I started with an Omega AH-500 5-trumpet horn set, 1 gallon, 110 psi, connected with a mix of 1/4" and 1/8" inside diameter (ID) rubber air hose and brass fittings. It was loud and a lot of fun but I wanted a longer duration so I upgraded to 7 gallon, 150 psi, and everything 1/4" ID hose and fittings. It was just a bit louder and the duration was great but I was still disappointed that there wasn’t more volume considering all the muscle I put into the system. So then I upgraded the horn to the Shocker XL kit and stepped up to a mix of 1/4" and 3/8" ID hose and fittings. This was a much deeper tone like a real train but still about the same overall volume as the Omega AH-500. Something just wasn’t right.
After a lot of calculations and research I determined that 1/2" ID hose and fittings were required. I just finished the upgrade tonight and everything is 1/2" ID including the fittings, couplers, manifolds, adapters, hoses, valves, etc. The line only steps down just as it enters each trumpet of the horn. I test fired it just now and YEEEAAAA GAWWDD that was loud! Easily double the volume of my previous setup and I didn’t change the tank, compressors, psi, or horns at all.
On all of my previous setups I could stand beside the vehicle and honk the horn. It was loud but I could take it and my ears didn’t ring at all. With the new setup it is painful to fire the horn while standing outside the truck. My ears were both ringing (and still are) after just a 2-second blast. So then I reconnected the Omega AH-500 horn and tried it out. It was unbearably loud, so much so that I could only take a 1-second blast and I had to quit. So now I am going to have both horns on the vehicle and a switch to fire one, the other, or both. But I am going to sound it from inside the truck with the windows mostly up and nobody standing nearby outside.
Moral of the story: if you want more volume then start by upgrading your air line to a larger inside diameter and keep all of the hoses, tubes, fittings, valves, manifolds, adapters, etc. all the same size. Go with 1/2" ID rubber air hose for the best results (it is larger inside than 1/2" OD nylon tube). It may cost a bit more for all the connectors and you may have to hunt around to find them but it truly is like getting a whole new horn system. Wish I had done this 2 years ago!
The Omega AH-500 horn came as a kit with 1-gallon tank and compressor from Hornblasters. It was called the “Conductor’s Special” at the time but is no longer available. The Shocker XL kit and an extra Shocker XL valve came from Hornblasters as well.
I picked up the 7-gallon aluminum air tank from Harbor Freight. Air Zenith digital pressure gauge from some place on the web, might have been KMW performance, can’t remember for sure.
1/2" quick-disconnect couplers were found at Northern Tool & Equipment - they are HUGE! Most of the brass fittings and adapters came from Lowes along with the Goodyear rubber 1/2" ID hose - all in the plumbing section. I will be posting a more detailed write-up soon with pics now that I have finished the final trim work.
Tank outlet is 1/2" NPT. Inlet on the Shocker XL HB4H is a 4-port splitter which takes 1/2" NPT from the compressor and feeds four 5/16" nylon tubes, one to each trumpet. Inlet on the Omega AH-500 is 1/4" NPT.