Add a volume to an waveform.
transform_vol(gain, gain_type = "amplitude")
(float): Interpreted according to the given gain_type:
gain is a positive amplitude ratio.
gain is a power (voltage squared).
gain is in decibels.
(str, optional): Type of gain. One of:
Tensor: Tensor of audio of dimension (..., time).
forward param: waveform (Tensor): Tensor of audio of dimension (..., time).