Perhaps you know it, but if not, here's the site that should contain all necessary information:
http://support.turtlebeach.com/site/kb_ftp/570.asp
Despite the fact that the Monte Carlo 928 has a Crystal CS4231 on it, it is said that the card is "OPTI 928" based.
If you have not allready done it, look up the various faqs, where I found this information concerning SB:
"Be sure that the Monte Carlo is in SB mode. You can verify this by typing <drive letter> :\mcmode /S. (Be sure to include the space between the "e" in "mode" and the "/" .
EXAMPLE from the prompt: C:\MCMODE /S
Doing this command will specify that the Monte Carlo is operating in Sound Blaster mode which was specified in the installation program (DOS portion only).
The possible settings are as follows:
I/OAddress: 220, 240
Interrupt (or IRQ) 7, 5, 11
DMA 1, 0, 3"
Many cards that provide Sound Blaster and Windows Sound System compability are only able to work in one of the two modes at the same time.
I have a Turtle Beach Tropez Classic that can not play Soundblaster sounds as long as it is in WSS mode. You have to change this using the dos setup utility.