Ambience (sometimes called cave noises) is a set of sounds that occasionally play when the player is in close proximity to a dark cave. They were made by C418, who also composed Minecraft's music. Ambient sounds can be played in any dimension, including the Nether and the End and can be heard in both singleplayer and multiplayer. Despite their name, they are not sounds that one would expect to hear inside of a cave, such as falling pebbles or dripping water, but rather supernatural noises frequently likened to demonic/ghostly moans, vehicles, ringing bells and instruments.
Ambient sounds can play in a space of any size, but they play much more likely in larger spaces positioned 10 - 20 blocks away from the player in any direction, and completely filled with a light level less than eight without any lighting from the sky (the ambience will more likely play from the direction of lower levels because of a lower light level). The space does not need to be sealed off - a sound can even play from a space that the player can actually see - nor does the player need to be underground to hear it. The sounds can also come from player-created spaces, even if that space is a box above the clouds.
 The Sounds
Ambient sounds are found in the resources/newsound/ambient/cave from the .minecraft folder. They play randomly in different pitches, like other sounds of Minecraft do. There are 13 sounds (Cave 1 - 13) in total:
- Trainhorn like sound
- Angelic singing
- Demonic roar
- Silent gong
- Menacing whiff or a Blaze breath
- Distant Airplane, or an Echoing Mine Cart
- Violin screech,Door creaking or a screaming Ghast
- Train passing by
- Loud bell
- Demonic grunt
Ambience was known to play only in 3x3x3 spaces or larger, but now they can be heard playing in 1x1x1 or larger spaces.
- Sometimes it doesn't matter how far the player is from the space.
- As of snapshot 12w07a, building height is increased, but dynamic lighting does not work above the old 128 block limit without blocks, causing ambience to play.
- Ambience can play anywhere in superflat worlds.
- Ambience is not an indicator of nearby ore, underground structures, mobs, etc. Following them can still lead the player to such things indirectly, since they emanate from unlit caves.
- Ambience can be used to detect areas where hostile mobs are able to spawn, since both require a light level of less than eight.
- Due to the unsettling atmosphere of ambience, these sounds can be frightening to some players. However, they do not represent any immediate danger. They only play in deep darkness. If you do not want to hear the sounds, light the caves you find (which is recommended, regardless, unless playing on Peaceful difficulty).
- Ambience can be disabled by turning off Ambient/Environment sound.
- Cave sound 8 resembles a stretched blaze sound. Although it sounds like there is one right around the corner, rest assured; rarely blazes can be encountered outside of the Nether unless it is spawned via spawn egg or third-party mod or traveled through a Nether Portal. Also, the sounds were implemented a while before blazes were.
- Ambience can play anywhere in The End.
- On rare occasions ambient noises can be heard if the player is standing by an ocean or deep body of water, regardless of light level outside the water. This is because deep bodies of water have very low light levels making this possible.