iPhone 4 Audio and Frequency Response Limitations

The iPad’s lack of line level audio input support via the dock connector certainly raised the question of what would be in store for the iPhone 4. Now that I have my hands on the new iPhone, I thought I would go ahead and report on the state of audio I/O on the new device.

Here’s what seems pretty clear, based on my initial tests of the iPhone 4:

  • The iPhone 4 does not accept standard iPod accessories with line level input
  • Unfortunately, the new iPhone doesn’t work with the USB connector of the iPad camera connection kit, either, so there really isn’t a two-channel audio input option at the present time.
  • The frequency response of the iPhone 4’s headset mic input is virtually identical to that of the iPhone 3GS.
  • The built-in microphone’s frequency response also closely matches that of the 3GS.

iPhone 4 Headset Input Frequency Response

iPhone 4 Built-in Microphone Frequency Response

It really is unfortunate that there is currently no way to get stereo signals into the new iPhone 4, although I’m confident that it’s only a matter of time before an acceptable solution presents itself. Beyond this glaring limitation, the iPhone 4 is essentially the same as the iPhone 3GS (and iPad) in terms of its audio performance. It will be interesting to see, though, what new possibilities open up with the A4 processor, the increased memory, and the high-resolution display (which is quite amazing, by the way).