Alignment issues

twelti76

New Member
Thread Starter
Joined
May 30, 2019
Messages
16
I'm having trouble aligning 2 measurements. Actually I have 3 measurements. One is a nearfield meas of a subwoofer. The other two are in opposite corners of the room. One of the corner measurements aligns fine with the reference nearfield measurement, the other one not so much. The second measurement gives a very weird result after aligning and then using "A/B". The measurement causing the issue is a full BW measurement, and the other two measurements are only up to 300 Hz. So the corner measurement and the nearfield measurement, both of which have 20-300 Hz BW, align and divide fine. The other measurement which is 20-20000 Hz I cannot get to align with the nearfield measurement (20-300 Hz). I did open up the Alignment Tool and tried to use the cursor to align them below 300 Hz but cannot get alignment or a good looking curve division. I though of maybe using the Min Phase option for each measurement. I might try that. OR, if the different freq ranges are causing the issue, is there a way to truncate the full BW meas to 300 Hz and go from there?
 

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John Mulcahy

REW Author
Joined
Apr 3, 2017
Messages
7,212
There is a lot of noise in the "LR corner fl, PB 0dB" measurement, which won't be helping. It does nonetheless give a sensible result when using the front as A and that measurement as B, but the other way around, which is dividing a full range measurement by a band limited measurement, is likely to be problematic. There isn't a way to change the bandwidth of a measurement in REW, but you could export it as text, remove the file entries after 300 Hz, then re-import that truncated file.

As the measurements are in different positions you will probably get better alignments by using Estimate IR delay to remove the delays from each, but that won't fix the division problem.
 
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