How to Create a Mysterious Voice Filter in Audacity
by Joe Laudato
In the anime “Death Note,” the detective known as “L” uses a voice filter to safely speak on television to a mass murderer who can inflict heart attacks to distant targets. (the filtered voice begins at 2:33)
I found that this effect is easily obtainable through a bit of pitch manipulation in Audacity. Starting out with this raw audio clip:
I first used the “Normalize” function under the “Effect” tab, setting the decibel value to -2.0 in order to augment the sound of my voice. The Normalize effect resulted in stronger peaks and troughs:
To achieve the voice filter effect, I selected the recording and duplicated it twice, pressing (CTRL + D) two times. Alternatively, you could select the recording and press “Duplicate” under the “Edit” tab twice. I then selected the top copy of the recording, and opened the “Change Pitch” effect under the “Effect” tab. I modified only the “Percent Change” value, setting it to “-15” and clicking “OK.”
Now that the top copy had been modified, I selected the bottom copy of the recording and again opened the “Change Pitch” effect, but this time I set the “Percent Change” value to positive 15 rather than negative 15. The finished product didn’t look much different in terms of the waveform, but sounded very similar to L’s voice filter.