Telephone app increases volume?

[iMore Question]

I am looking for an app that will allow me to increase the volume I hear on a phone call. My IPhone 5s volume is not as loud as my IPhone 4 was, when I am listening to a call. Thanks for the help.

 

[phreddyl]

Sorry there is no app to the best of my knowledge. I dont believe the volume has changed though- is the earpiece dirty?

 

[AgentHeracles]

Also, are your ears dirty. Earwax build-up does cause volume drop. (Don't be like Paddington Bear.)