Noise reduction can be turned on or off by selecting "Noise reduction > Noise reduction" in the menu.
The noise reduction level can be adjusted with the "Noise reduction > Reduction lvl" item in the menu. Larger values will reduce the noise more, but values that are too large will distort the signal and make it harder to understand (since some of the signal will be classified as noise and removed). A value of around 50 is often a good starting point. Values much above 80 are likely to distort speech too much, but may be useful for CW.
"Tone reduction": if this is turned on, then tones that are constant for more than a couple of seconds will also be reduced. This should be used if there are interfering constant tones in the input that cannot be removed by adjusting the bandpass filter. Otherwise, the output is often clearer with this turned off.
Discontinuous tones such as Morse code will not be removed by the tone reduction feature.
"Noise percentile": this setting is related to how the WOLFWAVE estimates the noise level in the input signal. If this is incorrect, then possible effects include:
The correct noise percentile to use depends on the passband of the input to the WOLFWAVE (i.e. the passband of the radio that is connected to the input, not the passband of the WOLFWAVE's bandpass filter).