# ADS External Sound Card



## Mike P. (Apr 6, 2007)

This is the measurement from the sound card calibration. This is my first attempt at REW and I have no idea how to interpret this. Any comments welcome.


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## Wayne A. Pflughaupt (Apr 13, 2006)

Hi Mike,

That doesn't appear to be a valid sound card calibration. After calibration, REW will generate a response graph that resembles this. Note that the graph is a tight scale of only +/- 3 dB, and it's full range, not just the bass frequencies. Typically a sound card will start falling out at the bottom end, as you see here. Yours looks pretty whacked - it rises at the bottom end? That would be pretty strange. Do you have a link for the sound card? Can't say I've ever heard of an ADS.










Regards,
Wayne


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## Mike P. (Apr 6, 2007)

it's the ADS LL5-RDX-150, specs are here:

http://www.adstech.com/products/RDX-150/specifications/RDX-150_spec1.asp?pid=RDX-150

It has separate L + R RCA audio in and out jacks. I did the loop back with only the Right input and output jacks.

http://www.adstech.com/products/RDX-150/specifications/images/RDX-150_REARp.jpg


I'm not sure why your graph has a wider frequency range then mine, this is what REW gives me. I'm using Windows XP and a RS digital SPL meter with the proper calibration file installed.


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## JohnM (Apr 11, 2006)

You need to remove the cal file and uncheck the "C weighted SPL meter" box in tyhe mic/meter settings when doing the loopback check, otherwise you just see the cal file inverted because the cal is being applied to a piece of wire, which doesn't need it. You can set the frequency axis to logarithmic by clicking the freq axis button near the top right side, and you can change the range shown by clicking the zoom +/- buttons at the right hand end of the frequency axis or by using the button at the top right to set the graph limits. There's more info on those buttons in the graph panel help http://www.hometheatershack.com/roomeq/wizardhelp/help_en-GB/html/graphpanel.html#top


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## Mike P. (Apr 6, 2007)

Cal file removed and "C weighted SPL meter" box unchecked. Is this good?


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## glaufman (Nov 25, 2007)

Not really sure... If that's a measurement sweep after calibration to check for a flat line, it would look like the cal file isn't being applied.
It may help if I clarify the steps:
Remove cal file. Uncheck C-weighted box.
Connect Loopback cable. Run the soundcard calibration. Make sure the file saves and is listed in the filename box.
then run a real measurment sweep, which should appear flat. In the plot window, check the box for soundcard cal so it shows the trace it's using for the cal.


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## JohnM (Apr 11, 2006)

I should have been a bit clearer, sorry. It's just the mic/meter cal file that needs to be removed, the soundcard cal file should stay loaded.


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## Mike P. (Apr 6, 2007)

Ran the sound card calibration, then ran a run a real measurement sweep. This is the result.


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## laser188139 (Sep 19, 2009)

It's funny. The curve in the thumbnail in the left margin looks normal, but your primary graph does not. It appears you took a measure of the sub alone, but your graph limits were set to full range. Try changing your graph limits to the normal ones for a sub, 20Hz-200Hz. Also, you want the x-axis to be log scale, not linear scale. That's the Freq Axis button next to the Graph Limits button in the upper right corner.

Bill


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## JohnM (Apr 11, 2006)

To save an image of the graph click the floppy disk icon in the bottom right corner of the graph.


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## Mike P. (Apr 6, 2007)

Thanks for the help. I'm off to work for a week and will try again when I get back.


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