With Fixed Expansion, the amount of reduction for low-level background noise is the same at all frequencies, regardless of the patient’s hearing loss.
Gain-Dependent Expansion
Gain-Dependent Expansion automatically adjusts how much amplification is applied in each frequency for soft environmental noise based on the overall amplification prescribed for the patient.
At frequencies where hearing loss is mild, less amplification is applied to reduce low-level noise that might be audible with better hearing. When the hearing loss is more severe, more amplification is applied to maintain environmental awareness.
