How to customize iPod EQ using iTunes:
In iTunes menu bar, select Window - then - Equalizer
Customize EQ settings to your liking.
(As soon as you change any EQ passband, the name of whatever preset you started out with, will change to "Manual" in the pulldown menu at the top of the EQ popup screen)
Strongly recommend that you use subtractive EQ ONLY!
Increasing any passband above 0db setting (on any iPod I've ever owned) degrades the sound quality way more than subtractive EQ.
The only thing that matters in EQ is the "shape" of your EQ settings (i.e. bandpass gain settings RELATIVE to each other), not their absolute amplitude.
Now, the important part:
- In the iTunes / Equalizer pulldown menu, that now says Manual, select "MAKE PRESET".
- Type in an EXISTING preset name: e.g. Rock
You'll get a prompt saying: "An EQ preset already exists with the name "Rock". Do you want to overwrite it? -Click YES!
- In iTunes, be sure you have Equalizer selected in View Options, for the Playlist to which you will be applying your custom EQ.
- select the Preset Name (e.g. Rock) that you used for your "Custom EQ" for the each track you want to listen to, with your new custom EQ.
- Select the same EQ Preset Name on your iPod (in the Settings / EQ menu).
Voila - you now have a custom EQ on your iPod (you have customized a preset EQ)
You can now iterate: make incremental changes in your custom EQ setting in iTunes (as described above),
sync your iPod,
listen,
and then modify your Custom EQ appropriately,
until you zero in on the ideal EQ for you ears & your system.
I couldn't live without it.
But never, ever, exceed 0db on an iPod EQ setting.
PS: I create & save an EQ setting named for each headphone (e.g. W3, SE530), then just overwrite "Rock" with the EQ setting saved for whatever headphone I'm listening to.