CMI8738/PCI C3DX Series 

Chip Function List

Model MODEM SPDIF/ZVport channel


О О 6
CMI8738/PCI-6CH-MX x О 6
CMI8738/PCI-6CH-LX x x 6
CMI8738/PCI О О 4
CMI8738/PCI-SX x x 4

HRTF-based 3D positional audio(C3DX™) for 4 / 6 CH output.

Professional digital interface, supporting 24-bit SPDIF IN/OUT  (44.1K and 48K)

Built-in 32ohm earphone buffer,  ZV port, and PCtel® HSP56   Modem™ interface.

32-bit PCI bus master.

Comprehensive driver support: Microsoft® DirectSound™3D,  EAX™, Linux™, BeOS™, etc.

Microphone echo and Karaoke ascending/descending key   effects.

Single chip design, digital power +3.3V, analog power +5V,  128 pins QFP.

C3DX™ is the registered trademark of C-Media.


PCI-Base HRTF 3D Extension Positional Audio Chip
With high speed PCI V2.1 bus controller and legacy audio SBPro® DSPemulator,CMI8738 is designed for PC add-in cards and all-in-one motherboards. No external CODEC is needed in CMI8738: CMI-8738 supports the legacy audio – SBPRO™, FM emulator/DLS wavetable music synthesis, and HRTF 3D positional audio functions.  Drivers support EAX®, Karaoke Key, Echo……functions.  Above all CMI8738 supports PCtel® HSP56 (1789) interface.  




Physical Chip

Being compatible with A3D™ and DirectSound™ 3D, CMI8738 meets PC99® requirements, and supports professional digital audio interface such as 24-bit SPDIF IN (0.5V ~ 5V)and OUT(44.1K and 48K format).

 CMI8738 uses HRTF 3D extension technology to enhance traditional HRTF 3D positional audio by substituting two-speaker system by four or six - speaker one (it supports additional 2 ch 16-bit DAC to provide rear side audio and another 2 ch for subwoofer/Center).  It greatly improves HRTF 3D positional audio quality and successfully removes the sweet spot limitations: users can enjoy genuine 3D audio gaming effects, and don't have to worry about the environmental confinement any more.  

Add-In Card Type