Missing IR Window

[ernperkins]

I’m having an issue that I hope someone can diagnose. I’m attempting “Spinoroama” type measurements from 0 to 180 degrees. Everything works fine until I reach the 170 degree measurement when the frequency response deviates wildly (see 1st picture). After a little investigation I discovered in the Impulse tab that the window function is missing (actually 0) in the 170 degree measurement. See the 2nd picture for the normal IR window and the 3rd picture for the 170 degree measurement.



I’ve tried changing the IR window parameters (see 4th picture for my standard settings), letting REW automatically choose the IR window and increasing the drive level by 3 dB. I’m using REW V5.40 Beta 123 on Windows. Thanks for any help.

 

[John Mulcahy]

At extreme angles reflections can be larger than the direct sound so the window reference gets placed on the reflection. On your zero degree measurement use the Apply windows to all button.

 

[ernperkins]

At extreme angles reflections can be larger than the direct sound so the window reference gets placed on the reflection. On your zero degree measurement use the Apply windows to all button.

Thanks, that did it!