HighPassFilter
Added in v0.18.0, updated in v0.21.0
Apply high-pass filtering to the input audio of parametrized filter steepness (6/12/18... dB / octave). Can also be set for zero-phase filtering (will result in a 6 dB drop at cutoff).
Input-output example
Here we input a high-quality speech recording and apply HighPassFilter with a cutoff
frequency of 1000 Hz, a filter roll-off of 12 dB/octave and with zero_phase=False.
One can see in the spectrogram below that the low frequencies (at the bottom)
are attenuated in the output. This change is not immediately obvious when just looking
at the spectrogram with linear frequency axis, but if you listen to the transformed sound,
you'll immediately hear that all the bass/"meat"/warmth/body is gone.
| Input sound | Transformed sound |
|---|---|
Usage example
from audiomentations import HighPassFilter
transform = HighPassFilter(min_cutoff_freq=200.0, max_cutoff_freq=1500.0, p=1.0)
augmented_sound = transform(my_waveform_ndarray, sample_rate=48000)
HighPassFilter API
min_cutoff_freq:float• unit: hertz • range: (0.0,max_cutoff_freq]- Default:
20.0. Minimum cutoff frequency max_cutoff_freq:float• unit: hertz • range: [min_cutoff_freq, sample_rate/2)- Default:
2400.0. Maximum cutoff frequency min_rolloff:float• unit: Decibels/octave- Default:
12. Minimum filter roll-off (in dB/octave). Must be a multiple of 6 (or 12 ifzero_phaseisTrue) max_rolloff:float• unit: Decibels/octave- Default:
24. Maximum filter roll-off (in dB/octave). Must be a multiple of 6 (or 12 ifzero_phaseisTrue) zero_phase:bool- Default:
False. Whether filtering should be zero phase. When this is set toTrue, it will not affect the phase of the input signal but will sound 3 dB lower at the cutoff frequency compared to the non-zero phase case (6 dB vs. 3 dB). Additionally, it is twice as slow as the non-zero phase case. If you absolutely want no phase distortions (e.g. want to augment an audio file with lots of transients, like a drum track), set this toTrue. p:float• range: [0.0, 1.0]- Default:
0.5. The probability of applying this transform.