User Manual
28
User's Guide Fireface UC © RME
13.2 Channel Count under ASIO
At a sample rate of 88.2 or 96 kHz, the ADAT optical input and outputs operate in S/MUX mode,
so the number of available channels per port is reduced from 8 to 4.
At a sample rate of 176.4 and 192 kHz, the ADAT optical input and outputs operate in S/MUX4
mode, so the number of available channels per port is limited to 2.
Please note that when changing the sample rate range between Single, Double and Quad
Speed the number of channels presented from the ASIO driver will change too. This may re-
quire a reset of the I/O list in the audio software.
Single Speed Double Speed Quad Speed
Fireface UC Analog 1 to 8 Fireface UC Analog 1 to 8 Fireface UC Analog 1 to 8
Fireface UC SPDIF L / R Fireface UC SPDIF L / R Fireface UC SPDIF L / R
Fireface UC AS 1 to 2 Fireface UC AS 1 to 2 Fireface UC AS 1 to 2
Fireface UC ADAT 3 to 4 Fireface UC ADAT 3 to 4 Fireface UC ADAT 3 to 4
Fireface UC ADAT 5 to 6 Fireface UC ADAT 5 to 6 Fireface UC ADAT 5 to 6
Fireface UC ADAT 7 to 8 Fireface UC ADAT 7 to 8 Fireface UC ADAT 7 to 8
13.3 Known Problems
If a computer does not provide sufficient CPU-power and/or sufficient USB-bus transfer rates,
then drop outs, crackling and noise will appear. Such effects can be avoided by using a higher
buffer setting/latency in the Settings dialog of the Fireface UC. Furthermore PlugIns should be
deactivated temporarily to make sure they do not cause these problems.
More information can be found in chapter 35.3.
Another common source of trouble is incorrect synchronization. ASIO does not support asyn-
chronous operation, which means that the input and output signals not only have to use the
same sample frequency, but also have to be in sync. All devices connected to the Fireface UC
must be properly configured for Full Duplex operation. As long as SyncCheck (in the Settings
dialog) only displays Lock instead of Sync, the devices have not been set up properly!
The same applies when using more than one Fireface UC. They all have to be in sync. Else a
periodically repeated noise will be heard.