_DbToGain
_DbToGain(_ExponentialToLinear(kVolumeDbMin)) * kVolumeFactor,
_DbToGain(_ExponentialToLinear(kVolumeDbMax)) * kVolumeFactor,
fVolumeSlider->SetValue(_DbToGain(_ExponentialToLinear(0.0))
float gain = _DbToGain(exponential);
float gain = _DbToGain(db);
float _DbToGain(float db);