Much has been said about how Creative botched SB16's DSP compatibility with SBPro. From what I understand, "a hardware bug" ends up playing back stereo PCM samples in mono -- negating the main advantage of SB Pro support over plain SB.

I'm curious what is known about this hardware bug though. According to the SB hardware developer manual, the main difference between cards is the DSP firmware (and the mixer, to a lesser extent), and the primary difference between DSP v3.x and DSP v4.x is the latter dropped support for high-speed mode and now does 5000 Hz to 44100 Hz in normal mode (vs. mono 4k to 23k in normal, and mono 23k to 44.1k or stereo 11k to 22k in high-speed.)

Now, obviously, if DSP v4.x does not support high-speed mode at all, then SB Pro support would not work -- at all. At least not above 23kHz mono. So if it's just a flaw where samples are collapsed to mono, that can't be the case. Without knowing much about the hardware topology, it sounds like what's actually happening is that interleaved stereo samples are being sent to both DAC channels, or the software-configurable mixer stereo switch (removed on SB16's CT1745 vs. SBPro's CT1345) functionality isn't being replicated. The latter seems most likely to me, and the switch probably still exists within the DSP-to-mixer interface, but not user-accessible like before.

The other thing I wonder about is how useful the dual OPL2 feature is on the SB Pro 1.0. From the NerdlyPleasures blog, it doesn't seem like many games actually use this. There's far more support for the PAS, though. I know next to nothing about Media Vision's hardware before the PAS16. At least by the time they added OPL3 support, IIRC, it's accessible via the more traditional AdLib ports -- 0x388. I don't know about before that. I've been looking through the PAS code examples, but I haven't quite gotten a feel for how it works. Creative provided the SB audio libraries, but also documented the hardware interface pretty well. MV seems to give you a bunch of software interfaces and some code examples and send you on your way. 😉 So I haven't figured out how the different (OPL2, 2x OPL2, OPL3) variants are accessed.

Now, I've seen some game patches that will convert (e.g. Sierra titles) PAS support to work with SBPro 1 as well. I don't know how wide-spread these are, nor to what degree the OPL3 stereo interface differs from 2x OPL2 (I don't think it's possible to patch in OPL3 emulation of 2x OPL2, for e.g., but I could be wrong.) So I'm interested in more subjective opinions. Is it worth tracking down patches to add SBPro 1 support to all the games that support PAS? I really only know of one title where this is for sure possible: PQ3. That's good, it's one of my childhood favorites. But... from the intro sequence demo that someone posted, it was hardly mind-blowing. (Yay, the sirens pan from one side to the other.)

Enough jibber jabber. Vogons, DISCUSS! 🤣