Specifications

171
Set WDM Channel Maps
WDM applications are often mainly
inclined to think in terms of sound cards,
and have trouble interfacing to a true
multi-channel system such as the
H8000FW.
As a result the H8000FW offers some
options to produce “Channel Maps”,
which disguise the H8000FW as the sort
of configuration that the WDM
application may be expecting.
Here we have an example of the
H8000FW masquerading as a set of
Surround Sound speakers.
Select input or output as appropriate, and
then click and drag from the WDM Channels list at the left to the Device channels table to connect the
H8000FW channels to the WDM outputs or inputs. Selecting Reset connects all channels.
Global Settings - DPC Page
A Deferred Procedure Call (DPC) is a Windows driver mechanism that can consume a lot of CPU time at
critical periods, which can reduce the performance and reliability of audio applications and drivers. (See
http://en.wikipedia.org/wiki/Deferred_Procedure_Call for technical information). WDM systems are
particularly sensitive to such problems.
Problems caused may include drop-outs, or in serious cases, Locking and Unlocking of the system. This will
often be accompanied by relay clicks from the H8000FW.
To analyze these problems, this page includes a
DPC Latency checker which can help analyze
the delays introduced by DPCs.
If you temporarily enable this and let it run for long enough for any problems to have occurred (a few
minutes), then move the cursor over the Recommended Operation Mode field, you will be given a
description of the computer’s performance.
If there are problems, you will be recommended to change the Operation Mode. Be aware that the safer
(higher numbered) modes will add latency, so you should try and find the source of any problems first.
You should also check that your system has the latest Network drivers. In particular, the use of Microsoft
Outlook with an Exchange server (but not POP3 or IMAP) has been reported to cause significant latency
increase. It is desirable to keep all network activities to a minimum when doing critical sessions.