Galaxy CM-140 C-Weighting in REW question

[Dent]

I see that the calibration file for the Galaxy SPL meter covers the range from 5 Hz up to 200 Hz. Now why has it been recommended to uncheck C-Weighting in REW? If doing our usual subwoofer response testing with REW (i.e. sweep from 0 Hz to 200 Hz), wouldn't we get the same result whether the C-Weighting in REW was checked or unchecked since I thought REW does not apply the C-Weighting inverse compensation (when checked) within the calibration file range?

If I wanted to measure the response higher than 200 Hz, let's say up to 1000 Hz or even higher, shouldn't the C-Weighting box be checked? Since I believe that you should get the same response when testing the 0 to 200 Hz range whether the C-Weighting is checked or not (and using the Galaxy calibration file), why not just leave it checked just in case one wants to measure a bit higher than 200 Hz?

I thought I saw previous posts by Ilkka where he tested his Galaxy CM-150 meter (which apparently should have the same response as the CM-140) all the way up to 20000 Hz or beyond and it was pretty close to his full range calibrated microphone. Again, if testing response up to 20000 Hz with the CM-140, the C-Weighting should be checked, right? When Ilkka did his testing with his CM-150 was there inverse C-Weighting compensation used?

Sonnie, when you were testing the CM-140 against your calibrated mic, how close was the response from 200 Hz up to 20000 Hz?

[brucek]

Now why has it been recommended to uncheck C-Weighting in REW?

Previous versions of REW created the need for this recommendation when measuring to 200Hz. The C-Weight check box extended the area below the file end point (for the Galaxy from 5Hz down to 0Hz), such that it produced erroneous results. The latest version corrected this problem.

If I wanted to measure the response higher than 200 Hz, let's say up to 1000 Hz or even higher, shouldn't the C-Weighting box be checked?

Would make no real difference with this version of REW.

why not just leave it checked just in case one wants to measure a bit higher than 200 Hz?

Fine.

Again, if testing response up to 20000 Hz with the CM-140, the C-Weighting should be checked, right?

Yep.

when you were testing the CM-140 against your calibrated mic, how close was the response from 200 Hz up to 20000 Hz?

We only tested and created a file up to 200Hz. You can't calibrate microphones against each other higher than that and obtain any accuracy. They must be sent for proper calibration.

brucek