Mic
The iPhone has multiple microphones placed around the device. REC allows you to choose which specific microphone to record from in order to capture audio from the direction you want. Available options depend on the device. We recommend you use the back microphone if you want the audio from the video subject to be heard, or the front microphone if you want to hear the voice of the cameraman.
External microphones can be connected either via a wired headset, or with a standard USB audio device. For phones with a Lightning port, you can use the Apple Camera Adapter to add a USB port to your iPhone.
Polar pattern
Depending on the microphone you selected, the iPhone can use its other microphones to apply noise cancellation and simulate different audio pickup patterns, or stereo sound.
- Omnidirectional – Capture sound from all directions equally. This records a mono audio channel.
- Subcardioid – Focus on capturing sound in front of the camera while still allowing in environment audio. This records a mono audio channel
- Cardiod – Focus more on sound in front of the camera, removing more environmental audio. This records a mono audio channel
- Stereo – Record stereo left and right audio using multiple microphones.
Mic Gain
When using certain external microphones, you can adjust the volume level of the microphone here. This will be disabled for the microphones internal to the iPhone.
Sample Rate
The sample rate determines how often the sound pressure level is recorded from the microphone. A standard sample rate means that the sound level is recorded 48,000 times per second! Nyquist theorem determines that the frequency of sound that can be reproduced is half of the sample rate, meaning that if you record at 48 KHz, the recording can capture a 24 KHz tone, which is at the upper limit of human hearing.
- 48 KHz is a standard sample rate for digital audio
- 44.1 KHz was the standard sample rate for CD audio and is still in common use
- 24 KHz is adequate to record human speech if you need to save on storage storage.
Format
- AAC is compressed audio (similar to MP3).
- PCM is lossless, uncompressed audio, which requires more storage space.