Mic quiet when on loudspeaker/Siri following screen replacementq

I Recently had to replace the screen on my iPhone 6 following it getting cracked. Everything works fine following that, except the second microphone only picks up sound quietly when using loudspeaker/Siri/recording video using front camera etc. Following internet searches it seems that It could simply be the mic is not quite in the right position but having had several attempts to rectify this it's no better. What does the microphone look like? Is it part of the Ear Speaker or part of the front camera flex cable?

Would be very grateful for any help as its annoying being unable to use Siri without headphones or make calls on loudspeaker.

Thanks in advance.