I want really loud car horns

[masraum]

But the miata doesn't have tons of space. It's got the most horrible, pathetic horn ever.

I want LOUD. The problem is that some horns list the dB, but they don't list how far from the horn that sound was measured. Some list a high value like 130dB, but it's at 4". Well, it's unlikely that waiting until I'm 4" from the car in front of me is going to do much regardless of the horn I use. Some list 112 or 118dB at 4 feet or 6 feet. That may be good, but I'm not certain exactly how to do the math to determine which is better 130dB at 4" or 112 at 4 feet. I'm pretty sure the deal is the inverse square, but I'm not 100% certain that I've got the math right. Just thinking out loud, 130dB at 4", at 1 meter which is almost 40" I'd be 10x farther away, so the sound pressure should be 1/100th. But the dB scale is logarithmic, so at 40" the db shoud be 128dB? So at 6 feet, it would be 72" which is 18x farther away so 1/324 as loud, so 324 is approx 10^2.5 so at 6 feet it'd be about half as loud because it's almost 3dB less than at 4".

That makes it sound like the nautilus should be pretty darn loud. Certainly louder than the 118 Hella supertone kit.

And, the nautilus is about half the price of the hella kit which runs about $65.

But, I'm not certain about my math. Can anyone confirm or deny?

[red-beard]

A 10 dB change is a power of 10. If inverse square holds, a 1/100 change in dB would be a -20 dB change. So, 130 becomes 110. Comparing 110 to 118, is an 8 dB difference, which is a little less than 8 times the power (9 dB = factor of 8).

[on2wheels52]

On my bikes I usually unplug or remove the horns. I don't want fumbling for the horn button to come up on my drop-down list of options when large objects are invading my lane.
If there's people who can't hear sirens they sure won't hear a horn that sounds like someone strangling a duck.
Jim

[id10t]

Friend who drove a MG for years had a semi air-horn installed under the hood...

[lendaddy]

If I remember correctly, you'll gain 3dB by doubling the power to the horn (assuming it can make use of it) and gain 6dB by doubling the horns. Go to the wrecking yard and get 1-3 more.

[VINMAN]

Stop in you local boating supply store. Pick up a nice set of marine horns!

[TerryBPP]

Its popular in Miami to use a actual train horn on your SUV. About 5 years ago we mounted one on a guys Surburban. 0.5 ho compressor under the rear bumper and a 2 gal air tank. It was deafining. Completely ridiculous but fun to build.

[legion]

Griott's sells a compact air horn for around $40. Don't know how well it works.

When I bought my 951, the horn did not work. I replaced them both (high-tone and low-tone) and now it works. It was a priority as people in minivans talking on their cell phone seem to like to switch lanes into the space my car is occupying.

[mschuep]

A few rules of thumb...

If you double the power you gain 3 dB, which would be the same as adding an additional horn. Every time you double the distance you lose 6dB. An increase of 10 dB is percieved as something twice as loud. Likewise, a loss of 10dB sounds about 1/2 as loud.

Some ratings may be listed as sound power level, instead of sound pressure level at a distance...You can't do an apples to apples comparison without first changing the sound power level to sound pressure level.

JCWhitney has a large selection of horns.

[masraum]

Originally posted by red-beard
A 10 dB change is a power of 10. If inverse square holds, a 1/100 change in dB would be a -20 dB change. So, 130 becomes 110. Comparing 110 to 118, is an 8 dB difference, which is a little less than 8 times the power (9 dB = factor of 8).

Thanks, that should fix my incorrect math.

[rammstein]

Originally posted by TerryBPP
Its popular in Miami to use a actual train horn on your SUV. About 5 years ago we mounted one on a guys Surburban. 0.5 ho compressor under the rear bumper and a 2 gal air tank. It was deafining. Completely ridiculous but fun to build.

Yeah, you're right. I have heard these things- it scares the crap out me.

[masraum]

I've seen some videos on the net of guys driving around and honking as he drives past unsuspecting bystanders.

I don't need anything quite that loud. Just the loudest regular car horn that will easily fit in the miata.

[VINMAN]

I prefer a nice indescreet horn setup like this one..

[xlr8]

Chrysler hemi-138 dB @100'

[masraum]

I want to fit the horn in the miata, not the other way around.

[dbrisson]

go to http://www.hornblasters.com/
funny videos, parts and how - tos everything you need.

The videos are great....

[Rick V]

For a sensable alternative, get a set of BMW E30 horns. They have that 1965 Buick volume, and they are smallish. Boneyard pickup for cheep.

[WolfeMacleod]

I had an old AOOOGAH horn once. It was pretty loud.
Kinda wanted to find another one and load it into my 924S...

[trekkor]

I had a VW Rabbit with 4 horns under the hood.
3 mid 1960's Mopar and one trumpet. All 12v electric.

I kid you not, it sounded *just* like Amtrak. Ridiculously loud.


KT

[masraum]

Originally posted by WolfeMacleod
I had an old AOOOGAH horn once. It was pretty loud.
Kinda wanted to find another one and load it into my 924S...

http://www.jcwhitney.com/autoparts/Product/Pr-p_Product.CATENTRY_ID:2009071/c-10101/Nty-1/p-2009071/Ntx-mode+matchallpartial/N-10101/tf-Browse/s-10101/Ntk-AllTextSearchGroup?Ntt=horn

second horn down
http://www.wolo-mfg.com/spec.htm