Noise

Version 0.33: This article is up to date for the latest stable release of Dungeon Crawl Stone Soup.

Noise in the dungeon can wake sleeping monsters. Monsters that hear a sound will generally wander toward it; if you get involved in a fight, monsters can come from all different directions to see what the fuss is about, potentially overwhelming you.

Noise meter

Under default settings, the information panel in the top-right of the screen shows a noise meter. The colour and length of the bar indicates the maximum loudness of noise heard at the player's tile on that turn. Thus most player causes of noise will be reflected at their maximum loudness on the noise meter, but the noise meter will show noise centered a few tiles away from the player at the loudness the player heard, not the maximum loudness of the effect.

The noise meter colours correspond to the following loudness values:

• White: 0-6: Noise at this loudness will not propagate far beyond the player's line of sight. Most melee and ranged attacks and low-level spells are in this category.
• Yellow: 7-13: Noise at this loudness will attract monsters from outside the player's line of sight. The most damaging melee and ranged attacks, shouting, and a number of mid-level spells are in this category.
• Red: 14-29: Loud noises that will awaken and attract monsters from a large portion of the current floor. Most explosive effects fall into this category.
• Magenta: 30+: The loudest noises in the dungeon, which will awaken virtually the entire floor. Only Shatter, alarm traps, and a few other particularly loud effects fall into this category.

Noise propagation

When a noisy action happens at a position, the noise will propagate to all the adjacent cells. Each time it advances a cell, the intensity suffers an attenuation. When the intensity reaches a value less than 1, the noise is inaudible and it won't propagate further.

The attenuation depends on the following factors:

• The cell type:

Cell type	Attenuation
Empty	-0.85
Statue or Idol	-1.70
Tree or Mangrove	-2.55
Closed door	-6.80
Wall	-10.20
Permanent wall	-infinity

This means that in open areas the radius of the area affected by a noise is: loudness/0.85 = loudness*1.176.

Ambient noise

Ambient noise makes sounds harder to hear. This idea is implemented in the game by adding, or subtracting, a branch-specific amount to loudness. The effective loudness is:

effective_loudness = loudness - sgn(ambient_noise)×{3d(abs(ambient_noise))/3 - 1}

The Swamp, the Shoals, and the Desolation of Salt are loud, with ambient noise +6. The Crypt, the Tomb of the Ancients, and the Slime Pits are quiet, with ambient noise -6. All other branches have ambient noise 0.

This effect is significant but not drastic. Shouts will not travel far in loud branches, whereas usually minor noises, such as attacking, may be sufficient to attract monsters in quiet branches.

Sources of noise

Melee combat

A successful stabbing is always silent. Otherwise, the loudness is equal to one quarter of the damage dealt, rounded down, with a minimum of 1 and a maximum of 12 (the player's normal shouting volume).

Ranged combat

There are two sources of noise when you shoot or throw a projectile: the launcher and the missile. The launcher or thrower makes noise of loudness 5 at their position, except for hand cannons which have loudness 10. The loudness of the projectile is one quarter of the damage dealt, which is always made at the projectile's final location, with the same minimum of 1 and maximum of 12 as melee combat.

Spell noise

See spell noise.

Player shouts

Different forms have different shouting volumes.

• Shouting in Bat Form, Bat Swarm Form, Fungus Form or Wisp Form has a loudness of 4
• Shouting in Spider Form or Scarab Form has a loudness of 8
• Shouting in Walking Scroll Form or Serpent Form has a loudness of 10
• Shouting in Dragon Form has a loudness of 18
• All player species and all other forms' shouting has a loudness of 12.

Additionally, each level of the Scream mutation adds 2 loudness.

Other sources

• Qazlal worshipper at piety ******: 16
• Scroll of noise: 25
• The Singing Sword: 0-35 depending on tension.
• Blocking an attack with the Shield of the Gong: 40
• Monster shouts
• Monster spells with the Noisy flag
• Creaking doors: 10 (1 in 8 + 4 * Stealth / 3); "As you open/close the door, it creaks loudly!")
• Alarm traps: 40
• Using the Horn of Geryon: 15

History

• Prior to 0.20, the player's gold was shown instead of the noise meter.
• Prior to 0.19, branch noise was more complicated. The Lair's ambient noise was 4, and the Orcish Mines's was 3.
• Prior to 0.13, the Crypt's ambient noise was -20.