Using ALSA to Control Linux Audio - page 2
ALSA User Toolsalsamixer has three screens per sound card: Capture, Playback, and All. Use the Tab key to navigate through these. On the Capture screen you'll find options for different capture sources, depending on what your sound card support. Take a look at the Input Source in Figure 3. This has two options: Front Mic and Line, and you use the up and down arrow keys to choose.
The other sliders operate the same way as for playback, and you may have to try a bit of trial and error to learn which slider, or combination of sliders, controls which microphone port.
Press F2 to see all the system information on your sound cards. If you have more than one sound card press F6 to display a sound card chooser.
As you can see, using ALSA is pretty easy. In our next installment we'll learn how to configure the default playback device, and how to test speakers.
Carla Schroder is the author of the Linux Cookbook and the Linux Networking Cookbook (O'Reilly Media), the upcoming "Book of Audacity" (NoStarch Press), a lifelong book lover, and the managing editor of LinuxPlanet and Linux Today.