Audio buffs are familiar with graphic equalizers, devices that change the relative volume of different frequency ranges of music. While one should never have to do this, if the music is engineered correctly, and if you’re listening on a good stereo, differences in rooms, or in your ears, may lead you to want to increase bass or treble, or dampen midranges and lower extremes. (One valid reason to use EQ is to boost treble for those with high-frequency hearing loss.)
You can make detailed changes to music playback with an equalizer, and the digital equalizer in iTunes – available by choosing Window > Equalizer – reproduces these features. You can use the pop-up menu to choose presets for different types of music or speakers and to make a preset of your own custom settings.
There are 22 equalizer presets, from Acoustic to Vocal Booster. Each of these presets changes the relative volume of a band of music around the frequency shown at the bottom of each slider. So the first slider affects music around 32 Hz; most likely from 32 to 64 Hz, but the boundaries are never that precise.
In addition, there is a Preamp setting which increases the gain (volume) of the music. You don’t want to apply this across the board, but if you have some music that’s very soft or loud, you can apply this setting to individual songs.
First, try using the equalizer for your playback. Start with the Flat preset, then click On. Try other presets; it’ll take a second for iTunes to make the change as you switch from one to another. See if you hear a big difference in sound, and if the sound is better. Then try with other types of music. What you’re looking for here is a compensation for your speakers, your room or your hearing.
The presets are, however, somewhat confusing. Why is a given preset Classical and another Electronic? If you look at several of them, you can see there’s only a tiny difference:
The four presets above are for different types of music, yet their curves are very similar. It’s safe to assume that the named presets have nothing to do with the type of music they represent; they just give users something to play with.
However, the Pop and Rock presets are very different; almost mirror images of each other. For Pop, this suggests that you want to increase the midrange, where the vocals are; for Rock, it suggests you want to diminish the vocals.
If you find that certain settings help improve your sound – correcting for deficiencies in your speakers, or compensating for the sound of your listening room – you should try and create your own preset. Do this by changing any of the settings, then clicking the popup menu and choosing Make Preset.
It’s unlikely that the lowest or highest sliders will have much effect. If you don’t have a sub-woofer, your speakers probably don’t play frequencies low enough to be affected, and you won’t hear much at the highest end of the spectrum. But try different settings, with different music, and see if it sounds better. If it does, take some time to live with it, then switch back to Flat every now and then and see if the other preset still sounds better. Don’t expect to find the right settings right away, and you may decide that it’s best to leave the equalizer turned off.
As I said above, you can apply equalizer presets to individual songs. Select a track, or a group of tracks, then press Command-I; click the Options tab and choose a preset from the popup menu. If you choose one of the built-in presets, this will carry over to any iOS device where you sync the songs; your manual presets will not. (This assumes that you turn on EQ in Settings > Music.)
I’ve found that while the equalizer does alter the bass or treble a bit, in many cases it also distorts music. If you don’t like the way your music sounds, especially if you have small speakers or cheap headphones, give it a try, but don’t expect miracles.
??Bonus: if you want to see the actual frequencies of your music, check out the LED Spectrum Analyzer visualizer plug-in for iTunes. It shows you something like this, and changes in real time: