How To Use a High-pass Filter To Increase the Clarity of a Voice

The human voice is essentially a mid-range instrument, which means that most of its information resides in the mid-range of the frequency spectrum.

Humans can hear frequencies between around 20 Hz and 20,000 Hz, and the human voice does contain information along this entire spectrum, but the vast majority of the sound (including the most important frequencies for intelligibility) resides between around 250Hz and 4kHz.

A high-pass filter reduces the volume of the lowest frequencies (usually around 60-100Hz and below); it lets “high frequencies pass” through, hence the name high-pass filter. See the EQ curve above.

Basically, when you reduce the level of the lowest frequencies in any sound source, the midrange and higher frequencies will stand out more. Therefor, generally, using a high-pass filter will increase the clarity in a persons voice. Of course you can overdo it, so don’t overdo it! HA

Finally, the HOW TO:

Use a high-pass filter (available in most EQ plugins) to reduce the lowest frequencies. Common practice is to reduce from around 60Hz and below, but sometimes you will need to reduce more, say from 80-100Hz and below. Use your ears to determine how much you should remove to make the voice more clear. But don’t remove too much or else the voice will start sounding small, wimpy, thin and possibly harsh.

FYI, here’s a very helpful and thorough technical article titled Facts About Speech Intelligibility — https://www.dpamicrophones.com/mic-university/facts-about-speech-intelligibility

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