Audio capture problem for a beginner

[jbaugh]

I have a Mac Pro that has a bad contact on the audio input port on the back. The mini audio input plugs fit loosely and I can't get dependable connection. Therefore, I have been investigating the use of a USB device to input audio. I purchased a Behringer U-Control UCA202 device which connects to a USB port. It has RCA plugs for input and output. For audio output it works very well. But I cannot figure out how to capture audio with this device. The audio input source I'm trying to input is the output from a wireless mic receiver. When I view the input signal on a sound application on my Mac I can see that there is a very low amplitude input signal. If I shout very loudly into the microphone the amplitude of the signal increases significantly. But I cannot capture any audio using the UCA202 to input the signal.

I am able to record audio through the built-in mini audio port on the back of the computer. But as I've said, there is a poor connection at this port and it is not dependable.

I'm really new at this stuff. But I don't know where to go next. It seems the problem has to do with a low input audio signal strength. Do I need an amplifier between my source and the U-Control?
Thanks.
John

[Soopafresh]

I wonder if your levels in either your sound settings or the application itself is too low. Does the USB device act as a line level device or a mic level device? The difference is huge as far as the amount of signal coming into the computer.

Also, I had a USB microphone which needed updated drivers because the default signal levels were too low. You've checked the website for new drivers?

[jbaugh]

Soopafresh,
Thanks for your response. I too think that the problem seems to relate to an inadequate signal strength coming into the computer.
It is interesting that the output through the USB device works great. It's just the input that is a problem. There is virtually no documentation with the USB device, so I don't really know the answer as to whether it is acting as a line level or mic level device. Perhaps this is the problem. It may be expecting line level input and it can't deal with the lower amplitude mic input?

The application I am using is Quick Time Broadcaster. The input signal is set to maximum in this software. In my "Sound" system preferences the USB shows up under both the "input" and "output" tabs. The output is configurable only as to right/left balance.
Under the "input" section of sound preferences is the following:
"Settings for the selected device: The selected device has no input controls."

There are multiple drivers available on the manufacturer's website for the Windows platform, but none for Mac OSX. When I have some free time to experiment I will see if I can get this device to work on my Windows machine. If I can figure out how to do it, I might also try running the input signal through some amplification before sending it to the computer to see if that works

The documentation specifically states that no drivers are needed for the device to function.

I'll keep pluggin' away and I'll report back if I ever get this figured out.
Thanks.
John