/Library/Extensions/ all kext extensions malfunctioning

It's the one on the same page you provided a link for above (your third post counting from the top). Expand Drivers for Mac OS X and it's the first one.

Interesting. Even the download link carried over to this post. Just click that.

The .tar file within the installer .pkg expands out to 23 MB, but what actually comes out of the .zip file is this:

I've done most of the procedure up until sudo

Not sure what you mean. If you've run the installer, it pops up the admin user dialogue asking for your admin password. It needs that to run the sudo commands within the installer script.

as I have not enable sudo on my Mac

That's not something you "enable". sudo is always there as part of Unix.

If you've been clicking Cancel when is asks to enter your admin password, you're telling it not to proceed. In other words, the installer is then quitting without installing anything. Or, it is going through the rest of the script, but without an admin authorization, nothing is being installed with admin rights. That would certainly explain the OS messages that the kext drivers have not been properly installed.

Run the installer again and enter your admin password. If you are not the admin user on that Mac, you will have to get the person who is to enter the password.

Try reinstalling the software that added those extensions. Perhaps they have an updated version that will work.

I believe that error pops up do to invalid code signing of the kernel extension.

But even before I got the sudo command the system already kicked out the error:

The system extension “/Library/Extensions/FirefaceAudioDriver.kext” was installed improperly and cannot be used. Please try reinstalling it, or contact the product’s vendor for an update.

Yes, I mentioned it would likely do that. Unix is protecting itself. Which is exactly what it's supposed to do. As a secure OS, Unix makes it very difficult to install root level extensions without authorization, which is the entire point.

I've installed other apps that gave the same error and they gave no problem.

Given that additional information, I'd suspect something is wrong with the OS. You should make a backup, boot into Recovery mode (restart and hold the Command+R keys) and reinstall the OS.

I downloaded the driver and checked to see where and what it installs. The issue is that is doesn't really install anything. At least not according to unpkg and Suspicious Package. These are two utilities that determine what an installer package is going to put on the drive and where.

According to both apps, all it does is drop the file rme_fw_install.tar to the hidden folder tmp.

If you manually extract the Targa archive, these files are in it.

So if after running the installer, you're not finding FirefaceAudioDriver.kext in either Extensions folder location, that's why it's not working. The installer is not putting the items where it's supposed to. I haven't run the installer all the way through to see if that's what it really does.

Done.

Edit: Whoops! I made a boo-boo in the email instructions I sent. I wrote:

Then the script installs the current files from the download. First thing it does is check for the OS version. If it’s 10.5 through 10.8, it installs one set of the two identically named files. If it’s 10.9 (the “else”), it installs those two same named files from the folder 10_9. That itself may be a problem with the script since it doesn’t account for 10.10, 10.11 or 10.12. What I’m wondering is if it’s installing the wrong driver of the two.

Wrong. The installer directly checks for 10.5 through 10.8. If found, it installs the one set of files. The "else" doesn't check for any OS. Not having found 10.5 though 10.8 (all return false), it simply assumes 10.9 or later and installs those two same named files from the 10_9 folder.

Tested the installer. As you noted, the .kext file is installed to MacHD/Library/Extensions/FirefaceAudioDriver.kext . As it should be in El Capitan or Sierra.

I did this will SIP disabled and got no message about the kernel extension being improperly installed after the Mac restarted. Two apps were placed in the Applications folders, and the two .plist files were installed where you'd expect. That's all the further I can test though since I do not have this audio hardware.

Barney-15E is likely on the right track.

I believe that error pops up do to invalid code signing of the kernel extension.

I don't know how old your drivers are, but the IntelliType drivers for Microsoft's keyboards have similar issues since MS has not updated this software for the Mac since Lion. Because they have never been digitally signed, the new System Integrity Protection in El Capitan and Sierra will not allow it to work. The .kext file gets installed, but it won't load or run. Not to mention, such third party drivers are now supposed to installed to the /Library/Extensions/ folder, not the similarly named location in the System folder.

However, there is a way around this for many such outdated device drivers. It works with IntelliType and other unsigned software users have noted issues with on these forums.

1. Disable System Integrity Protection.

2. Reinstall your third party device drivers. With SIP enabled, they should be properly registered with the OS.

3. Re-enable SIP.