Soundcard spoiled ?

[buzztiger]

I tried calibrating my internal soundcard according to the help file. However i ended up with the following graph. I have muted all the sound except for the wave and playcontrol before measuring the loopback. Does this mean my soundcard is screwed up ?

[Otto]

Hey there, buzz, and welcome to the Shack!

Just to be sure -- are you using a stereo cable in the loopback path, and using "line-out" and "line-in" for input and output, respectively (don't use "mic-in" and "headphone"). Don't worry, we'll get you up and running. I don't think your soundcard is dead.

[buzztiger]

I just figured that my soundcard driver got messed up. After reinstalling the driver i could get a souncard calibration file. Then i plucked in my mic which is the MCACC mic provided with pioneer into the souncard mic in. It picks up sound but the levels are too low. Is there any way i could bring up the levels ? I have used this mic with truerta and it works. Any suggestons on wat i should do ?

[Otto]

Hi buzz.

Usually, we use a mic that provides a line-level output signal. Many of us use a RS or Galaxy SPL meter, and many of us use "real" micropohones fed to a preamp and then to the soundcard. Either of those methods results in a line-level signal.

If your mic is not providing a line-level signal, and you are going into the soundcard on the "line-in" port (as I suggested in my previous post), then you'll get really low readings. You should be able to increase the level of the reading by using that mic with the "mic-in" port. However, this may cause a couple problems.

First, you may have trouble with the calibration when using the line-out and mic-in ports. The mic-in path is looking for a much lower signal that what the line-out will generate. You may be able to get a better result by decreasing the output of the soundcard, but it's not the normal way of doing things.

Second, if you use that mic, I presume that you don't know its frequency response. This is a very important part of the measurement, and you will be pretty much guaranteed to have a skewed result if you don't use some type of calibration file with that mic. If that mic was supplied with another program or device that's used for measuring frequency response, I'd think that that program or device knows the frequency response of the mic and accounts for it as part of its measurement process.

If you don't already have an SPL meter, you should get one. Not only can you use it as the mic for these tests, you'll also need it for level calibration. It's a very useful device. I have the Galaxy CM-140 (I think it's the 140, maybe the 130...), and they have been very consistent from one to another (that means that the calibratoin file we use is applicable and accurate for all of these meters). If you can't find the Galaxy, try to get a Radio Shack meter; they are widely available (I see you are in Singapore).

Good luck!