Music players, the good ones, have built-in equalizers. Normally, the equalizer is a one-size-fits-all setting. You can select any one type of sound to adjust for and the music will be balanced for it. Alternatively, you can usually set custom equalizer levels. Regardless if you use a preset or a custom setting, it will apply uniformly to all music. The one exception is iTunes. As terrible as iTunes is, it does a reasonably good job of writing metadata to your music files. If you use the app to sync your music, you can use it to specify equalizer settings per-song.
This works in the current version of iTunes as well as much older versions.
Equalizer Settings Per-Song
Open iTunes and go to your Music library. Select the Songs list view from the column on the left. Once you have all your songs listed, right-click the ‘Name’ field at the very top. A rather large menu of additional columns that you can enable will open. In this menu, look for and select the Equalizer option.
Once the Equalizer column has been enabled, you can specify equalizer settings per-song. Click the up/down button in the Equalizer column next to a song.
A menu will open listing all the different equalizer settings. Select the one that suits the song, and you’re done. Repeat for every single song in your music library. When you sync music to your iPhone or iPad, the equalizer settings will be written to the songs’ metadata and you will get a better listening experience on your device.
Unfortunately, there’s no option to set equalizer settings for multiple songs at once. If you have a large music library, you’re going to have to invest some time and set the equalizer for all songs, one-by-one.
An alternative method to specify equalizer settings per-song is to right-click a song and select the ‘Song info’ option from the context menu. On the song info window, select the ‘Options’ tab. At the bottom, you will see an ‘equalizer’ option with a dropdown that lets you pick one of the equalizer settings that iTunes supports.
We’d be lying if we said this second method is faster. Regardless which method you go with, it’s going to take time to do this for every single song in your library. If you’re not up to making the effort, set the equalizer for your favorite, most played songs which iTunes can identify for you.