User Manual
User's Guide Fireface UCX © RME
79
Recording a Software's playback 
In real world application, recording a software's output with another software will show the fol-
lowing problem: The record software tries to open the same playback channel as the playback 
software (already active), or the playback one has already opened the input channel which 
should be used by the record software. 
This problem can easily be solved. First make sure that all rules for proper multi-client operation 
are met (not using the same record/playback channels in both programs). Then route the play-
back signal via TotalMix to a hardware output in the range of the record software, and activate 
Loopback for recording. 
Mixing several input signals into one record channel 
In some cases it is useful to record several sources into only one track. For example when us-
ing two microphones recording instruments and loudspeakers, TotalMix' Loopback mode saves 
an external mixing desk. Simply route/mix the input signals to the same output (third row), then 
redefine this output into a record channel via Loopback. This way any number of input channels 
from different sources can be recorded into one single track. 
29.6 MS Processing 
The mid/side principle is a special positioning technique for 
microphones, which results in a mid signal on one channel and a 
side signal on the other channel. This information can be trans-
formed back into a stereo signal quite easily. The process sends 
the monaural mid channel to left and right, the side channel too, 
but phase inverted (180°) to the right channel. For a better 
understanding: the mid channel represents the function L+R, 
while the side channel represents L-R. 
During record the monitoring needs to be done in 'conventional' stereo. Therefore TotalMix also 
offers the functionality of a M/S-decoder. Activation is done in the Settings panel of the Hard-
ware Input and Software Playback channels via the MS Proc button. 
The M/S-Processing automatically operates as M/S encoder or decoder, depending on the 
source signal format. When processing a usual stereo signal, all monaural information will be 
shifted into the left channel, all stereo information into the right channel. Thus the stereo signal 
is M/S encoded. This yields some interesting insights into the mono/stereo contents of modern 
music productions. Additionally some very interesting methods of manipulating the stereo base 
and generating stereo effects come up, as it is then very easy to process the side channel with 
Low Cut, Expander, Compressor or Delay. 
The most basic application is the manipulation of the stereo width: a change of the level of the 
side channel allows to manipulate the stereo width from mono to stereo up to extended. 










