How to increase quality of speaker

@aman9128 you are not telling us what the exact model for your phone is. You are also not telling us if this is a new problem, or if this is something new.

You want to make sure that you have all the settings adjusted so that we can rule out a software issue. If all of those settings are properly adjusted, then the issue could be a dodgy speaker. You can always replace it with a new one. If it has always been doing this, so if this is not a new problem than your expectations for the quality of the speaker maybe to high. It could just be a mediocre speaker system that is just not of the highest quality. That can't be fixed.