🔬 The Science

How NightSnore
actually works.

Snoring has a unique acoustic fingerprint that decades of research has documented in detail. NightSnore pairs classic signal processing with an on-device AI sound classifier — the same deep-learning approach validated in peer-reviewed studies — running entirely on your iPhone, with no cloud, no account, and no subscription.

From microphone to morning report.

Every second you sleep, a quiet four-stage process runs in the background. Here's what happens.

🎧

Adaptive Noise Baseline

NightSnore continuously estimates your room's background noise throughout the night using a sliding-window percentile method. No 30-second wait — it adapts silently from the first moment and keeps adjusting as conditions change.

🎙️

Background Listening

Using iOS background audio, the microphone stays active while your screen is off. Audio is analyzed in real time; only short clips around detected sound events are ever saved — never the full night.

🤖

AI Sound Recognition

A neural network trained on millions of real-world sound samples scores each detected sound against more than 500 categories — telling snoring and related breathing sounds apart from everything else a bedroom produces.

📊

Morning Report

Events are grouped into episodes, a Snore Index is calculated, and a full timeline is assembled — ready for you to review the moment you wake up.

Snores don't sound like anything else.

Snoring is produced in the upper airway — the same part of your body that produces speech. This gives snores a characteristic quasi-harmonic structure: a low fundamental frequency (typically below 500 Hz) accompanied by a stack of overtones, much like a note played on a musical instrument.[1]

Bed shuffling, duvet rustling, and rolling over produce sounds that are completely different: short, percussive bursts with energy spread across all frequencies — more like a cymbal crash than a tone. This physical difference is exactly the kind of fingerprint NightSnore's AI model has learned to recognize.

Research confirms that snore events typically last between 0.3 and 3 seconds each.[2] NightSnore filters out sub-0.3-second transients — a door click, a phone bump against the nightstand — before they ever reach the classifier, so brief thumps don't pollute your report.

Frequency profiles
Snore — energy concentrated in low harmonics
Bed noise — energy spread across all frequencies
50–500 Hz — typical snore fundamental range
Harmonic structure — the vocal-tract signature the AI model keys on
Spectral shape — tonal snores stand apart from broadband bed noise
Detection pipeline
Stage 1 — Event detection
Lightweight signal processing tracks an adaptive noise floor for your room all night. Anything rising clearly above it becomes a candidate event.
Stage 2 — AI classification
An on-device neural network scores the sound against 500+ categories: snoring, a breathing-related sound, or something else entirely.
Snore decision
A sound counts as snoring if the AI is confident it's a snore — or if snore-related breathing sounds together tell the same story.
Post-processing
Nearby events are merged into episodes. Sounds the AI couldn't attribute to snoring aren't discarded — they're filed under "Other sounds" for you to review.

DSP finds the sound.
AI decides what it is.

Simple sound-level apps flag everything loud as a snore. That's why they pick up your partner shifting in bed, a truck driving past, or a door closing down the hall.

NightSnore splits the job in two — the same cascaded architecture recommended in academic sound-event detection research.[3] A lightweight signal-processing layer, built around an adaptive noise floor that quietly re-learns your room as conditions change, decides when something happened. Then an on-device neural network — trained on millions of real-world sound samples across more than 500 categories — decides what it was: a snore, a breathing-related sound, or just a creak, a cough, or a rustle.

The AI doesn't stop at the textbook snore, either. It also recognizes gasps, heavy breathing and other sounds that often surround snoring episodes, so quieter or fragmented events still get counted. And what it can't attribute to snoring isn't discarded — it's kept under "Other sounds" in your report, ready for you to review.

A number that actually means something.

NightSnore doesn't just count snore events — it calculates a Snore Index: the number of snore events per hour of sleep. This is the same basic metric used in clinical sleep monitoring, making your nightly score comparable across different session lengths.

Slept 4 hours instead of 8? The Snore Index still tells you the same thing about your snoring intensity. It's a rate, not a raw count — which makes trends over time meaningful even when nights vary.

Sessions shorter than 30 minutes are excluded from index calculation, since shorter recordings don't capture a full light-sleep cycle and can produce misleading results.

Snore Index reference ranges
Index Level What it means
< 10 Mild Occasional snoring; low impact on sleep quality
10 – 30 Moderate Frequent snoring; worth monitoring trends
> 30 Severe Very frequent snoring; consider consulting a doctor

For reference only. NightSnore is not a medical device and is not intended to diagnose sleep disorders.

Smartphone snore detection works.

Independent studies have validated microphone-based snore detection on smartphones across hundreds of participants and thousands of hours of sleep recordings.

~95%

Accuracy in controlled conditions

A CNN+RNN deep learning model for smartphone snore detection achieved ~95% accuracy, with ~92% sensitivity and ~98% specificity — and directly studied the effect of microphone placement distance.

Xie et al., Computer Methods and Programs in Biomedicine, 2020. doi:10.1016/j.cmpb.2020.105917

~90%

Sensitivity on real homes + hospital

A 2025 smartphone study using a Vision Transformer, validated on both hospital and home recordings across hundreds of participants, reported sensitivity and specificity around 90% on a held-out test set.

Hong et al., Nature and Science of Sleep, 2025. doi:10.2147/NSS.S514631

~99%

Specificity for non-snore sounds

A 2025 independent benchmark of a commercial snore-detection algorithm found ~86% sensitivity and ~99% specificity on a diverse test set including simulated non-snoring files — meaning very few false alarms.

Brown et al., JMIR mHealth and uHealth, 2025. doi:10.2196/67861

These figures are from independent academic studies, not NightSnore's own testing. Real-world accuracy depends on phone placement, room acoustics, and individual snoring patterns. NightSnore is built on the same class of on-device deep-learning audio classification validated in this research.

🔒

All of this happens on your phone.

None of the audio NightSnore captures ever leaves your device. No microphone data is uploaded, no recordings are sent to a server, and no account is required. The entire pipeline — adaptive noise tracking, AI sound classification, event recording — runs locally using Apple's on-device frameworks. Even the neural network inference happens right on your iPhone. You can delete everything from Settings at any time.

NightSnore

Try it tonight.

Place your iPhone on the nightstand, tap Start, and fall asleep.
Wake up to a clear picture of your night.

Download on the App Store

iOS 17.6 and later · One-time purchase · Not a medical device

References
  1. Aarts, R.M. et al., "Snoring: sources and correlates." Acta Acustica (2010). Available at: sps.tue.nl (PDF)
  2. González-Martínez et al., "Improving snore detection under different sleep conditions through harmonic/percussive source separation." Applied Acoustics (2024). doi:10.1016/j.apacoust.2023.109811
  3. MDPI Engineering Proceedings: "Cascaded false-positive rejection for snore event detection." doi:10.3390/engproc2022011008
  4. Xie et al., "Audio-based snore detection using deep neural networks." Computer Methods and Programs in Biomedicine (2020). doi:10.1016/j.cmpb.2020.105917
  5. Hong et al., "Real-Time Snoring Detection Using Deep Learning: A Home-Based Smartphone Approach." Nature and Science of Sleep (2025). doi:10.2147/NSS.S514631
  6. Brown et al., "Accuracy of Smartphone-Mediated Snore Detection." JMIR mHealth and uHealth (2025). doi:10.2196/67861