As the inevitable and outstanding outcome of progress in science and technology, intelligent devices especially Apple iPhone provide great convenience for people's lives. Even though the device is equipped with the best configuration, it also can not avert the failure of certain functions. Actually, on every iPhone in use, there exist more or less problems. In recent times, iPhone users keep grumbling about iPhone call volume low that brings them considerable discomfort. If you happen to be the one with this trouble, you needn't fret as the following proposes 5 perfect solutions to it.