Hi, Firstly i would like to say sorry if there's a similar topic before. Just purchased an iphone 5s yesterday and i noticed there's a strange loud sound with the keyboard click when i was typing. I was in the middle of a conversation in whatsapp, and when i typed in some letters, the keyboard click tends to be quite loud and then back to normal again. i noticed that it will turn loud if i type in some letters and receive a message at the same time and then the clicking volume back to normal again. What causes this btw? Thank you very much for your help and thoughts!