Quell
Quell

Intelligent sound masking.
Take control of your environment.

The adaptive acoustic-privacy device that turns any surface — even a window — into an invisible source of calm.

Firmware · App · Cloud Engineered in Linz, Austria Investor Briefing · 2026
QUELL — CONFIDENTIAL
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The feeling we all know

On a beach, the sea protects you.

The wash of the waves blurs the voices around you — so you relax.

…and when it stops

Now imagine the sea falls silent.

Suddenly every word is crisp. Nothing changed — yet it disturbs.

The absence of the right sound is what breaks the calm.

The modern workplace

Modern offices went quiet.

  • Silent keyboards, silent printers, phones that never ring.
  • The background noise that once covered speech is gone.
  • So every word at the next desk is crystal clear.
The science of intelligibility

We pause about 4 times a second when we speak.

Intelligibility hides in those tiny gaps — and in the consonants. The quieter the room, the more you catch.

~4 micro-pauses / second

Fill those gaps with the right sound, and speech loses its edge.

THE PROBLEM
Wherever people talk, privacy leaks

The same problem — in every serious room.

🏢

Office

Overheard strategy talk.

🩺

Medical

Patient confidentiality.

🏦

Banking

Account details in the queue.

⚖️

Legal

Client privilege.

Privacy is now a compliance requirement — GDPR and professional secrecy turn overheard speech into real liability.

THE PROBLEM
Two costs, every day

Lost focus

Intelligible speech is the #1 open-plan complaint — it fragments deep work.

Confidentiality risk

In regulated settings, one overheard conversation can mean a breach.

The solution

Meet Quell.

A small, elegant device. Set it down — and it turns an ordinary surface into an invisible source of calm.

No visible speakerNo wiring
Quell device — a soft white puck with two touch buttons
THE PRODUCT
How it disappears

A surface exciter, not a speaker.

It couples to a desk, panel or glass pane and makes the surface itself radiate a gentle masking sound.

  • Invisible — the surface is the speaker.
  • Even, diffuse coverage; no obvious source.
  • Nothing to mount, nothing to wire.
Quell device coupling to a surface
THE PRODUCT
The masking principle

It dissolves the consonants.

  • Fills the micro-pauses with pleasant sound.
  • Covers the consonants where meaning lives.
  • Words dissolve before they reach you — unintelligible, not louder.
The real differentiator

Adaptive by design — a closed control loop, not a loop player.

🎙 Mic
Samples the room ~31×/sec
→
AEC
Removes its own sound
→
RMS
Measures ambient level
→
PID
Adjusts volume smoothly

Volume rises when the room gets lively and eases back when it calms — automatically, on-device, no cloud required.

THE PRODUCT
Your soundscapes

Choose the calm that fits the room.

🌊

Warm masker

The signature blend.

⚪

White · Pink · Brown

Classic noise.

🌧

Rain · Sea · Forest

Natural ambiences.

⬆️

Your own audio

Upload .wav / .mp3.

An 8-band equalizer tunes it to the room. New soundscapes arrive over the air.

THE PRODUCT
Control in your pocket

The whole system, one tap away.

Find your devices over Bluetooth, secure each with a PIN, and control everything.

iOS & AndroidEN · DE · FR · ES
Quell app device list
THE PRODUCT · REAL SCREENS
Control in your pocket

Volume, soundscapes, EQ — live.

  • Precise volume with presets & fine steps.
  • Switch soundscapes; tune the 8-band EQ.
  • Toggle adaptive mode; update firmware over BLE.
Quell app device detail
THE PRODUCT · REAL SCREENS
No phone needed

Two touch buttons on the device.

  • Tap to mute; hold to toggle adaptive mode.
  • Second button adjusts volume.
  • Hold both to reset — settings persist across reboots.
Quell device with two black capacitive touch buttons on top

Two capacitive touch points on the top surface.

THE PRODUCT
Under the hood

Three engineered layers.
One seamless product.

Firmware, app and cloud — each built in depth, verified on real hardware.

