Is there a way to improve the audio output of an iPhone?

The EQ settings on iPhone don't do very much. I personally use Bluetooth Headphones from Parrot Zik, which offers an amazing equalizer in their app. This is a costly, but very satisfying option. That said, you could try an equalizer app from the App Store. Here's an article I found which lists some: The Best EQ Apps for iPhone/iPad: Control Your Music The Way You Want

richard a. wrote:

Is there a way to improve the audio output of an iPhone so that music sounds better in headphones?

You can try settings - music - EQ