User Manual
User's Guide Fireface UC © RME
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14. Using more than one Fireface
The current driver supports up to three Fireface UC. All units have to be in sync, i.e. have to
receive valid sync information (either via word clock or by using AutoSync and feeding synchro-
nized signals).
• If one of the Firefaces is set to clock mode Master, all others have to be set to clock mode
Slave, and have to be synced from the master, for example by feeding word clock. The
clock modes of all units have to be set up correctly in the Fireface Settings dialog.
• If all units are fed with a synchronous clock, i.e. all units show Sync in their Settings dialog,
all channels can be used at once. This is especially easy to handle under ASIO, as the
ASIO driver presents all units as one.
The driver takes care of the numbering of all Firefaces, so that it doesn't change. The unit with
the lowest serial number is always 'Fireface (1)'. Please note:
• If the Fireface (1) is switched off, Fireface (2) logically turns to the first and only Fireface. If
Fireface (1) is switched on later, the numbering changes and the unit becomes Fireface (2)
immediately.
• The driver has no control on the numbering of the WDM devices. Therefore it might happen
that the WDM devices (2) are mapped to unit (1), especially when switching on more Fire-
faces during a Windows session. A reboot with all Firefaces already operational should
solve this problem.
Note
: TotalMix is part of the hardware of each Fireface. Up to three mixers are available, but
these are separated and can't interchange data. Therefore a global mixer for all units is not
possible.
When using more than one Fireface UC the USB bus might get overloaded. To prevent this
connect all units to different USB busses. This should be possible without further hardware as
many popular USB 2.0 interfaces come as twins, which can be checked in the Device Manager
as follows:
• Connect the Fireface UC to a USB port
• Start the Device Manager, View set to ‘Devices by Connection’
• Expand ACPI x86-based PC, Microsoft ACPI compatible System, PCI bus
Here you usually find two entries of a USB2 Enhanced Host Controller. All USB devices are
connected via a Root Hub, the Fireface UC will show up here too. By a simple reconnection to
other ports this view lets you check to which one of the two controllers the Fireface is connected
to. And with two units, if they use the same controller or not.
This information can also be used to makes sure that an external USB hard drive will not inter-
fere with the Fireface UC, by ensuring its connection to a different bus (controller).
Especially with laptops it can be seen that all internal devices and all sockets are connected to
the same controller, and that the second controller is not used at all. Then all units operate on
the same bus and fight against each other for bandwidth..