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Frequently Asked Questions
What exactly is an air horn?
An air horn is a horn powered by stored compressed air instead of a small electric direct drive air compressor. Air from a tank releases through an electric valve and rushes past a diaphragm inside the horn, and that vibration, amplified by the trumpet, is the honk. More stored air and a bigger trumpet mean a louder, deeper sound than any factory horn can make. Every product card on this page has an audio player, so you can honk through the whole lineup right here before you pick.
What is the difference between an air horn and a train horn?
The tone, not the trumpet count. A train horn's trumpets are tuned together to play the deep chord real locomotives use, while an air horn produces a sharper, higher-pitched blast. Trumpet count doesn't decide the category: our Rage 4-Chime runs four trumpets and is still an air horn, because it isn't tuned to the locomotive chord. Both run on the same kind of air system, so the choice comes down to the sound you want, not the plumbing.
Do these air horns come with an air system?
No, the horns on this page are stand-alone: the horn with its electric air valve, ready to plumb into air you already have. If your vehicle already has onboard air, connect the horn and honk. If it doesn't, you need the tank and compressor that feed it, and the easier path is a complete air horn kit, which pairs one of these horns with a matched air system in one box.
Which air horn has the highest decibel rating?
The Bullet, which measured 145.8 dB in third-party testing by DJD Labs, the loudest air horn we sell. For scale, most electric horns run around 120 dB, and the gap between those numbers is far bigger than it reads, since decibels are logarithmic. Ratings you see advertised above that range were measured at a non-standard distance or invented. Our decibel guide has the full side-by-side results.
What kind of air horn do semi trucks use?
Real semis run air horns straight off the truck's own air supply, which is why nothing else on the road sounds like one. The closest match here is the Mother Trucker, a 29-inch metal horn built to deliver that same deep big-rig tone on a pickup or SUV. Length is what makes the difference: the longer the horn, the deeper the note, and short compact horns simply can't reach that low.
Do air horns run on 12 volts or 24 volts?
It depends on the horn. The horn itself is air-powered, so the only electrical part is the valve, and valve ratings vary across this collection: some horns carry a valve rated for both 12 and 24 volts, but not all of them do. Check the specifications on the product page for the valve rating before ordering, especially for a commercial or military truck, and our 24-volt horns page collects everything built for 24-volt systems.
How much PSI does an air horn take?
Most of these horns run on systems between 90 and 150 PSI, and around 150 PSI is the sweet spot for peak volume on most horns. More is not louder: pushing past the sweet spot raises the pitch and thins the tone instead. What matters just as much is volume of stored air, since the horn honks off the air system behind it, and a starved tank cuts a honk short no matter the pressure.
Does weather or road spray hurt an air horn?
No. These horns are built to mount exposed, so weather and road spray aren't a problem, and they can bolt anywhere solid you can run air line to: behind the bumper, along a frame rail, in the bed, or under the body. Deeper-toned horns are long, so measure your straight run first, and horns with individually mounted trumpets can spread across the vehicle when one long horn won't fit. If you'd rather not do the install, our installer locator finds a shop near you.