There's a bunch of sound problems ever since EW launch since they overhauled the sound engine, from popping to flat out not even working at all. I doubt a reinstall on your end would do much sadly, you can try to read the other audio issues threads and try the possible fixes but they didn't seem to work for most people. I myself have a problem where half the sound effects just disappear during FATEs and hunts especially, and sometimes the game launches without any sound effects so I'm no stranger to this.