Use REW to analyze recorded acoustic noise ?

[craigctodd]

I'm going to get my car treated to reduce road noise in the cabin. I want to do before/after measurements. I'd like to use the REW RTA for that. I don't want to try and do that while also driving (duh) so I'd like to record the noise using the UMIK calibrated mike and then be able to play that recording for analysis by REW to get a calibrated spectrum plot of the noise.
So I'm wondering how to do that.
How to record the UMIK USB mic directly into a digital wav file with no processing applied?
How to use a wav file as source into the REW RTA?
Any hints/suggestions would be very welcome. Thanks.

 

[John Mulcahy]

You can record the mic with an application such as Audacity and export the recording from Audacity as a WAV file. WAV files can be dragged onto the RTA for analysis.

 

[craigctodd]

Thank's John!
I was wondering whether Audacity would record the UMIK mic bits without alteration and whether REW could work with files. I very much appreciate the quick answer.

 

[DanDan]

I was wondering whether Audacity would record the UMIK mic bits without alteration and whether REW could work with files. I very much appreciate the quick answer.
Sure, why not?

 

[craigctodd]

Re DanDan's comment:"Sure, why not?"

Well, Audacity has an input gain control and who knows what Windows might be doing.

So I did a test: ran pink noise in my listening room, got a REW RTA measurement with the mic plugged into the computer running REW. Then I made a recording from the mic using Audacity, input gain at 100%, then had REW RTA measure that file. Results were within a small fraction of a dB so I'm all set to measure my car before and after treatment for road noise.

 

[John Mulcahy]

Make sure your mic is plugged in and selected as the input when you import the file, that ensures REW uses its cal data and sensitivity information.