Reader Kirk Edgar Aplin asks a common question that, like an ill-favored cousin, I need to revisit from time to time. He writes:
How does the Equalizer setting in iTunes work? That is, does it alter the music file or merely the output when played through iTunes? Put it another way; do I have to worry about equalizer settings when I burn a playlist to CD?
Allow me to offer more answers than you’ve asked for.
To start with, there are two ways you can assign EQ to music in iTunes. The first is to assign a specific EQ setting to a specific track. You do this by selecting a track, pressing Command-I to bring up the track information window, clicking the Options tab, and choosing a preset from the Equalizer Preset pop-up menu. You can also assign a general EQ setting to everything that plays through iTunes. You do this by choosing Window -> Equalizer and selecting one of the EQ settings from the pop-up menu.
When you assign an EQ setting to a track or impose a general EQ setting, the tracks in your iTunes library are not altered—the tracks aren’t re-encoded or mucked with in any permanent way. Rather, EQ settings are instruction that tell iTunes or compatible devices which EQ setting to use (see the following exceptions). EQ settings are not maintained when you burn tracks to a CD. Instead, the tracks will be burned to the disc without any EQ enhancement.
Now, about EQ and those tracks on your iPod and iOS device. Your iPod, iPhone, and iPad will play tracks copied from iTunes with the EQ settings you’ve applied in iTunes (not the general setting but the EQ settings you’ve applied specifically to each track) as long as you haven’t configured the iPod or iOS device’s EQ settings to Off or Flat. Like so:
If the EQ setting is set to Off, the device uses no equalizer settings—all your music plays as it was originally encoded. Switching on EQ uses more battery power so Off is the setting to use when you want to save a little juice.
If you set the EQ settings to Flat, tracks that don’t have an EQ setting assigned to them play as originally encoded. If you’ve assigned an EQ preset to a track in iTunes, it will play using that preset.
But what happens when you go into the device’s EQ settings and choose one of the presets? In this case all tracks that don’t have an EQ preset assigned to them will use the setting that you’ve chosen on the device. So, choose the Rock preset on your iPhone and that’s the preset that will be used with these tracks. If you’ve assigned a preset in iTunes for a particular track, that track will play with that iTunes-assigned preset rather than the one chosen on the device.
However, you can override that iTunes-assigned preset. Just start playing the track on the device and then dash over to the device’s EQ settings and choose a different preset. The track will immediately use that setting. However (again), that preset doesn’t stick. When you next play the track, it will use the preset that you assigned in iTunes.
One more thing: Although you can create custom EQ presets in iTunes, those custom presets are not transferred to an iOS device. That device can use only those presets found on the device.