The DeHummer removes unwanted 50 Hz / 60 Hz hum from the audio. This effect is available for 5.1, stereo, or mono clip.

Reduction

Specifies the amount of reduction to apply to the hum. High values may also cut necessary audio information in the low end.

Frequency

Specifies the center frequency of the hum. Usually this will be 50 Hz in Europe and Japan, and 60 in the US and Canada. Often the frequency of the hum is not static, but will vary by +/– 5 Hz. Click the 50 Hz or 60 Hz buttons to set the respective frequency.

Filter

Specifies the number of filters to use to remove the hum. Hum is comprised not only of the fundamental frequencies of 50 or 60 Hz, but also contain harmonics with frequencies that are multiples of the fundamental (100/110 Hz, 150/160 Hz, and such). Higher values cause greater CPU usage. Adjusting this value determines the number of harmonic frequencies to filter. For example, if you choose 60 Hz as the Frequency value, and choose 4# as the Filter value, the DeHummer filters the 60 Hz frequency along with three harmonic frequencies (120 Hz, 240 Hz, and 480 Hz), for a total of four frequencies filtered, hence the value of 4#. Higher values require more processing power.