I have asked the above question just to provide the answer for it because I myself was facing this issue.
I have an iPhone XR around two years old. I was facing this very low earpiece speaker volume issue while on call for some time.
And with it another issue was there that Siri wasn’t answering me when I was calling it. So I turned off it once and then when I tried to reset it at that time I wasn’t successful in doing its set up. While doing the set up when I was saying “Hey Siri” it wasn’t recognising me. Both of these issues are resolved now for me after clearing the earpiece speaker grill. Beacuse in an iPhone XR there is a microphone situated on the front speaker/earpiece speaker. That’s why Siri issue also got resloved automatically when the speaker grill got cleared. If you are also having the same issue, you can try the below method like me.
For me the cotton earbud method worked for solving it. If you also have the similar issue, just see at your earpiece speaker grill and if it is brownish in colour or silver in colour then it means it has some dust particles in it. It should be crystal black in colour. By looking at it externally I also thought that it didn’t have any dust particles in it because it looked clear to me but then when I started clearing it out using Cotton earbud then the dust particles were getting removed slowly and the speaker grill was turning in black colour it meant it was getting cleared and I was able to see the inside speaker that’s why it was appearing in black colour. But one important thing is there in this method that you need to be “PATIENT and GENTLE” in cleaning your earpiece speaker grill. What you have to do is to rub the cotton earbud gently and persistently on the earpiece grill. And in sometime you will see that the dust is getting removed and your speaker is getting cleared. For me it took around 20-30 minutes and three earbud sticks(each stick having cotton buds at its both the points). And meanwhile you can call yourself at regular intervals while cleaning the speaker grill and check if the call quality is getting improved or not. So it worked for me when I did it this way. You can also try it for yourself and check if it is working for your not.
I have seen a video on YouTube and in that video it was said that if your iPhone was dropped face down in that condition it happens that the speaker stops working sometimes. My iPhone also got dropped face down sometime back so I thought it was the issue but no it wasn’t the issue and just by removing the dust particles from the speaker grill it I was able to listen to the caller very clearly and loudly.
I want to mention one more thing. I think using any liquid or any sharp material to remove the dust particles or to clean your speaker grills is not the proper way because if we are not gentle in it we can end up damaging our speaker permanently so that’s why just use this cotton earbud method because it is the best I think.
