What does the red light above the meters mean?
The ideal recording level is between -18dB and 0dB. You want as much of the meter to light up as possible, but you don’t want the red light at the top of the track to light up. This light means the input level has clipped. Clipping causes distortion, which sounds bad. There is no input level control on the iPhone. To get a lower level, you either have to reduce the volume of the thing you are recording, or point or move the microphone away from the sound source.
