Predicted (using the statistical model) difference between SLM (Sound Level Meter) and application measurements with increasing frequency for three applications: Bolden, KTW, and Keuwlsoft. Dashed lines represent Device 1, and solid lines represent Device 2 for each application. (A) Differences for a sound level of 54.4 dB. (B) Differences for a sound level of 106.9 dB. (C) Differences for pseudo-calibrated applications. (D) Differences without pseudo-calibration.