They dont seem to work in multiplayer.. why? does it work in sp? i havent tried but for the saving private ryan i do hear the sounds different at multiplayer menu.
sound mods are just that, mods. Most servers in the world run with sv_pure 1, which means that the game forces clients to use the stock sounds, skins, wepons, models, scripts. If a server either runs teh mod or has sv_pure 0, then your mods will work, except weapons, scripts and menus. Custom skins and sounds work with sv_pure 0.