Lots of user are complaining that their new iphone 7 or 6s which were ealier able to give command from Siri and Sir was responding to it. But after someday they they found that Siri is not working and can't get siri to hear me. Actually when we press the home button to summon siri, the wave line moves a lot as if it was receiving a lot of noise and then goes off as if didn't recognize anything. This is surprising that Siri only works with headphones, but when once remove the earpods, siri cannot hear me neither the dictation works. So if we talk in details for different combination
Take iphone close to ear-> Siri works fine.
Use Earbud with iphone Siri work.
Use Bluetooth ->Siri works.
But if you use the Home button Siri does not seem to work.
General trouble shoot would be to make sure that:
1. Siri is setp up properly and activated
2. Hard Reboot the set and check if this fixed the issue.
3. Set the volume of Siri high.
4. Turn off DND. Check it works !
5. Restore the iphone from backup(iTunes or iCloud)
Else you can move with following solutions:
Fix 1: Restart Siri
Go to settings -> general->siri. Turn siri off click disable or whatever message pops up. Then double tap the home button and close settings. Reopen settings->general->siri-> Turn it back on. Then hold the home button and activate siri while in the siri settings.
Fix 2: Slap your iphone (Gently)
There are chances that iPhone software somehow triggered a recalibration of the mic. The mic was turned to the least sensitive level. The hardware is fine in the case and to fix the issue hold down the home button for Siri and as it is listening thump the bottom of your phone with your hand, just a few light slaps should do it.
Fix 3: Change settings
Another way to fix the issue
Fix 4: Check for hardware issue
Very likely the chances are that your iphone has a hardware fault in Mic. Even if your voice control is working but still Siri is facing hardware defect as it uses different logic with hardware operation. If there is a hardware problem with one of the microphonesm, you should get it checked at nearby Apple store and get a new pience in case the same is there.