The Reverb Gain HF property further tweaks reflected sound by attenuating it at high frequencies. It controls a low-pass filter that applies globally to the reflected sound of all sound sources feeding the particular instance of the reverb effect. Ranges from 1.0f (0db) (no filter) to 0.0f (-100db) (virtually no reflected sound) are accepted. Units: Linear gain Range [0.0f .. 1.0f] Default: 0.89f