The X3 may be used for listening to other audio sources, such as the output of
your TV, the output of your PC sound card, an MP3 player, home theater system,
etc. For example, the illustration below shows how to connect the X3 to the
output of a home theater system. In this case, the transmitter audio input 
would be connected to the stereo line output on the home theater receiver. 

In some systems, this would be the recording line output, typically used for 
a cassette recorder, while on other systems it would be a pre-amplifier line 
output. Refer to the instructions included with your unit for details.

The volume control on the X3 transmitter should be set to maximum and the
volume control on the headphone should be adjusted to a comfortable level. 
If the sound is distorted because the audio source output is too loud, then
the volume control on the transmitter should be reduced to a lower level that
better accommodates the source volume.

  
_____________________________________________________________________________