User`s guide

20
User's Guide HDSP MADI © RME
12.3 Notes on WDM
The driver offers a WDM streaming device per stereo pair, like HDSP MADI (1+2). WDM
streaming is Microsoft's current driver and audio system. WDM streaming is hardly usable for
professional music purposes, as all data is processed by the Kernel Mixer, causing a latency of
at least 30 ms. Additionally, WDM can perform sample rate conversions unnoticed, cause off-
sets 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: <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 Sonar not only finds the stereo device
mentioned above, but also the 8-channel interleaved devices, and adds the channel number at
the end:
HDSP MADI (1+2) is the first stereo device
HDSP MADI (3+4) is the next stereo device
HDSP MADI (1+2) 3/4 are the channels 3/4 of the first 8-channel interleaved device.
We recommend to not use these interleaved devices. Also note that it is not possible to use one
stereo channel twice (the basic and the interleaved one), even with different applications.
Multi-Channel using WDM
The WDM Streaming device Loudspeaker (MADI Out 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: >Control Panel /Sound /Playback /Loudspeaker /Configure <
12.4 Multi-client Operation
RME audio interfaces support multi-client operation. Several programs can be used at the same
time. The formats ASIO and WDM can even be used on the same playback channels simulta-
neously. As WDM uses a real-time sample rate conversion (ASIO does not), all active ASIO
software has to use the same sample rate.
However, a better overview is maintained by using the channels exclusively. This is no limitation
at all, because TotalMix allows for any output routing, and therefore a playback of multiple soft-
ware on the same hardware outputs.
Inputs can be used from an unlimited number of WDM and ASIO software at the same time, as
the driver simply sends the data to all applications simultaneously.
RME's sophisticated tool DIGICheck is an exception to this rule. It operates like an ASIO host,
using a special technique to access playback channels directly. Therefore DIGICheck is able to
analyse and display playback data from any software, no matter which format it uses.