How can I increase the volume on my iPhone 4?

[iMore Question]

When I use Google maps is very hard to hear the directions

 

[Just_Me_D]

Re: how can I increase volume on my iphone 4?

If you're using it in the vehicle, connect the phone to your hands-free system, if applicable, and then listen to the directions over your vehicle's speakers.

 

[David Day3]

it's relatively simple just hold the home button siri will come up adjust the volume