So here is a little story with a happy (for now) ending...
An year or so ago I finished my newest PC and the Sound Blaster Z was a part of it. The one in my signature.
All of this was put to work by everybody's "favorite" OS Windows 10. Aaaand the issues started...
Brand new platform (back then) there were BIOS issues, Driver issues, compatibility issues and of course the SBZ Dolby Digital Live issue... Somehow back then I was able to fix the issue and I had no issues with is until about 3 weeks ago when I got the 1903 Windows 10 update and also I updated my BIOS to the latest one. I tried everything... Clean reinstall of Windows, going back to the BIOS I had before, tried all available drivers and registry patches, HPET Enable/disable, I even contacted Creative's technical support, but all I was able to get from them for more than 10 days was several different versions of that same registry patch (just different values in the keys). At least they acknowledged that there is such an issue with some specific hardware configurations.
Two days ago while reading other posts and articles for that same issue, I clicked on a link that sent me to Microsoft's web site (Microsoft Update Catalog or something like it) there I saw all the Creative Sound Blaster drivers that were ever released on Windows Update. What caught my eye were the driver versions: for SBZ the ones they have are version 6.0.102.xx and 6.0.103.xx while the a lot newer drivers for the Sound BlasterX AE5 (the fancy one with the RGB) the latest version is 18.104.22.168.... Then a thought pop'd in my head... what if I can use those newer (supposedly made for Windows 10) drivers on the SBZ? It appears that both the SBZ series and the newer SBX AE5 are using the SoundCore3D Audio processing unit (or at least very similar versions of it).
At first I tried directly installing the driver on top of what I already had but Windows stated that there is no compatible driver in the folder and sent be packing...
After mentioning some mothers... I opened the INF from the SBX AE5 driver and the INF from the SBZ driver and oh miracle! Those had almost identical structure sans the hardware IDs and some additional things pertaining to what hardware is supported by the driver. Confidant in my skills (or lack of such) I copied all the relevant lines from the SBZ INF with the hardware IDs describing the Sound Blaster Audio Controller and the Sound Blaster Z Audio Device to the SBX AE5 INF and tried installing it again... That of course didn't work as after modifying the INF file, the Digital Certificate was now broken and Windows sent me packing again but this time I was prepared!
I quickly rebooted to Advanced Startup Options and used F7 (or only 7) for Disable Driver Digital Certificate Enforcement (or whatever it was exactly).
This time the driver installed for both devices and asked me to reboot.
After reboot (and no BSOD which I expected to be fair) I still had sound! I went in device manager to check if the "new driver" is really installed and it was. Then I checked Sound Blaster's control panel and all the setting were back to their default ones (just like after you just installed the driver) I enabled DDL (5.1 was already selected by default) and oh sweet music for my ears everything was working!
It has been 3 days since then and I watched a lot of movies, Youtube and what not and there have been ZERO audio issues with DDL (no, distortions, no channel swapping, no audio cutouts).
Now for the part you've all been waiting for... DISCLAIMER
YOU ARE FOLLOWING THE STEPS BELOW AT YOUR OWN RISK!! I'M NOT RESPONSIBLE FOR ANY DAMAGE THAT YOU MAY CAUSE TO YOUR WINDOWS OS BY IMPROPER INSTALLATION OF THE DRIVER!!!
I HAVE TESTED THIS MOD ONLY ON MY SYSTEM AND IT WORKS FOR ME. THERE IS NO 100% GUARANTEE THAT IT WILL WORK FOR YOU!
The attached driver will only work properly on Windows 10 64bit (I did not bother with the 32bit part of the INF)
1. Download and install the newest available driver for the Sound Blaster Z (this is needed for all the software things like the Sound Blaster Control Panel, DDL, Speaker Setup and so on.) At this point you will have sound and you may even get up to 30 minutes of proper DDL before it begins to act-up... (If you already have the driver installed you can skip this step) Newest driver I have found is this one: LINK
2. Download and unpack the attached archive. Inside is the moded AE5 driver and the last registry patch that I was sent by Creative. Apply the registry patch.(not sure if it is needed but since I have already applied it before doing all this, it may be a part of the solution. Anyway it will not hurt anything to apply it)
3. Go to Settings>Recovery>Advanced Startup and click on "Restart now". Then click Troubleshoot>Advanced options>Startup Settings and click on Restart.
The system will reboot and will present you several options. Press F7 (or just 7) on the keyboard. This will disable the Digital Signature Enforcement and will allow the installation of the modded driver.
4. After the system loads, go to Device Manager and right-click on the "Sound Blaster Audio Controller". Select "Update Driver" then select "Browse my Computer..." On the next screen choose "Let me pick from a list....", then on the next screen click on "Have Disk" and find the folder you extracted the driver in. If you did it right you will be greeted with a single "Sound Blaster Audio Controller" option. Next and so on until the driver is installed. It will ask to reboot but not yet.
5.Still in Device Manager, right-click first on the "Sound Blaster Z" device and repeat the procedure from step 4. Now you can restart.
6. After reboot have completed, go to the Sound Blaster Control Panel (it should be in your taskbar) and check if 5.1 is selected and then enable DDL from the "Cinematic" tab.
7. Enjoy and report back if it worked for you.