While it lowers the volume of your footsteps to you, it does little to nothing for your enemies. Crouch walking can be heard up to 45m away and within 20m it sounds like normal walking.
https ://clips.twitch.tv/TriangularSmoggyHabaneroWholeWheat-vOBk5QoEg-3UgO6J
https ://clips.twitch.tv/RealFlaccidCrowPJSugar-JUbPis-0ybfesT2Y