Not all S2000 games support enhanced sounds. IGT got lazy towards the end and made up games with no enhanced sound support. The prevailing theory is that the SB chip did not have enough space to accommodate the larger paytables, Casino support api's, and the sound routines on the 512KB space, so they did away with the sound parts. I don't know if this is true or not, but it seems like most 3 reel single payline machines support enhanced sounds while the 5 reel 9 or 15 payline games do not have sound on them, other than a few.