Hopefully not on the day you need it.
I built what used to be the best-selling personal alarm brand in the country (Vigilant), sold it to Mace, and spent years inside that category as an executive. Then I walked away.
I came back because the thing that fails in a personal alarm is almost never the thing buyers are told to shop for.
Every alarm on the shelf leads with the same number: 130 dB. No regulatory authority checks it. No agency tests personal alarm output. No standard defines how it gets measured, at what distance, on what cell, at what point in that cell's life. Truth-in-advertising enforcement has never gotten into the weeds of how much audible power sits inside a keychain siren. So 130 dB stopped being a specification a long time ago and became a convention.
I bought competitive products decibel meter tested their alarms myself. Most of it isn't close. The units I've tested average 110 to 120 dB at source. Some products printing 130 dB on the front measured under 100 decibels.
Resonant™ produces a true sustained 133 dB at source, and holds full volume and full power for the entire 50-minute runtime.
Written down, those gaps look small. Decibels are logarithmic. Every 10 dB is roughly a doubling of how loud something sounds to a human ear, so an alarm running 20 dB behind is a quarter as loud and carries about a tenth as far. That's an alarm heard across a football field versus an alarm heard across a park bench.
Nobody is carrying a decibel meter. Not the customer standing in the store, and not assailant.
So don't take my word for it. Here's the Resonant™ actual decibel meter test.
That's the standard I'm willing to be held to. (By the way, this video was recorded for me at the factory as I required a decibel test of production models.)
In a business with no regulatory controls and no penalty for printing a number you can't produce, the only accountability available is showing the actual reading, and we're perhaps the only company that will do so.
Because the (overstated) number on a package is a day-one number. Nobody sells you the day-400 number, and the day-400 number is the only one that has ever mattered. What will this alarm do after 400 days of standby in your purse?
The failure mode nobody tests
You buy an alarm, clip it to a bag, and carry it for years hoping you never touch it. It sits in standby the whole time, and the whole time the battery is draining.
The button cells that power most personal alarms don't fail cleanly. They fade.
An LR44 button battery has very little capacity to start with. That's the reason I used to use three of them to build an alarm.
As the cell depletes its voltage sags under load, and a small piezo siren (speaker) is a load. So the alarm doesn't stop working. It gets quieter. Then quieter. Then it's a chirp.
You will never notice. There is no low-battery warning on a device you never turn on. You test it in the store, hear something loud, and file it away as working. It keeps telling you it works right up until the moment it needs to be loud and isn't.
Nearly every other personal alarm on the market will get quiet before it stops working altogether. That's why we built Resonant. Resonant's tag line is
Why I went to AAA
The industry defaulted to button cells for one reason: thinness. Slim sells on a peg hook.
I understand the tradeoff. I made it myself, years ago, in a category I helped define. I've had a long time to think about whether it was right.
It wasn't. Resonant runs on a standard AAA alkaline in a half-inch housing, so nobody has to choose between a slim device and a device that still works in year three.
Capacity. 1 AAA alkaline holds roughly eight times the energy of a typical alkaline button cell. That's chemistry and volume, not marketing.
Sustained output. More capacity and better voltage stability under load means the siren holds 133 dB instead of tapering toward it. Peak performance on day one is easy. Day 400 is the engineering problem we solved.
Runtime. Fifty minutes of continuous alarm at full 133 dB. If you have ever needed help, the difference between twenty minutes and fifty is not academic.
Replacement you'll actually do. AAA batteries are in every gas station and pharmacy on earth. An LR44 three-pack is a special trip, and people don't make special trips for a device they hope never to use. They let it die.
Shelf life. Quality AAA alkalines hold their charge up to a decade in storage. Most button cells are rated three to five years.
Safety. Button cells are a well-documented ingestion hazard for small children. A device marketed to families should not carry three of them.
Nerd science: why button cells leak first
Skip this if you don't care. I care, so here it is.
Alkaline cells all leak by the same mechanism. Drive a cell into deep discharge and gas pressure builds inside it, the seal vents or fails, and potassium hydroxide escapes and reacts with carbon dioxide in the air. That's the white crust on the contacts of an old remote.
Nothing about button cell chemistry is more corrosive than a AAA. Three things make it happen sooner.
It reaches deep discharge years earlier. Leaking is a deep-discharge event. A 150 mAh cell sitting in standby gets there in a fraction of the time a 1,100 mAh cell does, and then it starts eating the contacts it sits on.
Three cells in series compound it. When cells in series discharge unevenly, the stronger ones drive the weakest into voltage reversal, which sharply accelerates gas generation. Three small cells drift apart faster than two larger ones.
The seal has less to work with. AAA has a crimped seal with a dedicated pressure-relief vent, engineered to fail in a controlled way. A button cell is a gasket pinched between a can and a cap.
AAA alkalines leak too, it just takes longer. Anyone who has opened a drawer of old electronics knows it. The claim isn't that one format is immune. It's that a personal alarm is close to the worst possible application for a button cell that reaches deep discharge quickly, because it's the one device you never open and never check until the day it matters.
Corrosion doesn't announce itself either. Same problem as fade, one layer down.
What I learned building the last company
The lesson wasn't about volume or distribution or the exit. It was that in personal safety, the customer can't evaluate the product. They can evaluate the packaging, the price, and the number printed on the front. The only real evaluation happens once, under duress, at the worst possible moment, and by then it's too late to buy something else.
That asymmetry is a responsibility. Most of this category treats it as an opportunity.
Resonant is built around the decisions a buyer can't see on a peg hook and will never have to think about. No feature that exists to win a spec sheet comparison.
Attention changes everything. That's the premise of a personal alarm. You aren't fighting, you're refusing to be invisible. Every design decision either serves that or it doesn't.
The first fix I made was the battery, and that makes all the difference.
Resonant™ Personal Alarms. You Will Be Heard.
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