The Sound Test is a subject that appears in the Sonic the Hedgehog series. It is a feature where the player is able to listen to most music and sound effects from the game.
The Sound Test is an in-game audio player feature that contains various audio tracks ranging from background music, sound effects and character voice lines of that game. It can also feature music that is not heard anywhere else in the game.
In earlier games for the Sega Mega Drive, the Sound Test is a hidden feature and is often integrated with the Level Select. Like Level Select or Debug Mode, it is accessed by inputting certain actions, which has to be done on a certain part of the game to do so. In modern Sonic games, the player usually needs to fulfil certain in-game requirements for the Sound Test and its tracks to be unlocked though they can be available from the beginning of some games as well.
The Sound Test can also be used to activate other hidden features in actual gameplay or reveal hidden content. In the earlier main games, this comes in the form of playing certain tracks in a specific order; most of such sequences tend to reference various subjects such as dates.
One of the first games in the series to feature Sound Test at options is Sonic the Hedgehog 2, while later other games such as Genesis versions of Sonic the Hedgehog Spinball and Sonic 3D Blast it is available in the options menu. As before mentioned games have Sound Test being normally featured, they have been also part of the those games' hidden Level Select menu. In Sonic the Hedgehog CD, if the game has been completed by getting its good ending, the player unlocks a feature called D.A. Garden from the title screen of the game, which includes the Sound Test and being able to see Little Planet in different timelines. However, the past tracks are absent. The normal, yet hidden Sound Test can be found by using cheat codes, which also includes sound effects and the past tracks. Knuckles' Chaotix version of Sound Test features more complex system, with being able to test different audio modes. By getting this, the player has to configure the certain codes on each two above sets on the Color Test by entering "06", "0B" and "11" on the second set of digits, making 1971 beside the "Mars". In Sonic Jam, the player can play music tracks and sounds effects at the Sonic World's "Music Shop", which are taken from the original Sonic the Hedgehog, Sonic the Hedgehog 2 and Sonic the Hedgehog 3 & Knuckles.
In later games such as Sonic Adventure, Sonic Adventure 2, Sonic Heroes and Sonic the Hedgehog (2006) (in the latter being dubbed as Music Room), the Sound Test has become an extra feature, which can normally be found at the Options menu of the game. In Sonic Advance, there is a Sound Test that can be used from the beginning of the game, but in Sonic Advance 2 and Sonic Advance 3, the player has to unlock it after clearing the game a certain way. In Sonic Unleashed, collecting Records will let the player listen to the music tracks from the game on the Gramophone or Audio System. In Sonic Riders, Sonic Riders: Zero Gravity and Sonic Free Riders, it is unlocked after completing the games. In Sonic the Hedgehog Genesis, a similar feature known as the Juke Box is added, which is unlocked after beating the game with all six Chaos Emeralds collected. In Sonic Mania and Sonic Mania Plus, the Sound Test is included within the hidden Level Select. The DA Garden from Sonic the Hedgehog CD also comes back, being featured as an extra mode.
- In Knuckles' Chaotix, by entering "00", "08" and "17" in the third set under the title "Mars", 0117 should be reading on number beside at the Color Test, and Amy Rose will make a cameo dancing and saying "Cool, sweet & catchy!".
- In the Sound Test of Sonic Chaos, if the player moves in a forward quarter circle motion (down, down-left and left) and presses or , Sonic can be seen shooting out a sparkling fireball, resembling the Hadoken from the Street Fighter series.