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 they should definitely be using.

Because songs are recorded at different volumes and with different technologies, the 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 it hurts your ears.

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

Turn On Sound Check on iPhone

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
  2. Tap Music
  3. Swipe down to the Playback section
  4. Move the Sound Check slider to on/green.

These steps work are based on iOS 9, but if you have an earlier version, 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/the Classic or 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

  1. Click the center button to select Settings

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

  3. 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 in this article.

How Sound Check Works

Sound Check sounds cool, but how does it work? Does it actually edit the MP3 files to change their volume? According to Apple, no.

Rather, Sound Check scans all of your music to understand its basic volume information. Each song has an ID3 tag that can control its volume level. Sound Check applies what it learns about average volume levels of your music and tweaks that ID3 tag to even out the sound. The ID3 tag is changed but the music file itself never is, so you can always go back to the song's original volume.

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.