I've got my iPhone 5 switched on silent with vibrate enabled. I noticed this happen a couple times today, as I had my phone laying flat on my desk. When someone calls, the first 2 vibrate "rings" seem stronger, and the rest of them are audibly and noticeably softer, but remain consistent. Does anyone else notice this? Or is my phone faulty? Edit: Actually, the first vibrate is really strong. The second one sounds like its dying. The third and subsequent vibrates are softer but the same.