I have been trying to research this but can not find an exact way to fix the low vibration or lack there of on my S5 for notifications and texts. Even if it is on my coffee table or sitting right next to me, I do not hear the phone vibrate! It appears as if in the Sounds section notifications and texts are set to silent. But when you use the button on the side and see that configuration it shows vibration. But the master seems to be over riding the feature. Thanks for your help!