How-to: Resolving ISA sound and OPL2/3 issues \ VOGONS

How-to: Resolving ISA sound and OPL2/3 issues

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First post, by PhaytalError

Posted on 2012-06-29, 14:23

PhaytalError Offline

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I am a big SB16 fan, why? I dunno, I guess I like all it's little quirks, and the "noise" aka hiss, is not noticable on the PC speakers I own [perhaps they filter out noise].

However, lately i've been stumbling over something, and thats OPL3 corruption, it's been plaguing me for days, and only happens in random games and apps and i've been wondering what is it?

Well messing around in the BIOS I remembered a "trick" I did back in 1997 [my motherboard is an ASUS P3B-F v1.04, I had this same model back in 1997], the trick to correcting OPL3 corruption is to enable the "Passive Release" and "Delayed Transaction" options if available in your BIOS, and to increase [the lower the faster, however increasing the number is important to fix ALL OPL3 corruption] the 8-bit I/O Recovery to it's highest number which is 8 BUSCLK, you can set [or leave] 16-bit I/O Recovery to 1 BUSCLK.

So what's going on? Why is this needed? The answer is simple your ISA and PCI devices are in a rut! PCI clock frequencies are much higher (33 MHz) compared to ISA frequencies (16 MHz), and it has to be forced to wait longer (more clock cycles) for the ISA device(s) to "catch up".

Don't even think about using anything below 8 BUSCLK's because it doesn't resolve all issues, for instance using 7 BUSCLK, X-Wing begins corrupting when the Tie Fighters destroy the rebel ship during the opening cinematic.

In other words, 8 BUSCLK is the magic number for ISA sound cards. 😀

I [and you] can now enjoy apps such as AdTracker 2, and games such as X-Wing and more without any hiccups or sound issues. 😁

DOS Gaming System: MS-DOS, AMD K6-III+ 400/ATZ@600Mhz, ASUS P5A v1.04 Motherboard, 32 MB RAM, 17" CRT monitor, Diamond Stealth 64 3000 4mb PCI, SB16 [CT1770], Roland MT-32 & Roland SC-55, 40GB Hard Drive, 3.5" Floppy Drive.

Reply 1 of 7, by keropi

Posted on 2012-06-29, 15:35

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interesting... from what cpu and upwards those opl problems appear?

🎵 🎧 ⏳ ⚡ PCMIDI MPU , OrpheusII , Action Rewind , Megacard and 🎶GoldLib soundcard website

Reply 2 of 7, by PhaytalError

Posted on 2012-06-29, 15:56

PhaytalError Offline

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keropi wrote:
interesting... from what cpu and upwards those opl problems appear?

I'm not too sure, but it's a timing issue with the ISA bus when a PCI bus is present, more so than the CPU being the culprit. I just did some extensive testing on my rig, and it cleared up all the issues I had been having.

Also, from a quick search on the internet it seems that MDGx confirmed it as being a ISA/PCI timing issue as well. I really need to bookmark his site, it's chock full of DOS and Win3.x/Win9x tricks and tips! 😳

Reply 3 of 7, by keropi

Posted on 2012-06-29, 16:11

keropi Offline

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I see... thanks for the info PhaytalError , it might come handy in my pentium1/5x86 builds!

🎵 🎧 ⏳ ⚡ PCMIDI MPU , OrpheusII , Action Rewind , Megacard and 🎶GoldLib soundcard website

Reply 4 of 7, by keropi

Posted on 2012-06-29, 16:11

keropi Offline

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I see... thanks for the info PhaytalError , it might come handy in my pentium1/5x86 builds!

🎵 🎧 ⏳ ⚡ PCMIDI MPU , OrpheusII , Action Rewind , Megacard and 🎶GoldLib soundcard website

Reply 5 of 7, by PhaytalError

Posted on 2012-06-29, 16:56

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keropi wrote:
I see... thanks for the info PhaytalError , it might come handy in my pentium1/5x86 builds!

You're quite welcome. Have fun with those builds! 😁

Reply 6 of 7, by Ace

Posted on 2012-06-30, 02:30

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PhaytalError wrote:
X-Wing begins corrupting when the Tie Fighters destroy the rebel ship during the opening cinematic.

You're talking about the floppy disk edition here, right? That game is NOTORIOUS for major audio glitches on faster computers. It depends on the sound card, but generally, those with true OPL3 are most prone to these audio glitches. If you use a computer with a Pentium MMX or similar CPU, some notes will come out wrong, but the sound is still generally okay, but on anything faster (Pentium II and up), the FM Synthesis is just a mess of jumbled garbage. LucasArts' SoundBlaster drivers are so badly made, not only do you get audio glitches on faster computers, but with some setups, the SoundBlaster sound options all cause the game to have no sound whatsoever. The fix for this was posted by Dvwjr on this very forum: Star Wars X-Wing (floppy version) Sound Blaster driver fix

Download XWing_SBpro_fix.zip, rename SBPRO_W.IMS to ADLIB_W.IMS, problem solved, but your sound card MUST be on address range 220. I tried messing with all those settings (though I think many of my motherboards are missing those options; I know they have options to set the I/O recovery times, but as for the rest, I don't know), and at least for X-Wing, this works better than those methods (I got jumbled garbage regardless of what I altered in the BIOS), but as it's a game-specific thing, it's not exactly the ideal way to fix major audio glitches like these.

Creator of The Many Sounds of:, a collection of various DOS games played using different sound cards.

Reply 7 of 7, by PhaytalError

Posted on 2012-06-30, 02:48

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Thanks for the info, Ace.

Although 8 BUSCLK setting worked for me on my system, i'll be sure to try out that fix. 😀

It's odd how game developers, especially Lucasarts, never considered the future of PC's and had oddball timings in their code.

What's even worse are those "486 code tricks" in some game code that pretty much kamikaze when they run on anything faster than a 486. 😖

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