System architecture
📟 Firmware
ESP32-S3 · C
  • Adaptive DSP (AEC · PID)
  • Soundscapes · 8-band EQ
  • BLE · WiFi · Mesh
  • Signed OTA
📱 Mobile app
Expo · React Native
  • BLE control & setup
  • PIN · 4 languages
  • OTA over Bluetooth
  • Demo mode
☁️ Cloud
.NET 8 · Blazor
  • Multi-tenant fleet
  • Real-time mesh view
  • OTA & audio delivery
  • Live control
📶 BLE — phone ⇄ device🔒 HTTPS — device ⇄ cloud🕸 ESP-NOW — device ⇄ device
THE SYSTEM
Layer 1 — Firmware

Real-time DSP on a low-cost SoC.

  • ESP32-S3 · 16 MB flash · 8 MB PSRAM · ESP-IDF/C.
  • I2S amp + MEMS mic driving a resonance exciter.
  • Closed-loop masking, WAV/MP3, 8-band EQ.
  • BLE + WiFi + ESP-NOW mesh, tuned to coexist.
Quell PCB schematic

Actual hardware schematic — ESP32-S3 · I2S amp · MEMS mic.

THE SYSTEM · FIRMWARE
Layer 2 — The app

Store-ready, on a modern stack.

  • Expo 54 · React Native · React 19 · TypeScript.
  • ~30-characteristic custom BLE-GATT protocol.
  • Guided setup wizard · demo mode.
  • EAS build & submit — iOS & Android.
THE SYSTEM · APP
One wizard, three modes

Scales from one desk to a whole floor.

  • Standalone — a single device.
  • Mesh — many devices, coordinated.
  • Privacy-Glass — a window becomes a barrier.

All chosen in the same guided wizard.

Quell grouped devices: mesh, privacy-glass, standalone
THE SYSTEM · APP
Layer 3 — The cloud

Manage 1 or 100 devices.

  • .NET 8 API + Blazor WASM PWA, multi-tenant.
  • "The Grid" — real-time mesh & telemetry.
  • Fleet OTA + audio; live control.
  • Web-Bluetooth provisioning in the browser.
☁ Quell Cloud · The Grid
12 online
Office-A · Root
42dB
Office-B · Leaf
55dB
Lobby-C · Leaf
39dB
Meet-D · Leaf
44dB
Window-E · PG
◧ mask
Desk-F · Solo
41dB

Representative admin UI, styled to the product theme.

THE SYSTEM · CLOUD
Over-the-air, end to end

Ship firmware & sound to one device — or a whole mesh.

⬆ Upload
Build uploaded; SHA-256 recorded
→
🚀 Deploy
Signed command + checksum
→
⬇ Pull
Device downloads (resumable)
→
✓ Verify
Progress reported live
Firmware & audio One device or mesh-wide SHA-256 · anti-downgrade · auto-rollback
THE SYSTEM · OTA
The moat

Why this is hard
to copy.

Four layers of defensibility — from a rare acoustic feature to full-stack security.

Moat #1 — the mesh

A self-healing acoustic network.

  • ESP-NOW mesh, up to 20 devices, Root/Leaf.
  • Root bridges to cloud; Leaves work offline.
  • HMAC-authenticated; firmware travels the mesh.
  • One phone, one setup — the floor stays in sync.
☁ Cloud Root Leaf Leaf Leaf Leaf
THE MOAT
Moat #2 — the killer feature

Privacy-Glass turns a window into a barrier.

  • On-device 4096-point FFT reads the glass's resonances.
  • It masks exactly those frequencies through the pane.
  • Defeats laser & contact-microphone eavesdropping.

Acoustic counter-surveillance — in a device this size.

Moat #3 — security by design

Every layer, hardened.

BLE linkECDH P-256 + AES-GCM + PIN lockout
Firmware OTARSA-2048 signed · anti-downgrade · rollback
Cloud APIJWT + BCrypt + per-device tokens
WiFi credsAES-encrypted, bound to chip ID
MeshHMAC-SHA256 authenticated frames
Commandsstrict allow-list + validation

Honest next step: hardware Secure Boot & Flash Encryption fuses — in software today, locked in production.

THE MOAT
Moat #4 — built like it matters

Rigor you can measure.

