It shouldn't be like that. What file formats? And how are you connected to the speakers (HDMI / S/PDIF / RCA)?
For individual files you can alter the audio offset in Kodi. Whilst playing a video bring up the playback menu (OK on remote or left click on mouse). Select the volume icon (third from right). The resultant menu has an 'audio offset' setting.
But there shouldn't be general sync problems except perhaps on old divx avi which has the occasional issue on all platforms.