How to Create Audio Filters with the Equalizer

Using filters in audio is a way to eliminate certain frequency ranges from the input. We will show you how to create the three most popular filters in the equalizer, these are:

  • Low-pass filter
  • High-pass filter
  • Band-pass filter

Low-pass filter (LPF)

Frequencies 250 Hz and above are at -12dB

When applying a low-pass filter to a song, only the frequencies below the cutoff frequency will be heard. The bass of a song produce the frequencies up to around 250 Hz. Therefore when using 250 Hz as the cutoff frequency as in the picture above, only the bass of the song will remain while the rest of the song is silent.


High-pass filter (HPF)

Frequencies 250 Hz and below are at -12dB

When applying a high-pass filter to a song, only the frequencies above the cutoff frequency will be heard. Using a high pass filter is useful for removing the bass of a song. It can also be used for removing some background noise from recordings. In the example pictured above we wanted to only remove the bass from a song. Therefore, we use 250 Hz as the cutoff frequency just like we did for the low pass filter (since the bass usually goes up to 250 Hz).


Band-pass filter (BPF)

Frequencies 250 Hz and below, and 8000 Hz and above are at -12dB

When applying a band-pass filter to a song, the lower and the upper cutoff frequency creates a range of frequencies that will be passed. The frequencies outside this range will be rejected. In the example pictured above we have created a band-pass filter with a lower cut off frequency of 250 Hz and a higher cut off frequency of 8000 Hz. This will make it sound like the song is being played back from a very old device.


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Last updated: 2019-06-11