Controls in "SPL & Phase" window are greyed out

yacob9999

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Mar 18, 2018
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I am trying to generate room corection filters for Roon software and these were the instruction in the Roon forum to identify the 'dips' in the frequency response curve that should not be boosted.

"Here is how you can use REW to find out where its safe to boost. Its called excess phase, and where the excess phase is spiky and far from zero, you should not try to boost. To get the excess phase, do this:
  1. Do sweep measurements, one on each side of the head, right outside the ear
  2. Generate minimum phase in REW (its in the controls section, button to the right).
  3. Select the GD tab (Group Delay), and check the excess phase"

However, in REW all the buttons in the controls, including "Generate minimum phase", are greyed out (screenshot attached), so I cannot even click on "Generate minimum phase". What am I doing wrong?

2018-03-19_20-12-09.jpg
 

John Mulcahy

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Apr 3, 2017
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That would typically indicate that the data has no impulse response, e.g. data from an RTA measurement or from importing a frequency response rather than from a sweep measurement.
 

yacob9999

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Mar 18, 2018
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Bingo! The instruction "Do sweep measurements" that I followed was not very precise, so I improvised with using a Log sweep from Generator, and used RTA to measure the response. I now googled for "sweep measurement in REW" and found the correct way.

Thank you!!
 
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