So I installed a mod called Mutatis Mutandis from strategycore forum (seems I'm not allowed to post link but you can easily find it by navigate through strategycore forum) but after installed, the game don't have any music only FX and soldier sounds, music is back after I delete the mod. someone here also encountered the same problem (there is a post with the title "ufo aftermath no music is playing fx and speech unaffected") and and there is a possible solution with using "iso-program" or "virtual clone drive" but what does that ever mean? Something like Daemon Tools?
Also there is a tool for the game that allow running multiple mods called ALPine but I can't install it, the installer keep saying it could not find UFO Aftermath even when I put in the game directory.