Definition

The Alarm pattern is a set of auditory cues that humans and animals use to communicate fear. Screams, shrieks, sirens, squeals, and yelps all share a set of distinct acoustic features. These features are difficult to produce, which helps alarm cues serve as honest signals of danger (avoiding the boy-who-cried-wolf problem). The more abruptly artists introduce alarm cues into their music, and the more performers intensify the unique features that distinguish them, the more likely we are to experience chills. 

Listen to examples below  ▾   

Mechanism

The Alarm pattern directly activates our amygdala (a brain region that helps us respond to threats). Alarm cues have two key features. First, they concentrate energy in the 3-5 kHz range. This mirrors the resonant cavity of our ear dream and is the part of the audio spectrum to which we are most sensitive. Sounds in this range are especially piercing; opera singers use a squillo technique that brings out a “singer’s formant” around 2.8-3.2 kHz, which helps them project over an orchestra but is also likely why some people say opera sounds like screaming. A second distinguishing feature of alarm cues is rapid amplitude modulation. Whereas normal speech modulates at a rate of 4-5 Hz/sec, screams modulate at 30-150 Hz/sec. This helps makes them especially attention-grabbing.

Technique #1: “Noisy” high-pitch sounds with spectral non-linearities

Listen to examples below ▾

The first Alarm technique involves “noisy” distortions (sidebands, warbles, or chaotic broadband energy between and outside the normal harmonics of a sound source) that occur when a resonator is strained above its natural range. In chills-inducing passages, the most reliable ways we see artists pull this off are

In chills-inducing passages, the most reliable ways we see artists pull off this technique are:

• Vocals: where talented singers achieve authentic, atonal screams that produce significant white noise (chaotic broadband energy), or when an artist includes a sample of a person screaming in real life 

• Instruments: where musicians produce non-linearities by applying too much bow pressure close to the bridge on string instruments (“screeches”, esp. on violins), by “overblowing” reed instruments and causing the pitch to jump an octave (esp. clarinets, flutes and piccolos), by causing “squeals” on brass instruments (esp. trumpets), and by featuring certain metallic percussion instruments that resonate at inharmonic overtones (esp. waterphone, anvil, cymbals, and gongs)

• Production and samples: where an artist produces non-linearities by adding distortion to electronic instruments at high pitch (esp. guitars and pads), creates dissonant guitar-amplifier feedback, or features of samples of animal distress calls

Don’t interpret this technique as a “hack” that automatically results in chills. Just having a vocalist scream as high as they can won’t work. Whether listeners experience frisson depends on the preceding context and the onset, intensity, and variation of the non-linearities. Artistry is required in the set-up, follow-up, and execution. Consult the Frisson 101 page for tips on how other artists have used this technique.

Technique #2: High pitch with rapid amplitude modulation 

Listen to examples below ▾

The second Alarm technique involves high-pitch sounds with a frequency feature called acoustic “roughness” (rapid fluctuations in loudness, 30-150Hz vs. 4 Hz for normal speech) that we perceive as beating or rattling. In chills-inducing passages, the most reliable ways we see artists pull this off are:

• Single high-roughness tones: where an artist features a timbre with an especially high modulation rate, including tonal screams in lead vocals, electronic tremolo effects on guitar, organ, or pads, flutter tongue on wind and brass instruments, tremolo bowing on string instruments, or percussion instruments like the ratchet 

• Two interfering tones: where an artist features two simultaneous tones a minors second, tritone, or major seventh apart that produce an irregular “beating” effect, typically sounded in the same octave as held chords or rapid trills and embellished with doubling and reverb so the tones interfere as much as possible

• Many staggered sound sources: where an artist features one section in which each player sounds high-pitched notes randomly and independently (esp. plucked high notes on strings or wordless chorus), resulting in an overall chaotic and irregular sound that produces acoustic roughness

Technique #3: Whistles and whistle register

Listen to examples below ▾                                                                                                              

The third Alarm technique involves whistle-like sounds with high, pure pitch and concentrated energy in upper frequencies. In chills-inducing passages, the most reliable ways we see artists pull off this technique are:

• Vocals: where an artist uses the whistle register above falsetto, typically achieved by female pop singers and coloratura classical sopranos and sounded during quiet, low-energy passages when the contrast of the sudden high note is as jarring as possible for listeners

• Instruments: when an artist features high notes on fipple flutes, including tin whistles, recorders, Native American flutes, and other wind instruments with similar constricted mouthpiece, typically sounded with moderate dynamics to avoid overblowing the instrument and creating too shrill of a sound

• Production and samples: when an artist features recordings of air or steam whistles or creates whistle-like, electronic instruments, typically used sparingly in the latter parts of songs to add intensity to a climax or end of a well-signaled cadence when listeners are distracted by the harmonic movement

Technique #4: Certain arcing pitch contours (“sirens”)

Listen to examples below ▾                                                                                                              

The fourth Alarm technique involves certain gliding notes with an arced rise-and-fall contour and pronounced peak. In chills-inducing passages, the most reliable ways we see artists pull off this technique are:

• Fast, high sirens: when an artist features a gliding note from medium to high pitch, with an abrupt entrance, loud dynamics, non-linear acceleration, and where the majority of the acoustic energy is concentrated in the peak rather than the rise or fall (think faster police sirens vs. slower air raid sirens)

• Slow, low sirens: where an artist features a gliding note moving from low to medium pitch, with a legato entrance, muted dynamics, linear rise and fall, and where the majority of the acoustic energy is spent in the rise and fall rather than on the peak itself (think slower air raid sirens as opposed to faster police sirens)

Technique #5: Certain upward, concentrated frequency shifts

Listen to examples below ▾

The fifth Aggression technique involves certain upward frequency shifts that concentrate acoustic energy in the 2.8-3.5 kHz range (the resonant cavity of the human ear drum). In chills-inducing passages, the most reliable ways we see artists pull this off are:

• High-brightness timbres: when an artist features singers using squillo technique (where a vocalist brings out a formant right around 3,000 Hz), certain wind instruments like bagpipes, certain brass instruments like bugle or piccolo trumpet, or uses formant-shifter plugins, all on notes that have a high – but not too high – fundamental frequency given that singers tend to lose their formants at the top of their range

• Embellishment with leaps and phrasing: where an artist introduces an upward frequency shift at the peak of a melodic line, the climax after a build-up, or an octave leap after a relatively quiet, sparse section to make the contrast of the high-pitch entrance as prominent and jarring as possible for listeners