User’s Guide HDSP System RPM
© RME
13
The channel assignment using PowerDVD is:
1 (first chosen playback channel) - Left
2 - Right
3 - Center
4 - LFE (Low Frequency Effects)
5 - SR (Surround Right)
6 - SL (Surround Left)
Note 1: Setting the card to be used as system playback device is against common sense, as
professional cards are not specialized to play back system sounds, and shouldn't be disturbed
by system events. To prevent this, be sure to re-assign this setting after usage, or to disable
any system sounds (tab Sounds, scheme 'No audio').
Note 2: PowerDVD 5 no longer supports a starting channel other than channel 1.
Note 3: In WinDVD 5, a channel-seperated 5.1 playback using the HDSP requires a change in
the registry. Start regedit, go to
HKEY_CURRENT_USER / Software / InterVideo / DVD5 /
AUDIOCHAN
, and set its value to
4
(hexadecimal). Additionally select 'Waveout' as Audio
Renderer in the Audio configuration dialog.
Warning: Changes to the registry are done at
your own risk. Danger of complete data loss!
8.5 Low Latency under MME (Buffer Size Adjustment)
Using Windows 95 or 98 the MME buffer size was nothing to worry about. Latencies below 46
ms were not possible. Meanwhile both computers and operating system have become much
more powerful, and since Windows ME/2000/XP latencies far lower can be used. SAWStudio
and Sonar allowed to use such low settings from the start. Sequoia was updated in version
5.91, WaveLab in version 3.04.
In the HDSP's Settings dialog the MME buffersize (in fact the DMA buffer size) is set with the
same buttons as the ASIO buffer size. Our test computers allow to use settings down to 64
samples without clicks. Please note that this setting only defines the buffer size of the
hardware. The true and effective latency is configured within the MME application!
Attention: the DMA buffers must not be larger than the application's buffers. This case can
happen unnoticed when using ASIO and MME at the same time (multi-client) and setting
ASIO to 186 ms, while the buffers in the MME application are still set for a lower latency.
Playback will be stuttering and audio will be distorted.
Example: when you set the RPM to 512 you can't use 128 in any program. But setting DMA to
128 allows to use 128 and all higher values within the software.
Please also note that this is a 'you're welcome to try' feature. We can't guarantee that you will
be able to use 3 or 6 ms with MME. Simply check out by yourself which lowest setting your
system and software allows. Some motherboards with insufficient PCI bandwidth (especially
older VIA based ones) suffer from crackling at settings below 512. Be sure to set the buffer size
to 512 or higher in such a case (or trash the motherboard…).
