First of all, this doesn't have anything to do with my Camaro, but...

Okay, I'm dorky. Harbour Frieght sells Oooogah horns that operate on 12 volts. This week they were half off; so yours truly decided to pick one up for his daily driver truck. I wired it up temporarily to test it out. It sounds WAY too fast. My friend had an authentic 30s or 40s one and it was MUCH more throaty and "slow," and his was designed to operate on 6 volts. I'm wondering if I could run a resistor in-line on the positive to help slow it down and give it better tone. If so, what one should I go with? I'm thinking that dropping it down to 8 or 9 volts would do the trick. I currently have it run through a relay and a "10" fuse. Any suggestions would be greatly appreciated!

First guess a ballast resistor for a coil. Like an old Mallory, or a Chrysler, may work.
They were to drop voltage to about 9v. You will need one that can can take a medium
amout of power.

So I need a ballast resistor! Looked at AutoZone's website and they've got a few models to choose from. Anyone have any idea which one I should go with?

http://www.autozone.com/autozone/catalog/accessories/accessoriesShelf.jsp?categoryDisplayName=Performan ce&fromType=accessories&fromString=search&parentId=cat10034&filterByKeyWord=ballast+resistor&currentPage=1&navValue=100781&categoryNValue=100008&fromWhere=&subPartId=prod13174&itemId=prod13174&displayName=Ballast+Resistor

If you get a higher ohm resistor less voltage will get to the horn. Other than that, just pick one that will mount well for you.

I am not sure how your horn works, but I think you will find that less voltage makes it quieter not slow. But I don't know...

The horn is pretty loud and it'a motor-driven. I though a lower voltage would turn the motor slower' making the horn sound slower. According to the package, the horn puts out 120dB; so of it dropped in volume, I'd probably be okay.

My buddy has an authentic horn in his 12-volt Jeep, and it sounds pretty good. When we installed it in his '51 Chevy, the sound dropped in speed. I attributed it to being on the Chevy's 6-volt system. It sound much better now than it did in the Jeep. I wonder why they didn't build the new horn to better replicate the older horn's sound.

I don't know how the system works, and if it has a separate compressor or motor or whatever you are probably right.
Give it a try...

Thanks, guys. I looked at various horns on YouTube and came to the conclusion that it's just the type of horn I got. A ballast resistor will help slow it down, but it'll never be as throaty as and old school ooogah. Guess I'm going to have to hunt eBay for what I want!