kVolumeDbExpNegative
db = db * (pow(fabs(kVolumeDbMin), (1.0 / kVolumeDbExpNegative))
db = pow(db, kVolumeDbExpNegative);
db = pow(db, (1.0 / kVolumeDbExpNegative));
(1.0 / kVolumeDbExpNegative)));