254
commits over ~6 months of focused build
3 / 3
layers integrated (fw · app · cloud)
~3,600
automated tests & assertions
7
prototypes verified on real hardware

Unusual discipline for hardware at this stage — firmware DSP tested with a full mock layer; app verified with on-device E2E.

THE MOAT
The opportunity

A growing market,
with the wind behind it.

Market size

An established category — and accelerating.

$1.2B → $2.2B
smart sound-masking devices, 2025 → 2034
~7.8%
CAGR (smart sound-masking devices)
2-digit
CAGR reported for the broader systems market

Legacy masking means wired ceiling installs. Quell brings an adaptive, invisible, app-managed alternative.

Sources: industry market reports, 2025 — estimates vary by definition; shown as a range.

THE OPPORTUNITY
Why now

Four tailwinds converging.

🏢

Open-plan & hybrid

Quieter offices raise the value of privacy.

📜

Privacy regulation

GDPR makes overheard speech a liability.

🧠

Focus economy

Deep work is a board-level priority.

⚡

Edge DSP

Adaptive acoustics now fit a cheap device.

THE OPPORTUNITY
Where Quell sells

Five verticals, one product.

Office

Focus & privacy

Medical

Confidentiality

Banking

Financial privacy

Legal

Client privilege

Hospitality

Calm & brand

The same device, positioned for each buyer's core need.

THE OPPORTUNITY
Positioning

Traditional sound masking vs. Quell.

Legacy systems

Wired ceiling installs

  • Speakers wired above the ceiling
  • Costly professional install
  • Static — rarely adapts
  • Hard to move or scale
Quell

Invisible, adaptive, managed

  • Surface exciter — no wiring
  • Adaptive — regulates to the room
  • App & cloud managed, 1 → 100
  • Privacy-Glass — they can't match it
THE OPPORTUNITY
Business model

Hardware today, recurring tomorrow.

📦

Device sales

B2B hardware, priced per unit — scales with rooms.

☁️

Cloud / SaaS

Optional subscription for fleet OTA & monitoring.

🤝

Channel

Direct plus acoustic & workplace integrators.

Go-to-market plan; pricing to be finalized with early pilots.

THE OPPORTUNITY
Where we are

Not a concept.
A working system.

Traction & status

Real hardware, real software, real progress.

7
prototype devices on real hardware
iOS + Android
store submission underway
E2E ✓
OTA · mesh · WiFi · audio verified
3 layers
integrated & running

Built-in demo modes mean the full experience is presentable today — no hardware required.

STATUS
"Full phone OTA verified end-to-end."

Firmware over Bluetooth, on real boards. On-metal bugs found and fixed. Thousands of automated checks. This is engineering that has met the physical world.

STATUS
Full transparency

Done — and honestly, what's next.

✓ Working today

Shipped & verified

  • Adaptive DSP, soundscapes, EQ
  • Mesh, Privacy-Glass, full OTA
  • Store-ready app; .NET 8 cloud
  • End-to-end security in software
▶ Next steps

Production hardening

  • Hardware Secure Boot + Flash Encryption
  • Activate on-device voice control (built)
  • Production cloud & certification (CE/FCC)
  • Register own BLE company ID
STATUS
Roadmap

From validated prototype to market.

1 Now
  • Validated prototypes
  • App-store submission
  • Investor & pilot talks
2 Next
  • Production hardening & certification
  • Secure-boot lock-in
  • First paid pilots
3 Later
  • Scale fleet + cloud SaaS
  • Activate voice control
  • New verticals & regions
ROADMAP
The ask

Let's take Quell from prototype to product.

Partners & investment to cross from validated prototype to market. Where it goes:

🏭

Production

Manufacturing, secure-boot, CE/FCC.

🚀

Go-to-market

Vertical pilots, sales & channel.

☁️

Cloud

Production hosting & SaaS.

👥

Team

Extend a high-leverage core.

Let's take control of the environment — together.

THE ASK
Quell
Quell

Intelligent sound masking.
Take control of your environment.

Engineered in Linz, Austria.

Thank youLet's talk
grid = overview · play = auto-loop · S = notes