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Discussion Starter · #1 ·
Hello,

I hope it is a quick question ...
I am trying to make some measurement for my new mini-monitor that has Hypex AS2.100 (2 channels).
When I get the IR exported file it covers between 1 and 2 seconds (~130K samples).

In the Hypex software the IR graph space is limited to about 100 ms. When I load the file, all it fist is the left window before the 1st spike.

I was trying to reduce the time frame of the exported file by defining the left and window width as 10 ms and 100 ms. But the exported file is still as big as it was.

Please help.

Thanks,
- Alex
 

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Try this:
  • Back up to the original version of the exported impulse before changing the windowing
  • export it
  • pull it up in Audacity
  • trim everything from before the first movement of the impulse
  • trim enough off the tail end to make it short enough to fit
  • be sure you save it in the right format
It should work fine.
 

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Discussion Starter · #3 ·
Try this:
  • Back up to the original version of the exported impulse before changing the windowing
  • export it
  • pull it up in Audacity
  • trim everything from before the first movement of the impulse
  • trim enough off the tail end to make it short enough to fit
  • be sure you save it in the right format
It should work fine.
I apologize, I am new to REW and Audacity. Let me guess ..
1. It might be obvious, but I am a bit confused with first two steps. What is the need to get the exported file twice (export after backup of exported file)?
2. "pull it up in Audacity" means Impart as raw data from text file (should I remove the header?)

3. I tried to Import the exported (1st time) IR file as raw data into Audacity, but what I got in Audacity did not look like Impulse Response.

I do not mind reading docs and helps, but after 3 days of research I found just bits an pieces, and things do not connect to each other. Sorry, freshman complaints :)

Thanks for you help,
Alex
 

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I apologize, I am new to REW and Audacity. Let me guess ..
1. It might be obvious, but I am a bit confused with first two steps. What is the need to get the exported file twice (export after backup of exported file)?
2. "pull it up in Audacity" means Impart as raw data from text file (should I remove the header?)

3. I tried to Import the exported (1st time) IR file as raw data into Audacity, but what I got in Audacity did not look like Impulse Response.

I do not mind reading docs and helps, but after 3 days of research I found just bits an pieces, and things do not connect to each other. Sorry, freshman complaints :)

Thanks for you help,
Alex
Beg pardon, I was perhaps a bit brief and not terribly clear.
  1. Use the standard windowing settings in REW
  2. export the impulse file from REW as a .wav file, whatever its length
  3. use Audacity, a waveform editor, to import that .wav file for editing
  4. In Audacity, trim the extra time from before the beginning of the impulse; find the point where it first starts to move from zero, probably a few (5?, 10?) mS before the peak of the impulse
  5. Still in Audacity, trim the extra time from after the end of the impulse to make the overall impulse length fit the convolution device it will be used with; if the tail is still going up and down a little, trim it at a zero crossing point, where the waveform is crossing through the zero level
  6. be sure you save from Audacity in the right format, as a .wav file
 

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You were on the right track with the window settings, but tick the box on the Export Impulse Response as WAV dialog to "Apply IR Window before Export". Although the exported file will still be long it will start at the chosen left window setting.
 

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Discussion Starter · #8 ·
You were on the right track with the window settings, but tick the box on the Export Impulse Response as WAV dialog to "Apply IR Window before Export". Although the exported file will still be long it will start at the chosen left window setting.
Hi John,

Is this feature available only for WAV export?
I tried to check the checkbox, and then export as Text, but it looks like there is no effect for the Export IR as Text.

Thanks,
- Alex
 
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