of higher frequencies in many situations.

📷 high cut filter.png

Even when setting the filter's cut-off frequency (highlighted in yellow) to its minimum level, the lowest frequencies continue to pass through the filter without alteration, while nearly all of the high frequencies are attenuated. The frequency range highlighted by the red triangle indicates these high frequencies unaffected by the filter.

473x193
473x193

High Pass/Low Cut Filter

A high pass filter, sometimes referred to as a low cut filter, allows the highest frequencies to pass through the filter without alteration under all conditions. However, it often reduces the volume of low frequencies in many situations.

low cut filter
low cut filter

Even when setting the filter's cut-off frequency (highlighted in yellow) to its maximum level, the highest frequencies continue to pass through the filter without alteration, while nearly all of the low frequencies are attenuated. The frequency range highlighted by the red triangle indicates these high frequencies unaffected by the filter.

high pass filter
high pass filter

Bell Filter

A bell filter enables adjustment, either amplifying or reducing a specific range of frequencies.

bell filter boost
bell filter boost

bell filter cut
bell filter cut

Notch Filter

A notch filter completely removes a frequency region from the sound.

notch filter
notch filter

Low Shelf

A low shelf filter boosts or cuts the low frequencies using a shelf-like shape.

boosting low shelf
boosting low shelf

cutting low shelf
cutting low shelf

High Shelf

A high shelf filter boosts or cuts the high frequencies using a shelf-like shape.

boosting high shelf
boosting high shelf

cutting high shelf
cutting high shelf