RME HDSPe MADI FX [21/87] Notes on wdm

User's Guide HDSPe MADI FX © RME

12.3 Notes on WDM

The driver offers a WDM streaming device per stereo pair, like AES (1+2), and 8-channel de-

vices for MADI, like MADI (1-8). 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 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 HDSPe MADI FX uses 8-channel interleaved devices for all three MADI I/Os. When re-

cording with WDM or WDM KS based programs the input choice might be limited to stereo or

left/right, so channels 3 to 8 of each block are not available. This problem does usually not exist

on the playback side, and never under ASIO.

Multi-Channel using WDM

The WDM Streaming device Loudspeaker (MADI 1-8) 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 <

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.