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Crazy REW Results
Old 2nd June 2019
  #1
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chrismeraz's Avatar
 

Crazy REW Results

REW was giving me reasonable results yesterday. Today, I get complete nonsense. What gives?





Attached Thumbnails
Crazy REW Results-spectrogram.png   Crazy REW Results-distortion.png   Crazy REW Results-filtered-ir.png  

Last edited by chrismeraz; 2nd June 2019 at 03:19 PM..
Old 2nd June 2019
  #2
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akebrake's Avatar
 

Quote:
Originally Posted by chrismeraz View Post
REW was giving me reasonable results yesterday. Today, I get complete nonsense. What gives?

Distortion is 100% ! in the low end.
THD (Total Harmonic Distortion) is as high as the Fundamental
Crazy REW Results-distortion.jpg
I guess you run into clipping somewhere in the signal chain.

Try lowering the monitor volume (if you are sweeping loud) or mic gain a and try again.

Good Luck!

PS If you upload the mdat we can have a closer look
Also the ”yesterday” mdat to compare with.
Attached Thumbnails
Crazy REW Results-distortion.jpg  
Old 3rd June 2019
  #3
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Thanks, sure, here is the combined .mdat file.

Speakers and microphone are both far from clipping.
Attached Files
File Type: mdat Yesterday and today.mdat (5.02 MB, 6 views)
Old 3rd June 2019
  #4
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Can you describe your recording chain?
Old 3rd June 2019
  #5
Gear Maniac
 

You were using UAD2 via ASIO4All on the June 1 measurements but haven't got an input/output selection for June 3, so the Windows defaults will be used. Check the REW soundcard settings and reselect the devices and inputs/outputs you are using, note that it is best to connect the device before starting REW and leave it connected until REW is closed.
Old 3rd June 2019
  #6
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Ultrasonic_UK's Avatar
 

Does it sound any different?
Old 3rd June 2019
  #7
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akebrake's Avatar
 

Thanks for chiming in John!

This kind of interface problems would have been difficult to solve without you!

Cheers
Old 4th June 2019
  #8
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Sorry guys, it isn't solved at all. :-(

I tried ASIO4ALL but the distortion and SPL and Spectrogram results are even worse, plus I get lots of random clicking sounds coming out of the speaker during the sweep. My hardware buffer size is 512.

Quote:
Originally Posted by JohnPM View Post
You were using UAD2 via ASIO4All on the June 1 measurements but haven't got an input/output selection for June 3, so the Windows defaults will be used. Check the REW soundcard settings and reselect the devices and inputs/outputs you are using, note that it is best to connect the device before starting REW and leave it connected until REW is closed.
Old 4th June 2019
  #9
Lives for gear
May be you have a re entry with a chanel defined on your soundcard routing?
Old 4th June 2019
  #10
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I don't know what you mean...

I've just reinstalled Windows, Apollo drivers, and REW. I still get the same results. I'm using the Java drivers with a 64k buffer.

The sweep sounds good coming out of the speakers, and there's no clipping on the mic input.

Quote:
Originally Posted by dinococcus View Post
May be you have a re entry with a chanel defined on your soundcard routing?
Old 4th June 2019
  #11
Gear Maniac
 

If you have ASIO drivers for the UAD2 just select them directly rather than using ASIO4All. If you are getting clicks doing that increase the buffer size, the larger the better, though 44.1k measurements wouldn't usually be a problem. Something has changed since the Jun 1 measurement. There are 2 peaks in the Jun 3 measurement impulse response, so monitoring being active could be a factor - the input signal must not be routed back to the output.
Old 4th June 2019
  #12
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Your software works fine with directsound drivers, why Asio ?
Old 4th June 2019
  #13
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Quote:
Originally Posted by chrismeraz View Post
I don't know what you mean...
two input channels on the same output in the routing configuration of the soundcard.
Old 4th June 2019
  #14
Gear Maniac
 

Quote:
Originally Posted by dinococcus View Post
Your software works fine with directsound drivers, why Asio ?
ASIO4All was used for the first measurement, if ASIO is going to be used and the input and output are on the same device best using the native ASIO driver for the device rather than a wrapper like ASIO4All.

On Windows ASIO is the only way to get sample widths greater than 16 bits, a limitation of JavaSound on Windows (I have submitted a request to Oracle to address that). Not an issue for acoustic measurements but it is a limitation for measurements of electronic equipment. It is also usually needed to access the individual channels of multichannel devices on Windows, another JavaSound on Windows limitation I have asked to be addressed. macOS JavaSound supports 24-bit data and multichannel cards using the Java drivers.

