C-Media CMI8738

From the ALSA wiki

Contents 1 Initial Setup 2 Controls 3 Troubleshooting Hints 3.1 No Sound from Analog Speakers

Initial Setup

Before plugging speakers into the card, check the Master volume control is at a reasonable level, but not at maximum (you might damage your speakers, or worse, your ears).

Also check the following controls are unmuted (and set to reasonable levels):

• PCM
• Synth
• CD

Controls

The following is a partial list (it ignores Capture controls):

• Master
• 3D Control - Switch
• PCM
• Synth
• Line
• Line-In Mode
  • Rear Output
  • Line-In
• CD
• Mic
• Mic Boost
• Phone
• IEC958 5V
• IEC958 Copyright
• IEC958 In Monitor
• IEC958 In Phase Inverse
• IEC958 In Select
• IEC958 In Valid
• IEC958 Loop
• IEC958 Mix Analog
• IEC958 Output
  • on - for digital output
  • off - for analog output
• PC Speaker
• Aux
• Exchange DAC
  • on
  • off
• Four Channel Mode

The Master control on this card is purely a volume control (it has no 'mute' switch).

Troubleshooting Hints

No Sound from Analog Speakers

If you hear no sound when using this card with analog speakers/earphones, try switching off the following:

• IEC958 Output
• Exchange DAC

These can be switched off using alsamixer, amixer or other available mixers. (Tested using Debian 4.0r6, alsamixer v1.0.13 and headphones connected to the SPK jack socket.)