Shocker XL tuning

I have the Shocker XL kit, 6 gallon tank w/a very good compressor. This has worked flawlessly for almost 2 years, except for an intermittent leak issue at the 1/2" line going into the tank. No big deal, as I plan to move the tank and compressor to a tool box in the bed of my truck ('92 F150 XLT). Anyway, I was wondering a few things:

  1. To what notes are the bells each tuned out of the factory? I lost some things in a small flood, and all the paperwork for the kit are some of the more important things…
  2. How does one tune the bells? I’m thinking set screws that may tighten the diaphragms or something, haven’t really looked (bad back, would rather know something before I crawl under the truck, and I can’t remember when I installed them…getting old :))—I’d really like for them to sound like the Nathan P3.
  3. How much does the length of the 5/16" lines to the bells matter? Not as far as making each line the same length, but rather the length itself—what factors come into play (response, probably not so much, but what about tone or loudness)?

Looking forward to responses…love scaring the hell out of some prostitutes walking the beat muahahaha :slight_smile:



2). Don’t - mucking with the set screws voids your lifetime warranty. They don’t change tune anyway, just seat pressure of the diaphragm against the nozzle.

Welcome to the forum. DBO and a few others are very helpful.

Thank you for all that info. Very helpful. As far as line length, I was wondering if there would be much of a difference in loudness between, say, 6" from the solenoid valve and the inlets on the bells, and 2’ between the two.

Also, I read on the HornBlasters site that there are set screws that could be used to tune the bells…maybe I’m reading into it wrong (actually said something like they are tuned by way of set screws)—this would make sense to me—a tighter diaphragm would result in a higher tone…right?

I doubt I have a warranty by virtue of owning them…I imagine paperwork would be needed…maybe not. It’s loud as hell, and most people that run into brick walls or hit the sidewalk after a nice sustained blast think that it sounds like an actual train. My neighbor said it’s louder than a cruise ship. The people I work with on the 12th floor of my building said that when they first heard it from the 12th floor, they all looked outside for the barge driving down the street. :smiley:

Thanks again, and thanks for the welcome!


Oh, and yes, I am very near Ferguson…and, um…well…the train horn comes in handy :slight_smile:

The danger of tightening the screws is that they’ll warp the diaphragm if you push too far. Sure the sound might change slightly but the largest impact on sound (tune) is the shape and length of the trumpet.

The same holds true on real train horns but you can machine the throat of the horn on some of them (e.g. The airchimes) to slightly shift their tune. Nothing significant changes in volume though as a result because once again it’s the flare and shape of the trumpet which amplifies the sound.

It’s like the ol saying goes… If it ain’t broke don’t fix it :wink: if you love the sound of a Nathan P then just save up because nothing sounds like the genuine thing.

Makes sense to me. Thanks!

Perhaps I’ll experiment with some PVC

Hi again…another question…

I decided to take your advice DBO and not mess with this (tuning, etc). However, I want to put a gauge and a quick-connect (for an air hose), but it looks like I have to order the reducer fittings (hardware stores don’t have anything that big)…it looks to be about a 7/8" or so, but I cannot be sure. I tried looking it up on, but for the life of me I cannot find the model that I have. It has a 150psi regulator/relay, and the tank looks to be about 5 or 6 gallons. Again, this is second-hand and no paperwork. Is the exact model stamped somewhere that I am not seeing? Any way to find out what size inlets (threaded) or plugs are in the side of the tank?

Thanks again for all your help! Anyone else, please feel free to chime in. Pun intended!


On a 5 gallon tank, you should have 1/2" or 3/4" ports (NPT). If you run out of ports to put in additional gear, just run a 1/2" T piece.

They’re bigger than 3/4" (took fitting to hardware store—biggest thread checker they had was 3/4")—caliper says 13/16", but it still could be 7/8" (or hell, even metric), I don’t know. I wouldn’t mind buying all that I think they could be, and returning what I did not need—but I can’t find a place locally that sells them, so I am thinking I have to get them off of Ebay or something…



NPT sizes are weird.
It’s probably a 1/2" NPT port. 1/2" pipe measures .840" o.d. so the i.d. of a port would obviously be a little less.

This chart from Mcmaster Carr is a good reference.

Thank you, that is very helpful! One more question—is there a “star” or “voting” system on this forum? Because you guys have been very helpful!

Thanks again!


Nope, not really. You’re gonna find we like our horns and like helping others.

There’s just too much damn fun to be had with them!


Not sure if it works, but you can “add to somebody’s reputation”.

Each individual post has a post number. Right next to that number is a balance scale icon. Try it out!

E2E, I been here a few years now and that’s the first time I seen the scales lol!

Go to your profile page.
Above your 6 red stars you have 1 green dot.
Hover over that dot and you will see that you are “on a distinguished road”

hmmm… coool, never noticed that either. What’s the alternative I wonder - a brown dot with “you are on a slippery slope” :smiley:

Yet another question…what is the name of the deal that the hose connects to the tank with (with the thing you pull out—1/2"NPT male on one end, hose goes into other end, and a deal that you push in toward the tank to release the hose, but only when the tank is empty)?

I’ve heard a couple of terms for them, Instant Tube Fittings & Push to Lock Tube Fittings.

Most common term I see is PTC fittings.
Push To Connect