I am having a strange notification/sound glitch with my iPhone 5s running ios 8.1.2 (but had the same problem with 8.1.1). What happens is this....I'll have my iPhone sitting on my desk with the screen up. Occasionally the screen will "wake up" for some notification and the notification sound is just a small blip, like the speaker is going out/defective, but there is no notification displayed on the lock screen. I'll pull down the notification center to try and see what notification (which app) may have generated the notification but I am unable to tell. In other words, if this happens at 10:15 for example, there is no notification that appears to have occurred at 10:15. I have gone thru all the apps for which I receive push notifications to check my settings, but it's nearly impossible to tell which app(s) is causing this issue. This problem is intermittent, like 3-5 times per week, and seems to have started a month or so ago. This past weekend I upgraded to ios 8.1.2, then reset all device settings and re-configured everything, but I am still having the same problem. The only thing I haven't tried is a complete restore then set up iPhone as new. My speaker seems to work just fine for calls, music, etc. The only time I notice any sort of weird noises/sounds is when this happens. Has anyone seen this before? Suggestions?