How to access the iPhone Equalizer
If you ask me, the iPhone’s default audio settings are a little flat for music, but they’re easy to adjust thanks to the iPhone’s built in equalizer. It’s not an equalizer in the sense of manual sliders, but there are tons of preset options and you’ll certainly find one for your audio needs, whether you’re listening to ebooks, rock, or classical, or anything in between.
Accessing the iPhone Equalizer:
* Tap the ‘Settings’ icon (usually located on your Home screen, unless you moved it)
* Scroll down to and tap on ‘iPod’
* Now tap on ‘EQ’
* Scroll through the list to find the settings right for you
* Select the preset equalizer settings you want to use by tapping on them
* Exit the EQ settings by clicking the home button or by manually navigating out of the Settings
Note: I highly recommend having a song playing while you are trying out different EQ settings, the changes are different and you will immediately hear how each sounds.
You may want to change your iPhone’s equalizer settings to fit different audio output, for instance I use ‘Small Speakers’ when I’m using Apple’s earbuds, but I’ll use a more specific genre theme with higher quality headphones or my iPhone/iPod dock. It makes a surprisingly big difference, so play around and find one that works for you.
This same protocol works for adjusting the equalizer on every other Apple portable product, from the iPhone, 3GS, to the iPods.

Attention: Activating equalizer has serious impact on your battery lifetime!
It would be nice if the equalizzer could remember your prefered eq setting dending on the output device used
rgrds
Pascal
If you customize the equalizer setting in iTunes, those settings will carryover to the iPhone and you can enjoy the sound quality with the iPhone equalizer presets turned off.
I tried this, but not working in my Iphone
The settings don’t carryover to the iphone.
Sanjay,
Did you ever get your computer’s iTunes EQ settings to carry over to your iPhone? It’s not working for me so far.
Hi MMES,
Is that really works ? Can you describe me the steps more in detials ?
Thanks