measuring noise criteria with REW

**Drudge** · **10-11-08, 03:44 PM**

Is there a way to measure the noise criteria(NC15,NC20,NC25 etc.) of a room with the waterfall plots by looking at the 1/3 octave bands (63,125,250,500,1000,2000,4000,8000HZ) or do I have to take a seperate SPL reading for each band and then look at the published charts to see where my noise floor matches up to the different ratings?

**brucek** · **10-12-08, 08:06 AM**

REW doesn't calculate noise criteria, but read this post to show how to measure noise with REW.

brucek

**Drudge** · **10-12-08, 03:20 PM**

Well,what I was thinking of doing was when I lower the dB scale of the waterfall chart to around 35dB

or lower there seems to be a plateau of ringing that I was assuming was the noise floor but,I'm probably

wrong.There is a chart that shows what level in dB that each of the octave ranges should measure but not

exceed in level for each NC rating.I was going to look at the waterfall at each of those ranges and see were they match up to which NC rating.

But I didn't know if that would be a correct way,Thanks brucek

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