Q: Sound failure on iPad Air 2?

I'm having the same problem, hovewer this started with my previous iPad Air. I've been having all the iPads starting from the iPad 3. The speaker issue you described above, I expereinced with the first generation iPad Air (5th gen. iPad). Whenever that popping buzz sound occured the iPad was silent until a reboot. I thought it was a hardware issue. Time passed and I was too busy to take it to an Apple store to get it replaced. Then I bought an iPad Air 2 and gave the Air 1 with the speaker problem to my sister. I transfered all my data to the new iPad via iCloud. At the very first moment after the iCloud restore finished and I touched the screen to enter my passcode, the speaker on the all new iPad Air 2 popped. I had to reboot it three times to get the speakers work again. Usually the speakers pops about once or two times in two weeks.

The interesting thing is that my sister have been using my old iPad Air since I got the Air 2 and she haven't experienced this speaker issue yet. I assume that this problem is a software-related issue since it transferred to my new iPad via the iCloud backup.

This as the first helpful post I've been able to find.  Thank you so much!