How To Use Sound Check on iPhone and iPod

iPhone sound check
Protect your ears with Sound Check. Sean Gallup

Sound Check is one of those features most iPhone and iPod users don't know about, but that you should almost definitely be using.

Songs are recorded at different volumes and with different technologies (this is especially true of older recordings, which are often quieter than modern ones). Because of this, the default loudness that songs on your iPhone or iPod play at can be different. This can be annoying, especially if you just turned up the volume to hear a quiet song and the next one is so loud that it hurts your ears.

Sound Check can make all your songs play at roughly an equal volume. Even better, it's built into all recent iPhones and iPods. Here's how to use it.

Turn On Sound Check on iPhone and Other iOS Devices

To enable Sound Check to work on your iPhone (or any other iOS device, like the iPod touch or iPad), follow these steps:

  1. Tap the Settings app to open it
  2. Tap Music
  3. Scroll down to the Playback section
  4. Move the Sound Check slider to on/green.

These steps work are based on iOS 10, but the options are similar on earlier versions. Just look for the Music app settings and Sound Check should be easy to find.

Enable Sound Check on iPod Classic/Nano

For devices that don't run the iOS, like the original iPod line/iPod Classic or iPod nanos, the instructions are slightly different. This guide assumes you're using an iPod with a clickwheel. If your iPod has a touchscreen, like some later models of the iPod nano, adapting these instructions should be pretty intuitive.

  1. Use the clickhweel to navigate to the Settings menu

  2. Click the center button to select Settings

  3. Scroll about halfway down the Settings menu until you find Sound Check. Highlight it

  4. Click the iPod's center button and Sound Check should now read On.

Using Sound Check in iTunes and on iPod Shuffle

Sound Check isn't limited to mobile devices.

It also works with iTunes, too. And, if you noticed that the last tutorial didn't include the iPod Shuffle, don't worry. You use iTunes to enable Sound Check on the Shuffle.

Learn how to use Sound Check with iTunes and the iPod Shuffle in this article.

How to Enable Sound Check on 4th Gen. Apple TV

The Apple TV can be the center of a home stereo system thanks to its support for playing your iCloud Music Library or your Apple Music collection. Just like the other devices in this article, the 4th gen. Apple TV also supports Sound Check to even out the volume of your music. To enable Sound Check on the 4th gen. Apple TV, follow these steps:

  1. Select Settings
  2. Select Apps
  3. Select Music
  4. Highlight the Sound Check menu and click the remote control to toggle the menu to On.

How Sound Check Works

Sound Check sounds cool, but how does it work? Despite what the concept of the feature may make you think, according to Apple Sound Check does not actually edit the MP3 files to change their volume. 

Instead, Sound Check scans all of your music to understand its basic volume information. Each song has an ID3 tag (a kind of tag that contains metadata, or information, about the song) that can control its volume level.

Sound Check applies what it learns about average volume levels of your music and tweaks the ID3 tag of each song that needs to be changed to create a roughly even volume for all songs. The ID3 tag is changed to adjust the playback volume, but the music file itself never is changed. As a result, you can always go back to the song's original volume by turning off Sound Check.

Learn more about what ID3 tags are and what else they're used for in How To Change Artist Name, Genre and Other Song Info in iTunes.