CME UF400e, User Manual, Page: 21 / 32

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luxury” that faithful TerraTec customers have enjoyed since 1997).
Unlike MME drivers, WDM (Windows Driver Model) drivers are based on 32-bit
architecture. It is also the basis for advanced interfaces such as “ASIO” or “Direct-X”.
WDM sample rate (SR) interpolation
The multi-client capability of the WDM architecture also permits the simultaneous
playback of multiple audio data streams with differing sample rates. The sample
frequency used for all streams is based on the fi le called up fi rst. All further data
streams—those called up during the run time of the fi rst fi le—are interpolated as
required and their pitch is not affected.
An SR conversion/interpolation does always result in a certain loss of
quality, however.
You should therefore ensure that you do not use several programs
simultaneously with differing sample rates for applications in which the highest
possible audio quality is vital. For example, it’s best to only have the playback
software running when transferring a piece of music at 44.1 kHz to a DAT recorder.
WDM kernel streaming
WDM kernel streaming also represents a new technology for Microsoft. Like
established models such as Steinberg’s ASIO interface, kernel streaming is designed
to provide extremely fast access to audio hardware, bypassing the mixer for direct
hardware access. Thus the name “kernel streaming”—the kernel of the Microsoft
Windows operating system permits the audio data to stream directly through. This
extension of the WDM format was designed after a proposal by Cakewalk and is
now offi cially recognized by Microsoft. The deployed software (such as audio/MIDI
sequencers or software synthesizers) must support the WDM function directly,
however. One of these programs, for example, is the “Sonar” recording software
produced by the Cakewalk company.
The Mac OS X drivers
In OS X (currently OS 10.3.4), the UF400e system is supported completely by Apple
CoreAudio and CoreMIDI. Device-specifi c drivers are not required. The UF400e can
be selected as the default recording and playback device in “Control Panel ->Sound”
UF400e Firewire Audio Expansion Board User’s Manual
Note:
Unlike PCI Boards, the UF400e system cannot
automatically synchronize the required sample rate. Select the
sample rate manually using the dropdown menu in the Control
Panel to avoid a SRC. The sample rate set in the control panel will
always be applied.