Horn test results. Should I buy louder ones?

[nwguy]

Before I buy new/louder horns for my 1999 Bassa I wanted to know if I add a relay with wires direct to the battery terminals to the stock horns, will the better connections make them significantly louder? Loud enough? Do I really need to buy new horns?

So I tested the horns using a free dB metering phone app from 10" and 14' away, first using the stock setup and then using wires direct to the battery terminals. For grins I also tested reversing the polarity to the horn terminals. My Bassa's left horn is the high tone horn. Low is on the right.

Battery
It was on a charger during this test since the horns draw a surprising amount of current. I didn't want test results to vary depending on battery voltage. Voltage readings were above 13 volts. I figure your battery will probably be charging most times you use your horn while riding.

Polarity
Original polarity was hot wires to inside connectors. Reverse polarity readings showed less than one decibel difference in loudness, so caring about this seems a wash unless there's some phase advantage that would require more testing.

Relay
To simulate using a relay without having installed one yet, I just used stout test cables with alligator clip ends to go from the battery terminals to horn terminals. I read this somewhere:
"Maximum allowable voltage drop for any relay or switch contact is 300mV (.300V)."
So the Direct db values may be a bit smaller in real world use.

I didn't have the stuff to make jumper cables to test the direct wiring with both horns on simultaneously. But based on the individual results, looks like combined they'd be significantly louder.

All readings are measured in decibels.

TESTS INSIDE GARAGE
       from 10" away   |  from 14' away
-------------------------------------------------------
       Stock  | Direct | dB chg | Stock  | Direct | dB chg
Both:  114.8  |        |        | 99.8   |        |
Left:  116.9  | 117.2  | +0.3   | 102.6  | 117.1  | +14.5
Right: 108.4  | 115.1  | +6.7   | 87.0   | 108.4  | +21.4

Initially I did these tests in my garage with the doors closed. It's echo-y in there. I should have done all these test outdoors. So I did more tests to tell how fewer decibels there were outside than in the garage. No difference in 10" away, but 14' away:

OUTDOOR TESTS with stock wiring from 14' away
       In garage | Outdoors | dB change from in garage
-------------------------------------------------------
Both:  99.8      | 92.7     | -7.1
Left:  102.6     | 92.4     | -10.2
Right: 87.0      | 82.1     | -4.9

End result, my horns make 92.7 dB in real life situations. I haven't found how advertised horn volumes are tested. Seems to me, outdoors from maybe a 30-50 foot distance would make the most sense. I suspect modern, louder horns rated at 120+ dB are much louder than mine.

Next up, same test on my stock headlight with a light meter app.

[bronzestar1]

If you're going to go thru the trouble of wiring up a relay to your stock horns, you might as well go with new horns, like Fiamm Freeway Blasters, or even better, a compact air horn like a WoLo Badboy.  Either one of those will definitely be louder than most OEM motorcycle horns. 

[moto]

...
End result, my horns make 92.7 dB in real life situations. I haven't found how advertised horn volumes are tested. Seems to me, outdoors from maybe a 30-50 foot distance would make the most sense. I suspect modern, louder horns rated at 120+ dB are much louder than mine.

I believe one meter is the usual test distance. I found distances by carefully examining manufacturers' websites.  If you take your readings at one meter you should get markedly different results, maybe up near the claimed values of manufacturers.
 
Your right horn gives surprisingly low values compared to your left one. Are you testing it at a different angle? Maybe try putting it in exactly the same spot when you make your tests.

I am not surprised that direct wiring doesn't increase the decibel level much. Some people advocate using a relay to reduce the voltage at the OEM switch to keep it from early failure. I don't know how well that works.

I think your tests are a good idea. Make sure you can get very similar values in repeated tests before taking results as definitive. Good luck.

P.S. I find flashing very bright lights more effective than honking very loud horns at longer distances. I have both, in spades.

[Dr. Enzo Toma]

If those are the original horns, the difference in volume left to right may simply be due to how the horns have weathered and aged. They are basically speakers with a diaphragm that is exposed to the elements, with wind being a rough one.

[normzone]

If memory serves me well, which it may not, the Hella Horns I replaced my stock '99 Bassa horns with tested out at 114 db.

[JoeB]

98EV here and have run stock, freeway blasters, and lately a set of Hellas.
The blasters in my opinion were head and shoulders ahead.
Didn't do any testing on them other than observations from practical use.
FWIW wiring on my era of bike already had the horns coming off a relay.
Not sure of others. Also Merry Christmas!
https://dpguzzi.com/cal1100i_x.pdf

[JJ]

I can FART louder than most "stock" motorcycle horns...

I had one of these STEBEL Nautilus Air Cannon horns on my old 2014 Victory Vision Tour.

It was a "blaster" and as loud like a train horn.   Highly recommended...

[jbhotchkiss]

Lots of good, reasonably-priced LOUD horns out there. Given the prevalence of distracted idiot drivers on the roads these days, I recommend new horns. WOLO, Farbin, Stebel, etc.

[StuCorpe]

I went the route of adding an airhorn and throwing the original horns away.  The airhorn is much louder to my ears but have never made any measurements on it.

[JJ]

I went the route of adding an airhorn and throwing the original horns away.  The airhorn is much louder to my ears but have never made any measurements on it.

Usually, they are all about 139dB+

I once blasted a distracted driver in a large white Cadillac SUV who cut me off, and it was so loud, he fumbled and dropped his cell phone to the floor!!

[nwguy]

The wiring diagram for a 2000 Jackal that seems to apply to my Bassa shows my horn using a relay. I replaced all my relays with new ones from Dan Prunuske during my restoration. Despite this relay, I'm seeing from different installation instructions for compressor-driven horns that I'd need to use the new horn's supplied relay with heavier gauge wires. And then use one of the positive wires to my stock horns as the signal wire for the relay. Correct?

The Stebel Air Cannon's packaging shows dB levels measured from 4 inches and 6 feet away.

The Fiamm Freeway Blasters come in low and high, so I suppose I would buy one of each. Would these be a direct replacement? Or would they require a 30 amp relay and heavier gauge wires?

[guzzisteve]

Those are real loud and it's fine on way you're doing install.

2 of the Guzzi's I ride don't have a horn, just deleted at sometime in past, stuff stops working & you pitch it. Last was air horns on the sidecar rig.

[nwguy]

I've read at least one opinion saying if you need to use your horn, it's too late. I disagree. Too many times I've seen people about to turn left in front of me that I've thwarted by using horn, lights, finger, or whatever it takes. Plus, a horn may be used to prevent an accident but it can also be used to tell a driver that they made a mistake and should be aware of it. Though these days that might result in a road rage thing.

[guzzisteve]

They have Fiam's at the auto parts store and reasonable. That is what it came with new.

[MG_rider]

If you want a louder horn go with the Stebel or Nautalis as recc'd by JJ.

You should use a relay because the inductive kick-back when you let go the button is 10X the running load current.  That can burn out the contacts on the horn button.