Hella Marine B36 Low-Tone Disc Horn 24V | 116 dB

The Hella Marine B36 is a low-tone disc horn built to be heard. It puts out 116 decibels at a deep 335 Hz, and that low pitch carries. On a busy waterway or a crowded work site, a low tone cuts through engine noise and wind better than a thin high note does. This is the horn you reach for when you want people to actually notice you.

116 decibels is genuinely loud. That's about the level of a live band measured up close, so this is not a polite little beep. It's a warning signal meant to get attention across distance and over the racket of engines, generators, and traffic. If your current horn sounds like a sick goose, stepping up to a 116 dB low-tone unit is a night-and-day upgrade.

First thing to know: this is a 24 volt horn. It's wired for 24V electrical systems, the kind you'll find on larger boats, commercial rigs, and heavier equipment. If your boat runs a 12 volt system, this isn't the horn for you. Check your system voltage before you order. Feed a 24V horn 12 volts and it'll sound weak and flat, if it sounds at all.

The design is a classic disc horn. Compact, round, 4.40 inches across, with the whole works packed behind a silver and black diaphragm. Disc horns like this one mount almost anywhere you've got a few inches of clearance, which is why they've been a go-to for decades. The housing is galvanized metal, so it shrugs off the kind of surface corrosion that eats cheaper horns alive. Mounting brackets come in the box, so you're not hunting for hardware on install day.

Let's talk wiring, because this is where a lot of horn installs go sideways. At 72 watts on a 24 volt system, this horn pulls roughly 3 amps. That's more than you want running through a dash button or a flimsy switch. Wire it through a relay. Run the heavy leg from the battery through an inline fuse to the relay, then out to the horn, and use the horn button only to trigger the relay coil. Ground the horn to clean, bare metal. Do it that way and the horn sounds full every time and your switch lasts for years. Skip the relay and you'll be chasing a weak honk and a hot switch down the road.

Where you put it matters too. Point the horn opening slightly downward so water drains out instead of pooling on the diaphragm. Galvanized housing or not, no horn likes sitting in standing water. Tuck it behind a panel or under a console where it's protected from direct spray but still has a clear path for the sound to escape. A horn buried in a sealed box gets muffled fast.

This is the low-tone half of the B36 family. On its own it's a strong, deep single note that does the job. If you want that classic two-tone sound, the kind that really turns heads, pair it with the matching high-tone B36 horn and wire both to the same button. Two horns, two pitches, one push. That's a setup a lot of folks run on bigger boats and rigs where they want to be unmistakable.

Bottom line: the Hella B36 low-tone disc horn is a simple, durable piece of gear that does one thing well. It's loud, it's built to last, and it installs clean if you wire it right. For any 24 volt rig that needs a serious horn, it's an easy call. And if you're not sure whether your system is 12 or 24 volt, give us a shout before you order. We'll help you get the right part the first time.