User`s guide

User's Guide Fireface 800 © RME

8.3 Notes on WDM

The driver offers a WDM streaming device per stereo pair, like Fireface ADAT 1 (1+2). WDM

streaming is Microsoft's current driver and audio system, directly embedded into the operating

system. WDM streaming is hardly usable for professional music purposes, as all data is proc-

essed by the so called Kernel Mixer, causing a latency of at least 30 ms. Additionally, WDM can

perform sample rate conversions unnoticed, cause offsets between record and playback data,

block channels unintentionally and much more.

Several programs do not offer any direct device selection. Instead they use the playback device

selected in Windows under

XP: <Control Panel/ Sounds and Multimedia/ Audio>

Vista/7/8: <Control Panel/ Sound/ Playback>

The program Sonar from Cakewalk is unique in many ways. Sonar uses the so called WDM

Kernel Streaming, bypassing the WDM mixer, thus achieves a similar performance to ASIO.

Because of the driver's multichannel streaming ability (option Interleaved, see chapter 12.4),

Sonar not only finds the stereo device mentioned above, but also the 8-channel interleaved

devices, and adds the channel number at the end:

RayDAT ADAT (1+2) is the first stereo device

RayDAT ADAT (3+4) is the next stereo device

RayDAT ADAT (1+2) 3/4 are the channels 3/4 of the first 8-channel interleaved device.

It is not recommended to use these special interleaved devices. Also it is not possible to use

one stereo channel twice (the basic and the interleaved device).

Multi-Channel using WDM

The WDM Streaming device Loudspeaker (Analog 1+2) of the RME driver can operate as usual

stereo device, or as up to 8-channel device.

An 8-channel playback using the Windows Media Player requires the speaker setup 7.1 Sur-

round. Configure as follows:

XP: >Control Panel /Sounds and Multimedia /Audio /Volume /Speaker Settings /Advanced <

Vista/7/8: >Control Panel /Sound /Playback /Loudspeaker /Configure <