QA403 not doing frequency response

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I cannot get my QA403 to do frequency response. I did it once when I first got it but somehow lost the magic.

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Hi @BrotherTheo,

is it possible you don’t have a large enough FFT? In the front, you will see the annunciator “FFT Too Small” if that is the case, and nothing will show. For a 48K sample rate, you need an FFT size of at least 32k.

Please report back if that is the issue. Thanks!

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I have traced this to a different issue: the hardware seems to be locking up. After running for a while the run button turns off and will not turn on. Power cycling is needed to get it going again. What is goping on?

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Hi @BrotherTheo,

The Run button in the app will turn off when the link has been lost. You should also hear Windows play the USB disconnect bing-bong sound. And the lower left of the app will change from Connected to Connect the QA40x.

Are you seeing any of that?

Try this when time permits:

  1. Do a File->New Settings
  2. Plug in your QA40x.
  3. Click on the “ACQ: XX” counter in the status bar at the bottom of the app. This will zero the counter.
  4. Press space bar to start acquiring. Let the box sit still and acquire 1000 acquistions (should take a few minutes)
  5. Once you’ve hit around a thousand, gentle wiggle the usb connector at the QA40x hardware and PC and see if you can get it to drop. The aim here is toe verify your cable is solid.
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I was getting exactly the same issue. I reset the 403 and the measurement worked. But, When I did the power compression automated test the graphing was not separated. The Results graph showed all the measurements on the upper header, but the graph itself gave me one SPL line. When I tried distortion measurements I also got an anomalous line line. Not a 2nd or 3 rd order distortion graph.

I have installed the custom ASIO401 driver, and ARTA has worked for the first time. Not sure if there is a conflict. Also just went through a Windoz 10 update. REW doesn’t play nice yet, it actually doesn’t see the 403 as a sound interface at all. It did before the update.

Mark