You can repeat this same effect a couple of times if a sharper cut-off slope is desired.Īfter removing subsonic noise re-normalize your audio. Audacity's built-in High Pass Filter under the same menu - set the cut-off frequency to around 25 Hz.Audacity's built in Equalizer under the Effect menu.To remove subsonics from your track you may filter it with: First remove any DC offset in the recording using the Normalization plugin. Subsonic or low-band noise can enter your recorded audio through physical vibrations during the recording or noise from HVAC, fans etc.įrequencies below 20 Hz are 'subsonic' because the human ear is unable to perceive it as recognisable sound. If the quiet parts are difficult to understand, you can apply an EQīoost in the 2-5k Hz range after the compressor to aid diction. If a female voice is sibilant it will tend to be in Hey Generally if a male voice is sibilant it will tend to be in Boosting too much at these frequencies can make the voice sound highly sibilant and add too much sizzle. Cut Around 3-5 kHz if the Voice Sounds too Sibilant Be wary of this frequency range when boosting.