* SonarPowerNoise: WIP
* don't allow highpass > lowpass
* fix filter unit gain
The filter was computed as an amplitude gain map. This change computes energy
gains instead. This makes easier to ensure unit-gain and makes the alpha values
more in line with literature where the power spectrum is obeying the power law.
new alpha = old alpha / 2
Also fixes the gain of common_mode.
* allow stretch < 1.0, paramter range fixes
* rename lowpass/highpass to min_freq/max_freq
* remove torch.no_grad wrappers
* add previews
* static seed for previews
* README: SonarPowerNoise documentation
elias-gaeros
52f929d54d