Sound measurement

[Memoklick]

I have the following measuring instruments that I have not managed to measure correctly in rew.
focusrite scarlett 4i4 3rd and mm1 mic. No matter what I do, I do not get the correct sound level, i.e. correct db level, rew keeps saying that I have too high a value therefore the measurement cannot be used as a reference, what have I missed?

 

[John Mulcahy]

You need to go through SPL calibration. The value you enter must come from your own SPL meter or app. You can turn off the SPL limit check on the Measure dialog.

 

[Memoklick]

You mean a hardware spl meter?

 

[John Mulcahy]

Yes, if you want accurate SPL figures that's the only way for REW to know how the signal from the mic corresponds to SPL. If you are only interested in the response shape you can just enter a rough figure, e.g. 75 dB.

 

[Memoklick]

Any recommendation which one ?

 

[John Mulcahy]

It depends how accurate you need the SPL to be. If you are making measurements to use for EQ just enter a vaguely reasonable figure, the actual SPL doesn't matter. If you need to measure SPL precisely e.g. for reporting event noise measurement you would need a class 1 meter to use as a reference or a class 1 mic calibrator, but the MM1 has a non-standard diameter so to use a mic calibrator you would need to source or fabricate an adaptor.

 

[dcibel]

Most measurement operations don't require accurate absolute SPL, only relative difference in SPL between various sources and measurements is needed. Calibrated SPL level becomes useful for more advanced operations, like noise level evaluation, or reference SPL levels for distortion analysis.

I use this one, it's quite nice: https://www.amazon.ca/Sound-Acoustical-Calibrator-output-levels/dp/B01FFI2OAU
It has an insert for a 1/2" mic capsule that's removable, so I designed and 3D printed inserts for my mics that are different shapes and sizes.

 

[Memoklick]

 

[Memoklick]

Are those two a good combination

 

[dcibel]

I wouldn't waste your time with a SPL meter. Once you calibrate your mic, it's a much more accurate SPL meter than most any handheld device.

Top mic calibrator is the one I recommended, so yes it's a good choice. You will need to craft an adapter for a 1/4" mic.

 

[Memoklick]

understood, can you please recommend an adapter that fits