User`s guide

User's Guide Fireface 800 © RME
19
7.5 Bandwidth
This option allows to reduce the amount of bandwidth used on the FireWire bus. A typical ex-
ample is the use of the Fireface with a laptop. Only in rare cases both ADAT ports are needed,
in many cases even both stay unused. The option Analog+SPDIF will reduce the amount of
constantly (!) transferred data from around 5 MByte (10 in both directions) to only 2 MByte (4 in
both directions). The FireWire connection will be more stable, reliable and robust, leaving addi-
tional bandwidth for other devices. At the same time the CPU and system load is reduced, as
less channels have to be processed and to be transferred. More details are found in chapter
30.4.
Available Settings
All channels (default) activates all 28 input and output channels
Analog + SPDIF + ADAT1 disables channels 21–28 (ADAT2)
Analog + SPDIF activates all 10 analog channels plus SPDIF
Analog 1-8 activates only the first eight analog channels
8. Operation and Usage
8.1 Playback
In the audio application being used, Fireface must be selected as output device. This can often
be found in the Options, Preferences or Settings menus under Playback Device, Audio Devices,
Audio etc.
We recommend switching all system sounds off (via >Control Panel /Sound<). Also Fireface
should not be the Preferred Device for playback, as this could cause loss of synchronization
and unwanted noises. If you feel you cannot do without system sounds, you should consider
using the on-board sound device or buying a cheap Blaster clone and select this as Preferred
Device in >Control Panel /Multimedia /Audio< or >Control Panel /Sound /Playback<.
The screenshot shows a
typical configuration
dialog of a (stereo) wave
editor. Audio data is sent
to an analog or digital
(ADAT / SPDIF) port,
depending on which has
been selected as
playback device.
Increasing the number
and/or size of audio
buffers may prevent the
audio signal from break-
ing up, but also in-
creases latency i.e.
output is delayed. For
synchronized playback
of audio and MIDI (or
similar), be sure to
activate the checkbox ‘Get position from audio driver’.
Note on Windows Vista/7/8
:
Since Vista the audio application can no longer control the sample rate under WDM. Therefore
the driver of the Fireface 800 includes a workaround: the sample rate can be set globally for all
WDM devices within the Settings dialog, see chapter 7.1.