Lower speaker not working

Hi,

Phone audio systems have a range of potential fault areas.

Firstly the most common issue arises from the speaker grills getting a buildup of dust/fluff/lint &/or grime reducing the speakers ability to produce volume/sound.

You can visually inspect the grills to see if the holes are white, yellow, or ochre coloured - indicating that they are indeed blocked. You can lookup how to clean speakers on phone safely.

Another situation that could produce sound problems is the charging port has been damaged by water ingress that has affected sound operation, in this case the only solution would be to replace the charge port flex that houses the bottom speaker circuitry.

The worst situation is that an audio system IC has become faulty which would require micro soldering to rectify.

I would do basic fault finding by establishing if the audio system is functioning by testing if sound is reproduced in headphone and/or Bluetooth speakers, you can also test microphone by doing a voice recording and/or video recording to establish whether the microphones are working or not - in playback make sure the speaker isn’t muted, if you see the recording signal wave in playback but no sound then you know the microphone is working but speaker isn’t, which may indicate that it’s an audio IC fault.

After doing basic fault finding checks if you haven’t been able to resolve the issues then you may need to see a repair shop for assessment.

Hope this helps