ENVO: Adaptive Volume

Your volume, minus the noise.

You know the dance. On the train, a tunnel roars and you can't hear your podcast, so you turn it up. The train stops and now it's blasting, so you turn it down. Café, gym, plane, sidewalk: all day, your thumb does a job a machine should be doing.
ENVO is that machine. It listens to the room and gently levels your volume to match, up when the world gets loud, back down when it quiets, so what you're hearing stays in the same comfortable place. You set the volume. ENVO keeps it right.

HOW IT WORKS
Ten times a second, ENVO measures your surroundings through the microphone — not just how loud the room is, but how much of it is actually burying what you're listening to. Then it eases your volume up or down by a small, safe amount. Your chosen level is always the baseline: the instant you touch the volume buttons, that becomes the new normal. You are never fighting the app.

BUILT ON REAL PSYCHOACOUSTICS
• Measures masking, not just loudness. A bus or a plane cabin is mostly deep rumble a sound meter barely registers — yet it's what makes speech impossible to follow. ENVO splits the room into frequency bands and weighs each by how much it's burying your audio.
• Thinks in decibels, the way your ears perceive loudness — an adjustment feels the same whether you started quiet or loud.
• Defends against the Lombard Effect — why a restaurant slowly gets deafening as people raise their voices. ENVO tells voices from machinery by their frequency and by the rhythm of speech, then refuses to chase people simply talking louder.
• Rejects transients — a door slam is loud but brief, and ENVO shrugs it off.
• Knows its own voice. On a speaker the mic hears your music too — ENVO measures how much of what it hears is its own doing and takes that back out, so it can't chase itself upward.

ROOM CALIBRATION
Every iPhone's volume slider is a curve, not a straight line. A 35-second calibration measures yours, so the range you choose is the range you get. Until then ENVO plays it safe and adjusts a little less than asked.

SAFETY FIRST
ENVO is engineered so it can't run away with your ears:
• A hard ceiling it will never exceed.
• A range cap (±3, ±6, or ±9 dB) you choose.
• A hard limit on how far it can move the slider.
• Gradual, rate-limited changes — ENVO must see several seconds of consistent change before it moves at all.
• Your manual volume change always wins, instantly.

HONEST WHEN IT CAN'T HELP
ENVO says plainly when it can't do its job, instead of reporting numbers it can't stand behind:
• Microphone covered — pocket, bag, or face-down. ENVO can tell a muffled mic from a room that just went quiet, and holds steady rather than act on a reading it doesn't trust.
• Nothing playing — it hands the volume back, so your next track never starts at a level you didn't choose.
• An output that keeps its own volume, like an AirPlay receiver. ENVO says so instead of pretending.

WHERE IT WORKS
Commutes, cafés, open-plan offices, flights, the gym, a bar filling up. ENVO runs in the background with any audio app (Music, Spotify, Podcasts, YouTube, audiobooks, calls...) keeps hi-fi stereo on your Bluetooth headphones, and leaves your lock screen to your music app. Start and stop with Siri, the Action Button or Shortcuts.

Headphones are its best case: the mic hears the room, not your music. Speech works out loud too, because the gaps between sentences let it hear underneath. With continuous music out loud, ENVO turns up for a noisier room and returns you to your chosen level — but can't go below it, because your music is then all the mic can hear. A limit of every microphone, not a shortcut.

PRIVATE BY DESIGN
No audio is ever recorded, stored, or transmitted. Only instantaneous sound levels are measured in memory and discarded. Everything runs on your device. No account, no server, no analytics. Free and OpenSource.

ENVO reads your environment so your ears don't have to.

From TOTEMPHONIA STUDIO BERLIN