While i haven't tried it myself, i'd imagine you can. You'd just need to create the same folder structure as textures and have the right filename. Though, i don't know if it would be picky at all about length and whatnot. Someone made a pack that changes a hurt sound so i think *some* sound modification is possible
I was curious about this too, so I decide to try it out.
I tried replacing the sound that plays when you cast the Razorblade Typhoon spell but all that did was mute the casting sound.
I made a simple texture pack folder with the folder structure: "Content/Sounds"
I downloaded TConvert and converted a 1 second long .mp3 sound effect and converted it to .xnb and placed inside /Sounds, replacing Item_84.xnb.
Clearly something happened since the sound is mute now but maybe I need to do more than just convert it so the sound so it actually plays properly, but who knows.
Funny enough, replacing the sound directly works just fine.
It might need to be the same filesize or length. kinda similar to how texture packs require specific dimensions. And if it were to work in texture/resource packs, it might need to be a specific filetype. Like .wav or .mp3 maybe? It'd be nice to get some official word on this. If we have potential full on resource packs and not specifically textures, things could get awesome.
A simple Tutorial on how to change Audio in a resource pack: 1. Find the file that you want to change, and put it in a folder in your Resource Pack's Content folder called Sounds. On Windows, the place that you can find the vanilla sound files should be here...