Figure 2: Mean ear canal SPL output for the proprietary fitting (experienced user, bilateral fitting) of five leading manufacturers for a mild-to-moderate downward sloping hearing loss. Data shown for inputs of 55 dB (2a), 65 dB (2b), and 75 dB (2c) SPL. The NAL-NL2 targets are displayed as reference. Adapted from Sanders et al. [22].