Lowpass Filter

input file : source soundfile

output file : destination soundfile (when marked)
or result.wav (for unregistered files)

processing mode : local or global

The lowpass filter (low-frequency shelving filter) can be used to attenuate the high-frequency components of the signal. The filter has two adjustable parameters.

The cutoff frequency (expressed in hertz) determines the passband of the filter, i.e. the frequency range [0 Hz,cutoff frequency] in which the signal is (almost) not modified. The cutoff frequency must be in the range [20 Hz , 0.45(sampling frequency)]

The bandpass attenuation coefficient (expressed in decibels per octave) decides upon the 'sharpness' of the filter - the larger the value of this coefficient, the steeper becomes the 'cut' at the cutoff frequency. Sharper filters are more complex, and hence they result in longer processing times.

Linear phase filtering

Previewing results of filtering

Local filtering