Do you have a CD audio cable attached?

No, with all the pulling the card in and out for testing, I didn't bother.

Here's some more pics of the setup

sry 1 more

OK. So I've tried some stuff and learned some things.

As I mentioned before the crackling somehow goes away when I go into the DIAGNOSE utility and get to midi on page 2. Since I am unable to exit the utility in this state (I must complete the diagnostic or the sound card will crash and spew noise), on a hunch I thought that whatever that program did between page 1 and 2, it must be changing something on the card that makes the crackle disappear. However I didn't know how to use this information so I tried fiddling with my BIOS.

I tried all sorts of stuff on the BIOS from wait states to delayed transactions to PnP vs legacy settings on the IRQs and nothing had any sort of effect at all.

Then I had an idea to go into descent's setup because it lets you test the card in the setup program. I switched the music back to OPL2 mode and it sounded like shitting on a pile of puke (this is yet another problem that I haven't figured out yet) but then I went to OPL3 mode... same thing. THEN I went back to general midi and the problem was gone. No crackling. I rebooted the machine to see if I could turn the problem on and off and sure enough, cycling the chip from GM to OPL2 to OPL3 to GM again clears up the crackling somehow.

So at this point I'm like ok let's undo all the BIOS changes but after I did that, my little Descent trick didn't work anymore so I started rolling back the changes 1 at a time and determined that the 8 bit I/O recovery time had to be maxed out at 7 or else the fix wouldn't work.

So... bearing in mind that I'm just being scientific and don't know as much as most here about how computers work, it "seems" like the ISA bus is too fast for the OPL chip pathway responsible for midi sound. Now since I've got a dreamblaster, GM mode works probably because all of the work is being offloaded to that daughterboard, but it's got this crackling, which may be coming from the SB16, until you reset/toggle the modes a couple of times. When you don't go through the dreamblaster, the SB16 just can't handle whatever the problem is, whether it's speed or whatever, and it produces horrible loud garbage that persists after you exit whatever program you were in and requires a reset to fix.

This really sucks because on the 1 hand I want to slow down the ISA bus for the sake of the sound card but on the other hand I have a SCSI controller working just fine at that speed and my video card is weak and needs the FSB boost for the games I'm throwing at it. The cpu overclock is also jumpers so that's always a pain to switch back and forth.

I'm just wondering if anybody has had this problem on an overclocked rig who didn't have sound problems or if there's a recommendation on how I can fix the issue in software. It's not the end of the world I guess if I can't get midi natively from the card but the problem is some games seem to require the older SB16 music whether I have the dreamblaster or not and those games are horribly garbled and basically unplayable with sound. Should I just buy another SB16 and hope that manufacturing differences between cards will make the next 1 stronger if I'm lucky?

EDIT:

The P54CQS chip seems to use a 60MHz FSB (I'm guessing 30MHz doubled???) If the ISA is 1/4 the speed it would have to be 1/4 of 30, not 60 and that is less than 8 MHz so at 133MHz the FSB would be 66 and half of that is 33 and 1/4 of that is 8.3, which I thought was perfectly normal for ISA to run at so how in the heck is this too fast?