Hello king7alok,
Getting the volume that's expected from your iPhone receive is important. If you haven't already, you'll want to complete the steps listed below as they're specific to resolving audio quality issues with the speaker and receive. You can also find these steps outlined in the following article, along with additional steps that can be helpful.
- "Remove all screen protectors, films, or cases from your device.
- Check the speaker opening to see if it's blocked or dirty. On iPhone only, make sure that the receiver isn't blocked or dirty.
- If necessary, clean the speaker or receiver opening with a small, soft-bristled brush. Make sure that the brush is clean and dry.
- Go to Settings > Sounds (or Settings > Sounds & Haptics), and drag the Ringer and Alerts slider back and forth a few times. If you don't hear any sound, or if your speaker button on the Ringer and Alerts slider is dimmed, your speaker might need service.
- If you hear sound, try making a call with your iPhone and turn on speakerphone. On iPad or iPod touch, make a FaceTime call. If you still can't hear, or hear static or crackling, then your network or reception could be the issue. Try to call again later, or from a different location."
If you hear no sound or distorted sound from your iPhone, iPad, or iPod touch speaker - Apple Support
Let us know how that goes!