Sound Card Calibration

[aceinc]

I want to use REW for Sub tuning. I have a Toshiba Tablet with a Realtek audio card built in. I downloaded the latest version (4.0) of REW. I ran the calibration, and the test afteward, and I get the attached graphs.

The raw test shows the freq response rolling off pretty high, and the compensated test still shows a curve that looks unusable for sub testing.

Am I doing something wrong, or do I have a soundcard?

[brucek]

The raw test shows the freq response rolling off pretty high, and the compensated test still shows a curve that looks unusable for sub testing.

The raw test with the loopback cable is the purple line and looks perfect.

You're right, the soundcard ain't great, but the soundcard calibration file (dotted line) compensates and gives a flat response ready for testing.

Many people use an external USB soundcard when they have a laptop for REW.

Once you take a measurement, be sure to post measurement graphs for subs using a vertical scale of 45dB to 105dB and a horizontal scale of 15Hz to 200hz.




brucek

[aceinc]

Sorry about that, I guess I was reading the graph wrong. I thought the dotted line was the compensated graph.

Paul

[koiman]

bruchek,
I am still trying to calibrate my Sound Blaster Live 24 I hooked up the line from my mike in to the speaker out and ran a sound card calibration and this is what I got any ideas.
Thanks,
Leon

[aceinc]

I'm sure brucek will have a definitive answer, but I believe the problem might be related to software that "enhances" the sound. Look in your system tray (bottom right) and see if there is any icons related to the sound card other than the volume control, if so turn it/them off, or exit it/them, and try again.

Paul

[Otto]

koiman wrote:

bruchek,
I am still trying to calibrate my Sound Blaster Live 24 I hooked up the line from my mike in to the speaker out and ran a sound card calibration and this is what I got any ideas.
Thanks,
Leon

Hi Leon,

You want to use "line in" rather than "mic in" on your soundcard.

[MakeFlat]

Leon, check that the CMSS light on the Sound Blaster is OFF. Also in the Creative Console named EAX, check that the sound effect option is unchecked (or not ticked).

[koiman]

Otto wrote:

Hi Leon,

You want to use "line in" rather than "mic in" on your soundcard.

otto,
When I use the line in I don't have enough power to attain a reading.

[koiman]

MakeFlat wrote:

Leon, check that the CMSS light on the Sound Blaster is OFF. Also in the Creative Console named EAX, check that the sound effect option is unchecked (or not ticked).

CMSS light is off.. EAX is set correctly.
Thanks,
Leon

[Otto]

koiman wrote:

otto,
When I use the line in I don't have enough power to attain a reading.

Hi there koiman,

Well, you generally want to use line in for the way we have things set up here. If you are using speaker out to line in, you should definitely be able to get a reading. Check your sound card settings via the speaker icon in the task tray. Are all levels up (both the speaker output as well as the line in knob)? Nothing muted (probably not, else I'd expect you to get nothing).

Similarly, in REW's "Settings", you can control the levels for the soundcard on the appropriately-named "Soundcard" tab. Make sure you have selected the correct inputs and outputs for the soundcard being used, and then ensure that the levels are at max (you can adjust them down later, if need be).

After all that, redo the soundcard cal and see what happens. You should definitely be able to get correct levels using speaker out and line in with a loopback cable.

What's the rest of your setup like? Specifically, during normal measurements, how will you feed the input of your soundcard? Radio Shack SPL meter? Other SPL meter? Mic and preamp? Mic only?

Thanks! Good luck!