ASIO also allows sample rate selection that applies to the device itself, with the Java drivers REW asks the OS for the requested rate but the OS will resample from whatever rate the device is configured to run at in Windows.
Old 4th June 2019
  #15
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Could this red text have something to do with it?

Crazy REW Results-impedance-calibration-required.png
Attached Thumbnails
Crazy REW Results-impedance-calibration-required.png  
Old 4th June 2019
  #16
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There is no ASIO driver shown in REW for this UAD device. I have an Apollo 8 Thunderbolt. The drop-down menu shows only Apollo Twin MkII and Apollo FireWire - I tried them both by the way but they don't work at all.

I've done my best to ensure only one input and one output are being routed through the sound card. I don't even think it's possible to do otherwise.
Old 4th June 2019
  #17
Gear Maniac
 

Why is Impedance measurement selected instead of SPL measurement?
Old 4th June 2019
  #18
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I was just looking around. It's the first time I see that screen. I always do SPL measurements.
Old 4th June 2019
  #19
Gear Maniac
 

Try running a patch cable from the output you are using back to the input, in place of the mic, and see if it is possible to get a clean measurement of that loopback. Input gain will need adjusting down to suit. That will quickly show if there is any monitoring path active, even Windows "Listen to this device" if using Windows drivers.
Old 4th June 2019
  #20
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Great idea John.

I set levels and did a measurement with a patch cable. The results I get are still absolutely crazy and are perfectly in line with the results I was getting earlier. Look at the attachments.
Attached Thumbnails
Crazy REW Results-spl.jpg   Crazy REW Results-distortion.png   Crazy REW Results-spectrogram.png  
Old 4th June 2019
  #21
Gear Maniac
 

Yikes! Can you attach the mdat for that measurement? It is worth going to the Windows audio settings Properties for the input and output and making sure that everything is turned off on the Enhancements tabs and that "Listen to this device" is not selected on the Listen tab for the input. Also check that the sample rate on the Advanced tabs matches the rate which is selected in REW (otherwise the OS will be resampling).
Old 4th June 2019
  #22
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I went to "Sounds" and right clicked on the playback speakers, went to the Advanced tab and made sure the sample rate matches.

The sample rate does say 32 bits 44.1k as the default format for running in shared mode, and that matches the REW and the Apollo settings, thought I don't know if that's the window you're talking about. I also went to the Windows Settings menu and checked all the sound settings again. There's nothing I can change. I clicked on the Advanced Sound Options at the bottom and there was nothing I could change there either. Some screenshots and mdat attached.

I really appreciate your help. I'm in the middle of a new acoustic construction project and I can't continue without measurements...
Attached Thumbnails
Crazy REW Results-sound-settings.jpg   Crazy REW Results-advanced-sound-settings.png  
Attached Files
File Type: mdat Loopback Measurement.mdat (2.69 MB, 6 views)
Old 4th June 2019
  #23
Gear Maniac
 

If you right click on the volume icon in the Windows taskbar and select Sounds from the popup you will get a dialog like this one. The Playback and Recording tabs have your device lists, and when you select a device you can click the Properties button to get a more detailed view of its settings including the tabs I mentioned.
Attached Thumbnails
Crazy REW Results-sounds.jpg   Crazy REW Results-playback.jpg  
Old 4th June 2019
  #24
Gear Maniac
 

As a PS, go into the REW soundcard preferences and select the input device, input, output device and output you are using, it is risky to rely on Windows default settings.
Old 4th June 2019
  #25
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Yes, I looked there already.
Attached Thumbnails
Crazy REW Results-general.png   Crazy REW Results-properties.png   Crazy REW Results-levels.png   Crazy REW Results-spatial-sound.png  
Old 4th June 2019
  #26
Gear Maniac
 

The input is the same I guess? There are two distinct peaks in the impulse response, something is interfering.
Attached Thumbnails
Crazy REW Results-ir.jpg  
Old 4th June 2019
  #27
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Okay, I just tried. No dice.

Quote:
Originally Posted by JohnPM View Post
As a PS, go into the REW soundcard preferences and select the input device, input, output device and output you are using, it is risky to rely on Windows default settings.
Old 4th June 2019
  #28
Gear Maniac
 

Might be worth selecting 16-bit 44.1k as the sample format for input and output in case there is some issue with the 32-bit format, though I can't think why there would be. Also worth checking the UA Console application in case something is enabled there which shouldn't be, a plug-in perhaps?
Old 4th June 2019
  #29
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No plug-ins anywhere. I can't change the bit depth in any application or in any settings panel, the only thing I can change is the sample rate.
Old 4th June 2019
  #30
Gear Maniac
 

I'm out of ideas then Chris. Your Jun 1 measurement was exactly how things are supposed to look, can't figure out what could have changed after that, sorry.
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