Can't calibrate my soundcard

[elee532]

Split from thread Cannot calibrate creative x-fi soundcard - brucek

brucek wrote:

Perfect.

But you don't have to ask, you can test it by now running a measurement test from 0-20000Hz of the loopback cable itself. If the soundcard cal file is good, then the frequency response of the cable should be flat.

For this test you leave the loopback cable on the right channel. Be sure there is no mic/meter cal and be sure you have saved the soundcard cal file. Then run a Measure.

After you get the flat response, you know you're ready to go, so remove the loopback and use that calibrated right channel for your mic and output to the receiver. The left channel is not used.

brucek

Hope you don't mind me jumping in your thread. I followed brucek's advice below to run a test measurement with the loopback cable connected.

I got different results with two different soundcard calibration files. However, as far as I can tell, I didn't make any changes between running the two soundcard calibrations. In both graphs below, the dotted line is the Soundcard Calibration and the red/green colored lines are the loopback measurement test. So, I guess two questions...

(1) Does either of these look like an accurate soundcard calibration? (I think #2 looks correct based on my reding of brucek's post below).

(2) Why might I gotten two different soundcard measurements like this?

Thanks!

[brucek]

Surprisingly enough, neither of them make a lot of sense.

You haven't really provided a large enough view to make an assessment of your soundcard calibration file. To do so, I need a full horizontal axis from 2-20000Hz.

Graph #1 shows about what you would expect from the standard soundcard cal file since it would normally be flat between the 15Hz to 200Hz shown. It would have to be quite an awful card that didn't offer this response.
But, when you measure a cable (which obviously has a perfectly flat response), it should return a flat line response when the soundcard cal file is there compensating for the soundcards inadequacies. In your case, the red line just doesn't register as anything I can identify. I can't imagine what you've done there.

Graph #2 shows a soundcard cal file that simply doesn't make sense. Soundcards don't start dropping off their response at 150Hz. I have no idea what you've done.

Start over and get a proper soundcard cal file. Show me the full axis response in a graph.
It's easy to do. Simply hook a cable on the right channel line-out to line-in and run the soundcard cal routine. Let's see the graph.

brucek

[elee532]

Does this make any more sense? I ran the soundcard calibration after hooking right channel line out to right channel line in. After saving the soundcard calibration, I ran a measurement again using the loopback between right in and right out. Thanks!

[elee532]

Ok. Here's another shot at it. This time, I changed my PC's speaker settings from 5.1 to stereo and changed the default format on both the speaker and line in from 24/192 DVD to 16/44.1 CD. Either of these last two make sense? Thanks!

[brucek]

Either of these last two make sense?

Yes, and I only had to look at the second last post to realize you must have a soundfield turned on. You absolutely have to be in stereo since REW produces a mono signal, it can't be decoded by any soundfields.

Yes, the last post shows the proper soundcard cal file.

Leave your soundcard in stereo. And also leave your receiver in stereo when you start sending it REW signals.

brucek

[elee532]

Thanks burcek! A little bit of a hassle changing from 5.1 to stereo everytime I want to take a reading. I don't suppose can offer any tips to make it easier? Two other key follow up questions...

(1) My PC is currently connected to my pre-pro via 7.1 analog inputs. Any reason this would cause a problem when doing readings with REW?

(2) The settings on my sound card offer options for default format ranging from 16/44.1 up to 24/192. Does this setting matter to REW?

Thanks!

[brucek]

hassle changing from 5.1 to stereo everytime I want to take a reading. I don't suppose can offer any tips to make it easier?

No tips. It has to be in stereo and you'll only use the right channel. The mic/meter hooks to the right line-in and the right line-out is the signal the connects to the receiver.

My PC is currently connected to my pre-pro via 7.1 analog inputs. Any reason this would cause a problem when doing readings with REW?

No problem other than only the mono signal coming from the right and left line-out will be used. You can manually move the cables to the other speaker channels you want to test.

The settings on my sound card offer options for default format ranging from 16/44.1 up to 24/192. Does this setting matter to REW?

Only use 44.1 or 48Hz sample rate.

brucek