#### Input Type

Select C Weighted SPL Meter if you are using a C weighted SPL meter as the input to REW, measurements will then be corrected to remove the low and high frequency roll-offs of the C weighting characteristic. If a cal file is loaded the correction will only be applied outside the frequency range covered by the cal file.

If you are using a microphone as the input to REW, or an SPL meter with Z weighting (which means it does not have any weighting curve applied) choose Mic or Z Weighted SPL Meter.

#### Calibration

If you have a calibration data file for your SPL meter or microphone you can load the data into REW by clicking the Browse button. The calibration data will be applied to all new measurements taken after it has been loaded and will be shown on the SPL & Phase graph for the measurements. To remove the calibration data file click the Clear Cal button.

To apply or remove a calibration file for an existing measurement, use the Change Cal... button in the measurement panel.

To calibrate the REW SPL meter reading against an external meter use the Calibrate button in the SPL Meter controls.