Mod Version:
ds: 3.4.9.12
Forge Version:
2676

Link to crash log (if applicable):
https://pastebin.com/q43nTzV4
Description:
game crsahes on startup, something related to the sound system or registry. It might have to do with a mod i just added, but idk. The mod list is here: https://pastebin.com/wT282pJQ

The log says that you are using DS v3.4.9.9, not v3.4.9.12. Make sure it is updated correctly.

thats for the core mod, not the actual mod version, unless that isnt updated along with the new version, because I AM using the latest version.

Core mod is not separate - it is actually part of the JAR itself.

Also, from your posted modlist:

    | UCHIJA | dsurround                 | 3.4.9.9                      | DynamicSurroundings-1.12.2-3.4.9.9.jar               | 7a2128d395ad96ceb9d9030fbd41d035b435753a |

Right - its version 3.4.9.9. Latest released version is 3.4.9.12.

The Forge version you list about would not be compatible with 3.4.9.9. Reason is that Forge now has the ASM patches for sound engine crashes that are present in DS 3.4.9.9. This causes a conflict which could result in the error you linked. The release version of DS conditionally applies this patch based on the Forge version installed.

I just redownloaded and reinstalled the mod into my pack, and it seems to have worked just fine. I must have had a faulty mod version or something. Just to note, I DID remove betweenlands (which adds sound), tinkers and its addons, smoothfont, thaumcraft, agricraft, and astral sorcery if that might have caused it.