How to Enable and Use Sound Check in iTunes

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Have you ever noticed that some songs in your iTunes library are quieter than others? Songs recorded today tend to be louder than songs recorded in the 1960s, for example. This is due to normal technological differences, but it can be annoying—especially if you’ve just turned the volume up to hear a quiet song and the next one half-deafens you.

Luckily, Apple built a tool into iTunes to solve this problem called Sound Check. It automatically makes all the songs in your iTunes library roughly the same volume so there's no more frantic dash for the volume button.

How Sound Check Works in iTunes

Every digital music file has what's called ID3 tags as part of it. ID3 tags are metadata attached to each song that provide additional information about it. They contain things like the name of the song and artist, album art, star ratings, and certain audio data.

The most important ID3 tag for Sound Check is called normalization information. It controls the volume at which the song plays. This is a variable setting that allows the song to play quieter or louder than its default volume.

Sound Check works by scanning the playback volume of all the songs in your iTunes library. By doing this, it can determine the rough average playback volume of all of your songs. iTunes then automatically adjusts the normalization information ID3 tag for each song to make its volume match the average of all of your songs. Voila: All songs play back at close to the same volume.

How to Enable Sound Check in iTunes

Turning on Sound Check in iTunes is very simple. Just follow these steps: 

  1. Launch iTunes on your Mac or PC.
  2. Open the Preferences window. On a Mac, do this by clicking the iTunes menu and then clicking Preferences. On Windows, click the Edit menu and click Preferences.
  3. In the window that pops up, select the Playback tab at the top.
  4. Check the box that reads Sound Check. Then click OK. This enables Sound Check and your songs will now playback at roughly the same volume.

Using Sound Check with iPhone and iPod touch

These days, most people probably don't do much music listening through iTunes. They're much more likely to use a mobile device like the iPhone or iPod touch. Luckily, Sound Check works on iPhone and iPod touch (and iPad), too.

Sound Check-Compatible File Types

Not every kind of digital music file is compatible with Sound Check. In fact, iTunes can play some file types that can't be controlled by Sound Check, which could lead to some confusion. The most common music file types are all compatible, so most people will be able to use the feature with their music. Sound Check works on the following digital music file types:

  • AAC (the default format for the iTunes Store and Apple Music)
  • AIFF
  • MP3
  • WAV.

As long as your songs are in these file types, Sound Check works with songs ripped from CD, bought from online music stores, or streamed via Apple Music.

Does Sound Check Change My Music Files?

You might be worried that Sound Check changing the volume of songs means that the audio files themselves are being edited. Rest easy: that's not how Sound Check works.

Think of it this way: every song has a default volume—the volume at which the song was recorded and released. iTunes doesn't change that. Instead, the normalization information ID3 tag mentioned earlier acts like a filter applied to the volume. The filter controls the volume temporarily during playback, but it doesn't change the underlying file itself. It's basically like iTunes turns up its own volume.

If you turn Sound Check off, all of your music will go back to its original volume, with no permanent changes.

Other Ways to Adjust Music Playback in iTunes 

Sound Check isn't the only way to adjust the playback of music in iTunes. You can adjust how all songs sound with iTunes' Equalizer or individual songs by editing their ID3 tags.

The Equalizer lets you adjust how all songs sound when you play them by boosting bass, changing treble, and more. This is best used by people who understand audio pretty well, but the tool also has some presets. These are designed to make specific kinds of music—Hip Hop, Classical, etc.—sound better. Access the Equalizer by clicking the Window menu, then Equalizer.

You can also adjust the volume levels of individual songs. Just like with Sound Check, this changes the ID3 tag for the song's volume, not the file itself. If you prefer just some changes, rather than changing your entire library, try this:

  1. Find the song you whose volume you want to change.
  2. Click the ... (three dots) icon next to it.
  3. Click Get Info.
  4. Click the Options tab.
  5. In it, move the volume adjust the slider to make the song louder or quieter.
  6. Click OK to save your change.