u sure can get aftermarket horns.
u can get ur standard horn like most cars have, but u can get louder ones..
but if u want something loud. go air horns.
u can get from 1 to about 6 horns
if u are going to replace ur normal horn there east to install as the compreser hooks up to the wires that are already going to ur cars horns.. then u just gota mount the horns and plum some plumbing. easy and loud.
Real air horns don't have to be that expensive, if you're lucky and shop in the right places. I picked up some new-in-box Grover http://www.groverproducts.com air horns at swap meets cheap, plus one big used horn that's over 2 feet long. For a compressor I've got one that came out of some car application (maybe air shocks); not sure how good it'll be, but for $10 I'll take a chance. Watch out for antique auto swap meets, or go down to a wrecking yard; you might be able to buy a whole system for cheap off some truck or RV (horn, tank, compressor, valve).
The ultimate air supply is to adapt a car A/C compressor (York is supposed to be easiest); popular among 4-wheelers. Do a google search on on-board air and york compressor and you'll find all kinds of examples.
All this isn't exactly "easy" unless you go down to the truck or RV store and wave your credit card, but it'll be so worth it the first time some @#$%$ cuts you off and gives you an excuse to yank the cord.
I'd love an electronic airhorn, similar to what's used in emergency vehicles. Only use it in special cases, of course Nothing like 100 watts of broadband sawtooth waveform to wake up the idiot about to change lanes into you...
Wolo http://www.wolo-mfg.com/ has .wav and .au files of their horn sounds.
But, doing it electronically isn't that easy. You need a high-efficiency horn (100 to 110 dB/1w/1m) that can survive a couple hundred watts if you want to get near 130 dB outside the car. Still, an external PA horn is a worthwhile accessory for applications like verbally abusing squeegee kids and unsightly pedestrians, or playing novelty horn sounds or ice cream van tunes.
I finally bought a proper tank for my air horn(s); 5 gallons, rated to 150 psi, so hopefully I'll have system plumbed together in time to ring in the New Year.
I either want a tug-boat horn, or an "AH NU GAH" horn. has anyone seen these?
Progress - VIA EPIA SP8000 | 120 Opus Power Supply & Case | 1GB Ram | 120GB 2.5" Hard Drive | Bluetooth 2.0 | GPRS/3G | Wifi | Road Runner/LSX 2.0 (waiting for a day skin for 3.0) | iGuidance 4.0 | Lilliput 7"
Doh! you just missed $5 off and free shipping coupon code.
Ok - just installed friends horn last night. It sounds much louder than his original horn, but still not as loud as the stock horn on my Malibu. What can you expect for $10. I would look for something > 130dB.
I'm diggin the idea of using the carpc as the horn.
Here's one that might work: Sample 1