Trying to match RTA on REW+uMik with NTI device

dib

Registered
Thread Starter
Joined
Feb 18, 2020
Messages
2
I have an NTI Audio XL2 with a MA220 mic, and am trying to match the SPL RTA measurements in REW with a uMik-1. The broadband SPL measurements are pretty close to each other, but the 3rd octave measurements are quite far off, particularly in the higher bands (up to 10dB at 20kHz).

Here's my setup:

NTI: RTA analyser, 3rd octave bands, Z weighting, live (slow setting), Hann window
REW: RTA 1/3 octave, no smoothing, Z weighting (dB), No averaging, Hann window

The mic capsules are as close as I can get them. I would expect a small difference between the measurements, but up to 10dB at 20kHz seems to suggest there is a mismatch in the setup. Just wondered if anyone has any ideas of what to check?

Also, I ideally want to take LeqZ 30 second measurements in REW. It looks like I can do this in the SPL window, but I can't see if it's possible in the RTA window. Any help would be much appreciated. Thanks
 

John Mulcahy

REW Author
Joined
Apr 3, 2017
Messages
7,212
There are 1 minute and 10 minute Leq figures in the SPL logger, there isn't a 30 second figure.

Differences in the RTA figures are likely to be due to differing mic responses, assuming no special adjustments are being applied such as diffuse field corrections.
 

dib

Registered
Thread Starter
Joined
Feb 18, 2020
Messages
2
There are 1 minute and 10 minute Leq figures in the SPL logger, there isn't a 30 second figure.

Is this only available for broadband SPL, or is there also an option to get Leq figures in 3rd octave bands?

Differences in the RTA figures are likely to be due to differing mic responses, assuming no special adjustments are being applied such as diffuse field corrections.

I would expect a small difference due to the mic responses, but I'm using calibrated mics (using the umik calibration file in REW) so 10dB seems like quite a large difference. Not sure about special adjustments - there aren't any on the NTI or REW settings as far as I can tell.

Thanks again
 
Top Bottom