User`s guide

User's Guide Fireface UC © RME
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17. Mac OS X FAQ
17.1 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 – MIDI Window. 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 UC 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.
17.2 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.
17.3 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 for the analog and
SPDIF I/Os.
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 – Audio Window. Select the Fireface UC. A
click on Format will list the supported sample frequencies.
17.4 Channel Count under Core Audio
The Fireface’s ADAT optical interface offers sample rates of up to 192 kHz using a standard
ADAT recorder. For this to work single-channel data is spread to two or four ADAT channels
using the Sample Multiplexing technique. This reduces the number of available ADAT channels
from 8 to 4 or 2.
It is not possible to change the number of Core Audio devices without a reboot of the computer.
Therefore whenever the Fireface UC changes into Double Speed (88.2/96 kHz) or Quad Speed
mode (176.4/192 kHz) all devices stay present, but become partly inactive.
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 ADAT 1 to 2 Fireface UC ADAT 1 to 2 Fireface UC ADAT 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