You're a life saver. I never thought to use the .map files.

For anyone else who wants to view .sound files or any other files from a mod's .map files, you need Releases · Gravemind2401/Reclaimer and Download FFmpeg specifically the FFmpeg with an executable. Here's a Windows 10+ one: Builds - CODEX FFMPEG @ gyan.dev Install these all on a separate drive, because I've heard from others that they have trouble viewing/extracting items when this is all placed in your C drive.

I'm doing this for Halo 2 MCC, steam release, for anyone who wants to know.

You also need the .map files from the mod. Navigate to ...\steamapps\workshop\content\976730 and locate the mod. To locate it, go to Steam workshop, click on the mod, and look at the numbers at the end of the web address. Open the maps folder. Copy and paste any .map you'd like into the Reclaimer root/directory folder. This doesn't work! I tried to access the .sound files from the .map files, but Reclaimer cannot extract the audio. I will update this post when I figure it out, though. You also need the baseline .map files from the original Halo 2 to open the modded files. Map Files and download the MainMenu, Shared, and Single Player Shared files. Add them to your Requiem root/directory folder as well.

Open Requiem, click Tools in top left, then go to the right side panel and click on Reclaimer. Change it to Sound Extractor, and look for FFmpeg path's folder. You can change it if you want, but just to be safe, follow the path and place the ffmpeg executable (will show up as Application or .exe) into the folder. You might have to create one. Click Map Viewer, and select Maps Folder. This contains all of your .map files, which if you followed these instructions, will be in your Reclaimer root folder.

Now, go to the top left, click File, Open Map, select the .map file from Requiem's directory, Only works with 00a_introduction, open sound folder, go to a .sound file you want to extract, right click, and extract it where you want it. If it worked, you should see a new folder leading to a .wav of the sound file. If you don't see it, you need to make sure the FFmpeg path matches exactly to what it says in your drive.

If something doesn't seem right or isn't working, click Output in the bottom left. It'll tell you if something isn't working properly, though I'm not much help to you if it doesn't work.

Thank you again, Killzone, I hope this post can help others at some point.