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.

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