iTunes Sound Check: Normalize The Loundness of Songs

Cure annoying volume differences between songs in iTunes

iTunes Sound Check
Sound Check option in iTunes preferences. Image © Mark Harris - Licensed to About.com, Inc.

How Does iTunes Sound Check Work?

Are you frustrated by the volume differences between songs in your iTunes library? If you find that they all play at different volumes, then using the iTunes Sound Check feature could be all that is needed to solve this common problem.

To try and resolve the issue of volume differences between tracks, Apple has included this feature but it is disabled by default. Without going into too much detail, this option scans the contents of your music library to measure the relative differences in loudness between all songs.

It then computes a playback volume level for each file (a normalization value) which is usually stored in the metadata of the digital audio file -- this is similar to how ReplayGain works in fact.

The great thing about this method of sound normalization is the contents of audio files remains untouched. You therefore don't have to worry about backing up your iTunes library -- although it's always best before making any changes.

This non-destructive approach means that disabling Sound Check will return all your songs to their original loudness volumes.

But, why do some songs play much louder or quieter than the rest?

If you have used several music sources to build up your iTunes library (e.g. online music services, ripping your audio CDs, recording live performances, etc.), then there is a high probability that the volume levels between each file will vary -- sometimes enormously! This can spoil an otherwise great listening experience when you have to continually play around with the volume controls in iTunes or on your speaker system.

To configure Sound Check in iTunes, follow the steps below for your operating system (PC or Mac OS X):

For the PC version of iTunes

  1. Click the Edit menu tab on the main iTunes screen.
  2. On the pop-up menu that appears, choose the Preferences option.
  3. Click the Playback menu tab.
  4. Enable the Sound Check option by clicking the check box next to it.
  1. Click OK to save the settings.

For the Mac OS X version of iTunes

  1. Click the iTunes menu tab on the main screen.
  2. Choose the Preferences menu option on the pop-up screen that appears.
  3. On the main preferences screen, click the Playback menu tab.
  4. Click the check box next to the Sound Check option to enable it.
  5. Click OK to save settings.

Tip:

  • If you want to see the volume adjustment Sound Check has applied to a particular song, right-click one of them in your iTunes music library list and choose the Get Info option. You will see the normalization amount (measured in dB) next to Volume in the summary section.