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Sirenfall, a civil defense siren synthesized in Web Audio

Details

External ID
49556678
Source
HN
Company
—
Product
Sirenfall, a civil defense siren synthesized in Web Audio
Website domain
sirenfall.live
Launched
Sept. 3, 2026
Cohort
—
Upvotes
5
Upvotes percentile
0.12998405103668262
Tags
—
Fetched at
Sept. 10, 2026, 5:31 a.m.
Updated at
Sept. 10, 2026, 5:31 a.m.

Description

I built a cool browser scene, a shelter window over a dystopian city in the rain. Pull the breaker and a siren tower spins up. The wind-down is super unsettling and I love it.The siren is not a recording. Two port rings make a 5:6 dual tone, 515 and 618 Hz. The horn turns at 4 RPM and everything (loudness, brightness, doppler and stereo position) follows the horn angle you can see on the tower. Rain and thunder are the only recordings.Build it yourself, source is one HTML file and MIT: https://github.com/beeswaxpat/sirenfallHow it works: https://sirenfall.live/how-it-worksPress F for fullscreen, S to save a picture. Landscape on phones. No cookies, no personal data, the only request besides audio is an anonymous page-count pixel.Appreciate any feedback and shoutout to the siren community!

Enrichment

Theme
audio utilities and sound management
Vertical
Government
Function
Hardware & robotics
Audience
B2C
AI stance
Not AI
Project type
Hobby / open-source project
Normalized one-liner
civil defense siren audio tool
Manually corrected
False

Could you build this?

Partial The visual shelter scene is simple canvas/CSS, but physically modeling a mechanical dual-tone siren's acoustic behavior and Doppler horn rotation purely via Web Audio synthesis requires specialized audio engineering.

What it would actually take: The implementation relies on the Web Audio API using custom AudioWorklet processors or oscillator nodes coupled with panners and bi-quad filters. The hard part is mathematical acoustic modeling: simulating air-flow chop across a dual-port rotor (5:6 frequency ratio), rotor inertia spin-up/spin-down curves, and rotational directional acoustic directivity (Doppler shift and HRTF panning). This requires digital audio signal processing and acoustic physics knowledge.

Discussion

2 comments analyzed.

Concerns raised: Sound output too clean and Hi-Fi, unrealistic for mechanical sirens, Missing mechanical distortion and wobble characteristics

Feature requests: Emulate spinning metal parts inertia and spin-up/spin-down behavior, Add mechanical distortion from vibrating parts, Implement realistic frequency wobble effects

Competitors

Other products that read as similar to this one — 59 launches clear the similarity bar, closest 8 shown.

Attention rank: #57 of 60 (itself plus its competitors, highest first — normalized so YC and Product Hunt are compared fairly).

Launched 309 days after the earliest competitor.

Other launches for this product

Same idea, different domain

Nobody's really built a hardware & robotics tool for Horizontal yet.