User`s guide

12
User's Guide Fireface 400 © RME
Enable MMCSS for ASIO activates support with higher priority for the ASIO driver. Note: At this
time, activating this option seems to be useful only with the latest Cubase/Nuendo at higher
load. With other software this option can decrease performance. The change becomes active
after an ASIO reset. Therefore it is easy to quickly check which setting works better..
Settings of the main page
Buffer Size
The setting Buffer Size determines the latency between incoming and outgoing ASIO and WDM
data, as well as affecting system stability (see chapter 9). While ASIO can use any offered
buffer size, WDM is limited to 256 (XP) or 512 samples (Win 7/8). The driver handles this auto-
matically, higher settings are only applied to ASIO while WDM will stay at 256/512 internally.
Bandwidth
Allows to reduce the amount of bandwidth used on the FireWire bus. See chapter 7.6.
All channels (default) activates all 18 input and output channels
Analog + SP. + ADAT 1-4 activates all 8 analog channels plus SPDIF plus 4 ADAT channels
Analog + SPDIF activates all 8 analog channels plus SPDIF
Analog 1-8 activates only the first eight analog channels
The string Errors does not refer to buffer errors, but FireWire transmission errors. The display
will be reset on any start of a playback/record. More information can be found in chapter 30.3.
Output Format
Word
The word clock output signal usually equals the current sample rate. Selecting Single Speed
causes the output signal to always stay within the range of 32 kHz to 48 kHz. So at 96 kHz and
192 kHz sample rate, the output word clock is 48 kHz.
Optical
The optical TOSLINK output can operate as ADAT or SPDIF output.
SPDIF
The SPDIF output can have the Channel Status Consumer or Professional. For further details
please refer to chapter 23.2.
Options
SPDIF Input
Defines the input for the SPDIF signal. 'Coaxial' relates to the RCA socket, 'Optical' to the opti-
cal TOSLINK input.
TMS
TMS activates the transmission of Channel Status data and Track Marker information from the
SPDIF input signal.
WDM Devices
Defines the number of WDM devices. A reduction accelerates the change of the sample rate,
reduces the time of continued CPU load, brings quicker behavior on plugging and unplugging
the unit, and reduces the boot time of Windows with connected interface. The best setting is 0,
means no WDM devices at all. Only ASIO and MIDI are active then. A typical setting is 1 device
(WDM for Media Player etc.), still causing a much quicker change than a full WDM channel
count.