Note: the initial post in this thread has now been updated with a new version of the guide which uses a slightly different approach. I'm archiving the original version here, in case someone still wants to use that.
So why would anyone want to do this? Because it allows you to use soundfonts for General MIDI in DOS games. I know this is already possible with WDM drivers but those drivers limit DOS emulation to SBPro (instead of SB16) and they sometimes cause issues with Windows games that use EAX. This method allows you to run VxD drivers and still use soundfonts for DOS games. Note that this only works when DOS games are running from within Windows 98. If you choose "Restart in MS-DOS mode" then the soundfonts won't work and the card will use those crappy .ECW sets instead. To my knowledge, there is no way to use .SF2 based soundfonts in pure DOS with a Sound Blaster Live.
Anyway, you don't need to modify the drivers in any way for this to work. All you need is some way to unpack a single CAB file, and 7-Zip does that nicely. This guide assumes that you have a clean install of Windows 98SE and a Sound Blaster Live card. It will probably fail if you already have other versions of Creative's drivers installed, but it works 100% on a clean install.
EDIT - I have personally tested this method with a Sound Blaster Live 5.1 (model SB0100). Later on, different people have tested it with some other SBLive models as well, and all information about that has been summarized in this post
1.Hardware and software requirements:
Before proceeding to the next section of this guide, make sure that the following hardware and software requirements are met. If they are not, the driver installation may fail.
1.1 Upon booting up your system, enter the BIOS and disable all COM and LPT ports in order to free up additional resources. If your motherboard has an integrated sound card, network card or any other integrated device that you are not using, disable it in the BIOS as well. Lastly, if you are not using USB, disable that too
1.2 During the driver installation process, the SBLive should be the only sound card in your system. Using a second sound card may cause the driver installation to fail
1.3 This guide has only been tested on Windows 98SE. A clean install of Windows 98SE must be performed before attempting the driver installation procedure. Do not use any unofficial "service packs". Only install the drivers for your motherboard and graphics card until you complete all the steps in this guide
1.4 The SBLive requires one free IRQs for the card itself. The value assigned to this IRQ varies from system to system, but it should not be the same as the IRQ assigned to the SB16 emulation device. Additionally, the SB16 emulation device requires three I/O ports, one IRQ and two DMA channels. The default values are: I/O ports 220, 330 and 388, IRQ 5, DMA 1 and DMA 5. If any of those resources are not free, the driver installation may fail. To determine if your system has enough free resources, under Windows 98SE click Start > Programs > Accessories > System Tools > System Information > Hardware Resources and check the IRQ, DMA and I/O sections
2.1 Download and install 7-Zip version 9.20 for 32-bit Windows (it works fine on Win98)
2.2 Download the Audigy2 ZS driver CD ISO
2.3 Use 7-Zip to extract the contents of the "Audigy_2_ZS_Install_CD.7z" to C:\AU1
2.4 After that, right click on "C:\AU1\Audigy 2 ZS Install CD.iso" > 7-Zip > Extract Here to unpack the contents of the ISO image (it may report some errors with CHM files but that's ok)
2.5 Download the Audigy DOS support package
2.6 Extract the contents of audigy2-dospack.rar to C:\AU2 (note: it appears that this archive was created with a newer version of WinRAR, you may need to unpack it on your modern computer)
3. Windows Driver Installation
3.1 Right click on My Computer > Properties > Device Manager > Sound, video and game controllers. If there is an "Ad Lib Compatible (OPL2)" device present there, right click on it > Remove > Ok
3.2 Run C:\AU1\CTShared\LaunchApp\SysInfo\Setup.exe which will install the Creative System Information utility and update the InstallShield Engine (important later)
3.3 Run C:\AU1\DirectX\dxsetup.exe which will install DirectX 9.0a and restart your computer (if you already have a newer version installed, skip this step)
3.4 Go to C:\AU1\Audio\Drivers\VxD > right click on VxD.cab > 7-Zip > Extract Files > C:\AU1\Audio\Drivers\ (this should populate the existing VxD folder with the files from the CAB)
3.5 Run C:\AU1\Audio\Drivers\CTZAPXX.exe and select "Driver Installation" and "VXD Drivers" then click Ok
3.6 Driver installation will take several minutes, don't interrupt the process until you are prompted to Restart then click Ok
3.7 After the restart, wait until the installer finishes, then go to Start > Settings > Control Panel > Multimedia > Audio > Playback > Advanced Properties > Performance > Sample Rate Conversion Quality > move the slider to "Best"
3.8 Run C:\AU1\Audio\SFBMgr\Setup.exe and install the Sound Font Bank Manager (if you get an InstallShield Engine error here, repeat step 3.2)
Congrats on installing the Audigy VxD driver on a SBLive, now we'll tackle DOS compatibility.
4. DOS Driver Installation
4.1 Run C:\AU2\AUDIGY DOS DRIVER\Setup.exe and restart when prompted
4.2 Wait until the Creative SB16 Emulation drivers are fully installed (this may take a few minutes)
4.3 During the boot process you might see a "Config file incomplete" error. Restart your computer one more time and it should disappear
If the installation was successful, you should now have the following under Device Manager:
Congrats on being able to use soundfonts in DOS games while running VxD drivers. Currently, the SBLive is using Creative's default 2 MB soundfont. If you want something that sounds much better, see below.
5. SC-55 Sound Font Installation (optional)
5.1 Download Patch93's SC-55 soundfont and extract the archive contents to C:\AU3
5.2 Download SF Pack and extract the archive contents to C:\AU3
5.3 Run C:\AU3\SFPACK.EXE > Ok > File > Add Files > Files of type: SFPack Files > C:\AU3\SC-55.sfpack > Open
5.4 After that, click File > Go/Stop. Wait for about 30 seconds. Now, if everything worked ok, you should have a SC-55.sf2 file in C:\AU3 (file size should be 45.1 MB)
5.5 Start > Programs > Creative > SoundFont Bank Manager
5.6 Click on "Midi Devices" and use the slider to set SoundFont Cache to slightly more than 50 MB then click Ok
5.7 Click on "Bank" then click on the default soundfont (2GMGSMT) to select it, then click Replace, point to C:\AU3\Sc-55.sf2 wait a few seconds until it loads then click Ok
5.8 Run your favorite DOS game (like Duke3D for example) and in setup choose General MIDI for music
Listen to the MP3s attached to the first post in this thread to check how Duke3D sounds on a SBLive using this soundfont. For comparison, here's Duke3D on a real SC-55.
6. Getting MT-32 compatibility in pure DOS (optional)
6.1 Start > Shutdown > Restart in MS-DOS mode
6.3 Make sure that the MT-32 option is checked, then click Save and press ESC to exit
6.4 Run your favorite DOS game that supports MT-32 (like Monkey Island for example)
Note that MT-32 emulation doesn't sound too great on this card, but I'm including it for completeness sake. That said, these drivers also allow your SBLive to emulate FM Synthesis, should you want that. Of course, this sounds different from a genuine OPL3 chip, but I'd still consider it tolerable. Sample MP3s are attached to the first post of this thread.