Get help with the microphones on your iPhone, iPad, and iPod touch - Apple Support
The article above is not correct! I just tested and speakerphone obviously uses the rear microphone and Siri uses the front receiver.
iPhone 6, iOS 9.0.2, null
Posted on Mar 30, 2016 1:48 AM
Q: This article is not correct! I just tested and speakerphone obviously uses the rear microphone and Siri uses the front receiver.
Or there is something wrong with your iPhone.
http://www.apple.com/feedback/iphone.html