Tools · Noise planner
Enter the fan-noise reading and drag the listening distance — the calculator works out how many decibels remain where you stand, what it sounds like, and when it sinks below the night-time background.
Synthesized preview — headphones recommended. The volume follows the decay as you drag.
Still 5 dB above a quiet campground's ~40 dB background — clearly audible.
Units & measurements
Two abbreviations carry the whole page, and one table holds the measured truth behind it: fan noise for every P Series station, gear by gear, at 20 cm and 1 m.
A logarithmic yardstick for sound. +10 dB means ten times the sound energy but only about twice the perceived loudness; every −10 dB feels roughly half as loud. 0 dB is not silence — it is the edge of healthy hearing. For anchors: a quiet library sits near 40 dB, conversation near 60 dB, a vacuum cleaner around 70 dB.
Feet — the unit half of the audience thinks in. One meter is 3.28 feet, so the slider reads 2 m ≈ 7 ft and 10 m ≈ 33 ft. Both units describe exactly the same distance; use whichever you can pace out.
Questions it answers
Each card tells you which numbers to enter and which result to read. Find your question and follow the steps in the calculator above — your own distances, your own answer.
Enter 33.3 dB — the P600 at gear 1, measured at 1 m. It sits below the ~40 dB campground background before you drag anywhere, so the verdict card reads inaudible from the start. That is why it can run a CPAP through the night without waking anyone in the tent.
Take the loudest gear-3 reading in the table — 45.8 dB at 1 m (P2400) — and drag the slider: the level sinks below the ~40 dB background right around 2 m. The P1200 at gear 3 starts at 45.4 dB and fades just as fast; the P600 tops out at 38.6 dB and never crosses the line at all.
The gears are fan speeds, driven by cooling demand: gear 1 idles through light loads, gear 3 kicks in for fast charging or sustained high output. The spread shows in the table — the P1200 swings from 35.6 dB to 45.4 dB at 1 m between gear 1 and gear 3, and even that top gear stays below conversation level at the same distance.
Compare the 1 m columns with the background: every gear-1 reading (33.3–46.4 dB) sits at or below a quiet room, and even gear 3 never reaches conversation level at 1 m. Indoors, a wall or tent fabric takes a few more dB off the top — the calculator models open air, so real life runs quieter than the verdict card says.
How it works
It takes one measured number — fan noise at a known distance — and tells you what is left where you actually stand. There is no engine in these machines; the only thing that can make sound is a cooling fan, which is why the numbers start low and disappear fast.
A free-field sound model. Sound spreading from a point source covers four times the area with each doubling of distance, which costs 6 dB every time. The calculator subtracts that decay from your fan-noise reading and reports what remains at any distance from 1 to 50 meters — with an everyday sound to anchor the number and a verdict against the ~40 dB background of a quiet campground at night.
Questions & answers
Two honest distances: 20 cm is what your ears get with the station on the ground beside you, 1 m is a typical bedside or tent-side placement. Note the measured drop between the two columns is smaller than the ~14 dB an ideal point source loses over five times the distance — at 20 cm the case itself is not a point, and near-field sound decays more gently. The table holds what was measured; the calculator models what happens farther out.
They are fan speeds, chosen automatically by cooling demand. Gear 1 covers light loads and barely registers; gear 3 engages for fast charging or sustained high output. Same machine, same spot — the P1200 climbs from 35.6 dB at gear 1 to 45.4 dB at gear 3 (1 m), a gap of nearly 10 dB.
Practically none. There is no engine, no exhaust and no fuel pump — with no cooling demand the fans simply stop, and the machine contributes nothing you can hear. Standby draw is measured in watts, not decibels, which is why a station can sleep in the room where you sleep.
Not the same class of machine. Gas generators are conventionally rated around 68 dB at 7 m — louder at that distance than the loudest cell in our table at thirty times less space. A battery station has no combustion to muffle: the loudest measured reading here is 53.7 dB at 20 cm under full gear-3 cooling, and the whole lineup sits in the 30s and 40s at 1 m. That gap is what makes night-time and indoor use possible at all.
The table is measured in open air at chest height. Hard ground or walls reflect sound back, a corner or headboard focuses it, a blanket over the intake makes the fans work harder, and a full-speed charge pushes the top gear for longer. Placement and load explain most differences — give it airflow and open space and it settles back toward the table.
Use the calculator with the ~40 dB campground background: the loudest gear-3 reading (45.8 dB at 1 m) sinks below it right around 2 m, and the P600 at gear 3 (38.6 dB at 1 m) never crosses the line at any distance. At 1 m arm's length you are already at or below 46 dB on every model — close enough to keep the cables short and the night quiet.
