After a lot research inside this site, i found an excellent comment that saves my day here: "Now that I've removed the AVEncoderBitRateKey and value, it also works on the 5S."
So, i just comment this row and fix it !!
[recordSettings setObject:[NSNumber numberWithInt:16] forKey:AVEncoderBitRateKey];
I can hear again the record sound in iPad Air ! Why happen this? I did not know yet, but its works and maybe you have the same problem and just want to leave a log about this case in this website.