In detail—special properties of the drivers.
DirectSound & WDM
It goes without saying that the drivers of the PHASE system also support Microsoft's
DirectSound or DirectSound 3D interface. What's more, the software complies strictly with
Microsoft's WDM specification. For example, the drivers are able to play back audio data
streams from multiple applications in parallel (multi-client, a “luxury” that faithful TerraTec
customers have enjoyed since 1997).
Unlike MME drivers, WDM (Windows Driver Model) drivers are based on 32-bit architec-
ture. 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 file called up first. All further data streams—those
called up during the run time of the first file—are interpolated as required and their pitch is
not affected.
Note:
Unlike PCI cards, the PHASE 24 FW 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.
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 simultane-
ously 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 officially 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.
PHASE 24 FW (English)
25
