All current Turtle Beach soundcards are capable of recording and playing back 
audio simultaneously. There are some minor limitations, however. 

1) When playing back through the S/PDIF Digital Output, only pre-digitized
   sources such MP3, WMA or CD tracks will play through the S/PDIF Out. 
   Analog inputs (Mic, Line In, Aux) will not play through the S/PDIF Out. 

2) In the SRM and Montego DDL, the analog and digital inputs/outputs cannot 
   be used simultaneously. You must choose to hear either digital *or* analog
   inputs/outputs, not both at once. For example, if you set the soundcard 
   control panel Output Configuration to S/PDIF Out you will not be able to 
   hear audio through the analog (speaker) outputs. 

3) The S/PDIF Digital Input is meant for recording. You will not hear audio
   through the S/PDIF In until you've recorded the audio, saved it to your 
   hard disk, and then play it back. 

4) In Windows Vista, the "Stereo Mix" feature ("record what you hear") may not
   be available. In this case, only one analog input may be heard at a time. 
   No mixing of multiple inputs can be performed. At this time, the only 
   exception is the Riviera, which does have the Stereo Mix feature available.
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