How to install MetaAudio on Half-Life (25th Anniversary update) - Restore EAX/A3D Audio (2025)

How to install MetaAudio on Half-Life (post-25th anniversary update) - UPDATED 2025

The content on this Pastebin may be changed in future, the W.I.P version of the plugins now works with 25th anniversary. See the GitHub issues here: https://github.com/LAGonauta/MetaAudio/issues/57

WARNING: You cannot play any servers with VAC Enabled if you launch the game with MetaHook/MetaHookSv.

NEW METHOD (RECOMMENDED):
Step 1. Download MetaHookSv (latest version): https://github.com/hzqst/MetaHookSv/releases (get MetaHookSv-windows-x86.zip)

Step 2. Extract everything on MetaHookSv to a folder (such as Half-Life folder)

Step 3. Run "MetahookInstaller.exe", select game (Half-Life), then install. A shortcut to launch Metahook should be created.

Step 4. Go to Edit plugin list and enable "MetaAudio.dll", click save.

Launch Half-Life with Metahook using the shortcut that the installer create. You can also alternatively launch MetaHook.exe with "-insecure -game valve" command line. Replace "-game valve" with "-game (mod_name)" if you want to play HL1 mods while having MetaAudio enabled.

You can also select custom game in MetaHook installer to install MetaHook on other GoldSrc mods aswell. If MetaAudio fails to work with your mod, copy "metahook" from "valve" (you need MetaHook installed for Half-Life first), and paste it into your mod folder (example: CLAnniversary for Crack-Life Anniversary, gearbox for HL: Opposing Force, etc...).

OLD METHOD (FOR OLDER VERSION):

Step 1. Download MetaHookSv (latest version) and libsndfile: https://github.com/hzqst/MetaHookSv/releases
https://github.com/libsndfile/libsndfile/releases

Step 2. Download the work-in-progress version at https://github.com/LAGonauta/MetaAudio/actions (Actions tab)
Select the most recent one on Actions tab > Under Artifacts > Click on MetaAudio, and it will be downloaded automatically.

Step 3. Extract everything on MetaHookSv to a folder, go to "MetaHookSv-windows-x86\Build\valve" folder,
DELETE the "resource" folder, this will avoid breaking the Video Options, hiding the new "Enable texture filtering".
then run "install-to-HalfLife.bat"
Wait and then, close the Notepad window that opens up the plugins.lst file (used to add dll plugins). There should be a shortcut to launch MetaHook ("MetaHook for HalfLife") near the extracted folder.

If you forgot to remove that folder, don't worry, you can just verify the game files.

Step 4. Open MetaAudio.zip, then go to "Release" folder > drop MetaAudio.dll to "...\Steam\steamapps\common\Half-Life\valve\metahook\plugins" folder (if its doesnt exist, create one)

Step 5. Go to "...\common\Half-Life\valve\metahook\configs" and open plugins.lst, replace everything or keep everything, and type metaaudio.dll (or copy paste) on the top, save.

Step 6. Edit the shortcut ("MetaHook for HalfLife") by right click > Properties > Put +al_doppler 0.3 after the end of the Target. It should look like this: "...\Steam\steamapps\common\Half-Life\metahook.exe -insecure -game valve +al_doppler 0.3"

Launch the game on the "MetaHook for HalfLife" shortcut and it should work.

This will also fix the low quality audio on the restored Valve intro.

### KNOWN ISSUES
- This may not work on Goldberg Emu, only legit copy of the game (including free to keep during Nov 17 to Nov 20). Launch the executable on the shortcut instead.
- Valve may update the game at any time, which could break MetaHookSv. Wait for them to be updated and download the latest version and install it again.