If you have sound problems playing through Media Center, please read the Getting Started topic on this wiki. It will help you set up audio on your machine.
Each audio output type has different settings. In Tools/Options/Audio, they can be set in the second section.
Some devices have problems switching sample rates. Some don't play high sample rates well. You can use MC's Output Settings in DSP Studio to force everything to a rate that works.
Some devices need special packaging. See the DAC Settings topic.
Some devices work more reliably with smaller or larger buffers.
MC has several volume options. Click on the speaker icon next to the volume slider to try them.
If you use ASIO, make sure you have the latest driver from the manufacturer of the device.
USB 3.0 drivers may also need to be updated.
The thread called Weird and Wonderful has a list of problems caused by other software or hardware.