# Graph at high frequency



## dvenardos (Sep 27, 2008)

At higher frequency (starting around 300hz) my graph is all over the place. I am using the CFM-140 with correction file. Any idea what would cause this?


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## Wayne A. Pflughaupt (Apr 13, 2006)

It's comb filtering, due to reflections, Try 1/3-octave smoothing.

Regards,
Wayne


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## atledreier (Mar 2, 2007)

Either that or take a few readings at slightly different positions and average them.


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## dvenardos (Sep 27, 2008)

Wayne A. Pflughaupt said:


> It's comb filtering, due to reflections, Try 1/3-octave smoothing.


That did it, thanks.


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