RME Fireface UCX II 40-Channel USB-B Audio/MIDI Interface - Manual (Page 34)

34 User's Guide Fireface UCX II © RME
15. Mac OS X FAQ
15.1 MIDI doesn't work
In some cases the applications do not show the MIDI port. The reason for this is usually visible
within the
Audio MIDI Setup . It displays no RME MIDI device, or the device is greyed out and
therefore inactive. Mostly, removing the greyed out device and searching for MIDI devices again
will solve the problem.
The Fireface
’ MIDI is class compliant. Therefore it comes without a driver. OS X recognizes it as
MIDI device and will be using it with the driver included in the operating system.
15.2 Repairing Disk Permissions
Repairing permission can solve problems with the installation process - plus many others. To do
this, launch
Disk Utility located in Utilities . Select your system drive in the drive/volume list to
the left. The First Aid tab to the right now allows you to check and repair disk permissions.
15.3 Supported Sample Rates
RME's Mac OS X driver supports all sampling frequencies provided by the hardware. This in-
cludes
32 kHz and 64 kHz , and even 128 kHz, 176.4 kHz and 192 kHz .
But not any software will support all the hardware's sample rates. The hardware's capabilities
can easily be verified in the
Audio MIDI Setup . Select Audio devices under Properties of: and
choose the Fireface. A click on Format will list the supported sample frequencies.
15.4 Channel Count under Core Audio
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 output operates in S/MUX4 mode, so the number of
available channels is limited to 2.
It is not possible to change the number of Core Audio channels without a reboot of the comput-
er. Therefore whenever the Fireface changes into Double Speed (88.2/96 kHz) or Quad Speed
mode (176.4/192 kHz) all channels stay present, but become partly inactive.
Single Speed Double Speed Quad Speed
Fireface Analog 1 to 8 Fireface Analog 1 to 8 Fireface Analog 1 to 8
Fireface SPDIF Fireface SPDIF Fireface SPDIF
Fireface AES Fireface AES Fireface AES
Fireface ADAT 1 to 8 Fireface ADAT 1 to 4 Fireface ADAT 1 to 2