Q: Sound of conversation is too lov

Greetings hannafromdki,

Thanks for using the Apple Support Communities!

I understand that the volume coming from the receiver on your iPhone isn’t as loud as you would expect, even with the volume turned all the way up. To begin troubleshooting this situation, I recommend reading over and working through the suggested steps from the following article. 

If you can't hear a person on a call or voicemail or if the sound isn't clear on your iPhone - Apple Support

Have a great day!