While for the most part the only audio-related settings you interact with on your Mac are the volume controls, there might be times when you need to look up or configure more specific details.
There are three basic areas in OS X where you can look up audio information and configure it: The system preferences, the system information utility, and the Audio MIDI Setup utility.
Sound system preferences

The Sound system preferences show available devices, but offer limited configuration and information about them (click image for larger view).
While you can see the available audio input and output devices in your Sound system preferences, the only options you have here are to set volume and stereo balance settings. However, this will give you a quick overview of the devices you can use.
Related to this is the Volume menu extra, where you can by default change the system volume in the menu bar, but if you hold the Option key when clicking this you will see the available input and output devices and be able to select them for use.
System Information

Selecting audio devices in System Information will show more details than the system preferences (click for larger view).
The System Information tool can be accessed in your Applications > Utilities folder, or by choosing About This Mac from the Apple menu, and then clicking More Info followed by pressing Command-N at the info window that pops up. In this program, you will see a number of hardware, software, and networking categories in the sidebar. Locate the Audio category in the “Hardware” section, and select it.
In this section, you will see the same devices listed as were shown in the Sound system preferences; however, you will see more information such as the number of supported channels, the component manufacturer, and the currently configured sampling rate for the device.
Audio MIDI setup
The final area is Apple’s Audio MIDI Setup utility (also in the Applications > Utilities folder). In this tool, you can set properties for all available audio input and output devices, and in doing so see more of their capabilities. Simply select a device in the program’s sidebar, and you will see all the configuration options for it, including a menu for sampling rates and another for the number of channels and the bit depth used.
In addition to the audio format settings, you can use Audio MIDI Setup to configure which audio channels play to which speakers. Just click the “Configure Speakers” button, and you can use the drop-down menus under each speaker to assign an audio channel to it.