I’m asking about impulse response measurements made with REW.
Should I apply these REW window options to the measurement before import to FIR designer?
Impulse Response Window Defaults
The Left Side and Right Side window selectors offer a choice of window types to be applied to the impulse response data before and after the peak. These are the defaults applied to new measurements, window types for existing measurement can be altered via the IR Windows toolbar button. By default REW will set the widths of the windows automatically to show the whole room response, with a 500 ms right side window and a 125 ms left side window if the end frequency of the sweep is above 200 Hz, or a larger left side window for end frequencies below 200 Hz. To override this uncheck the Set window widths automatically box and set the default widths you wish to be applied to new measurements.
If Add frequency dependent window is selected a frequency dependent window (FDW) will be applied to the measurement after the left and right windows have been applied. The width of the FDW is set by the controls to the right and can be specified in cycles or in octaves. If the width is in cycles a 15 cycle window (for example) would have a width of 150 ms at 100 Hz (15 times 10 ms), 15 ms at 1 kHz (15 times 1 ms) and 1.5 ms at 10 kHz (15 times 0.1 ms).