Firstly, is your SB16 a PCI one? (I've never used them, but I think they come in PCI or ISA flavours). If it's PCI, then try sndconfig. If it's ISA, you might want to look into ISAPNP stuff (but try sndconfig first anyway).
Secondly, what monitor are you using, and what 'driver' did you select? I found that sometimes the general monitor 'drivers' work a little better than the specific drivers. But only sometimes.