[AC Question]

Make volume louder

[B. Diddy]

Welcome to Android Central! There are a number of "volume booster" apps on Google Play, but I'm not sure if they truly work. You could give them a try.

[kramer5150]

If your phone has a volume limiter there might be a way to defeat it. The EU version Sony Z3 was notorious for this.

Switch to more sensitive / efficient headphones.
Switch to closed headphones, sound isolating in-ear types will work best. This will help block out ambient noise.
You can add a headphone amp, although that won't be your most practical option.

[Mooncatt]

Even *if* you find an app that can boost the volume more, you run the risk of blowing the phone's speaker due to increased distortion. When you over drive an amplifier, even the small ones in phones, you cause it to start clipping the audio signal. Without getting too technical, that's what causes distortion you hear and is one of the most damaging things you can do to a speaker.

I wouldn't suggest trying to boost the volume beyond the factory abilities.