1. 100 110 120 2505001000200040008000 Hz 0 10 20 30 40 50 60 70 80 90 A A A A A A 10 15 20 30 LDL for speech Aided Speech output Functional Gain: The way hearing aid gain was 1st verified Figure 1

2. * dB SPL at TM 120 Frequency 250 500 1000 2000 4000 8000 * * * * * * dB Gain 110 100 90 80 70 60 50 40 30 20 10 0 REAR REUR Target REIG Then Came Insertion Gain: Aided vs Unaided SPL at the TM Figure 2

3. * dB SPL at TM 120 Frequency * * * * * * 110 100 90 80 70 60 50 40 30 20 10 0 250 500 1000 2000 4000 8000 * * * ** * * Today we use Insitu Output: Map Soft, Average, Loud speech into remaining Dynamic Range LDL * * * Normal HL * * * Targets: Loud Average Soft Figure 3