RME Audio Hammerfall HDSP AES-32, User Manual

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User's Guide HDSP AES-32
© RME
12.3 Notes on WDM
The driver offers a WDM streaming device per stereo pair, like
AES (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 processed 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 : < 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:
AES (1+2) is the first stereo device
AES (3+4) is the next stereo device
AES (1+2) 3/4 are the channels 3/4 of the first 8-channel interleaved device.
We recommend to not use these special interleaved devices. Also note that it is not possible to
use one stereo channel twice (the basic and the interleaved device), even with different applica-
tions.
Information on multichannel WDM is found in chapter 12.4.
12.4 Multi-client Operation
RME audio interfaces support multi-client operation. This means several programs can be used
at the same time. Also all formats (ASIO, WDM, GSIF) can be used simultaneously. The use of
multi-client operation requires to follow two simple rules:
•
Multi-client operation requires identical sample rates!
I.e. it is not possible to use one software with 44.1 kHz and the other with 48 kHz.
•
Different software can not use the same channels at the same time.
If for example Cubase uses channels 1/2, this playback pair can't be used in Gigastudio (GSIF)
nor under WDM (WaveLab etc.) anymore. This is no limitation at all, because TotalMix allows
any output routing, and with this a playback of multiple software on the same hardware outputs.
Note that the inputs can be used at the same time, as the driver sends the data to all applica-
tions simultaneously.