5
Configuration 1
DirectSound and WDM Kernel
Streaming
Microsoft’s DirectSound and Windows Driver Model (WDM) are designed
to work hand in hand to take full advantage of audio card hardware and
provide kernel-mode software emulation of features not directly supported.
Kernel streaming allows audio data to be passed directly between driver
modules resulting in a robust, high performance integrated sound
processing system.
With its WDM driver, the Auricon can play MIDI files and audio CDs in
addition to Wave files. The kernel mixer allows multiple sounds from the
same or different applications to be played simultaneously, while the
kernel splitter automatically splits an input source to multiple applications.
Sampling rate conversion is automatically inserted if any of the playback or
recording streams differ from the card’s hardware sampling rate.
WaveRT on Windows 8, 7, Vista and Server 2012,
2008-R2 and 2008
The Auricon 4.4 uses the WaveRT driver model on Windows 8, 7, Vista and
corresponding server versions, giving the card’s PCI controller and digital
signal processor direct access to the audio engine’s buffers and position
registers. This allows audio transfers to proceed without any driver code
involvement, eliminating transitions to and from kernel mode and thus
improving efficiency and responsiveness. The card supports both pull mode
(the native mode for Windows 7 and 8) and push mode.
Topology
The Auricon 4.4 topology is shown in the diagrams at the end of this manual.
The playback topology consists of a master output level, mute control and
peak meter, and input monitor level and mute controls for each of the line
inputs. To these the kernel mixer adds virtual level and mute controls for
wave, synthesizer and CD outputs.
The record topology consists of a master input level, mute control and
peak meter, and level controls and mutes for the physical input and digital
loopback.
The digital loopback allows the output of the card to be digitally mixed
back into the input. This function is muted when Windows’ Digital Rights
Management detects that protected audio is being played, in accordance
with Microsoft’s specifications.
Note:
Under Windows 8, 7, Vista and
corresponding server versions, the loopback endpoint is disabled by default.
See the section on Windows 8, 7, Vista and Server 2012, 2008-R2 and 2008
above for instructions on how to enable it.
The range on the input and output master controls is -96dB to +6dB, while
the individual line controls range from -96dB to 0dB. Note that, for reasons
known only to Microsoft, on Windows 7 and Vista Service Pack 1 the 0dB
setting on the playback Master Volume control is 67, while on Windows 8 it
is 75.
To access the playback and record mixer controls on Windows XP, Server
2003 and earlier, double-click on the loudspeaker symbol at the bottom right
hand corner of the screen. On Windows Vista and later, right-click on the
loudspeaker symbol, select Playback Devices or Recording Devices, select the
desired endpoint, click on Properties, and then click on the Levels tab.
