Input location of AVAudioSession are different between iPhone

Position of AVAudioSession is different when I use the speaker.

try session.setCategory(.playAndRecord, mode: .voiceChat, options:  [])
try session.overrideOutputAudioPort(.speaker)
try session.setActive(true)

let route = session.currentRoute
route.inputs.forEach{ input in
  print(input.selectedDataSource?.location)
}

In iPhone 11(iOS 17.5.1), AVAudioSessionLocation: Lower

In iPhone 7 Plus(iOS 15.8.2), AVAudioSessionLocation: Upper

What causes this difference in behavior?

Input location of AVAudioSession are different between iPhone
 
 
Q