5 Important Horn System Builder Tips
1.) The Sound
The sound of the horn is typically the first and most important consideration when deciding on an air horn system. You will want to consider how loud you want the horn to be, and if you are looking for a particular sound (e.g. train horn, truck horn, musical, etc).
How loud do you want it?
There are two general types of air horn systems that are popular. The first is a direct drive system which includes a small air pump about the size of a soda can which pumps air directly into a small set of horns. These systems are great for small applications such as motorcycles or golf carts. They will be louder than a standard car horn, but they will not get the extreme loud sound that many buyers are seeking. The second type of system uses an air compressor and tank. The compressor builds pressure in the air tank to anywhere from 110-200 PSI. The tank holds that pressure until the horn is triggered, usually by an electronic solenoid installed on the horn. This type of system is much louder. Blasts from these types of horns are typically 148-153 dB. Some systems can reach up to 157 dB depending on the type of horn, size of the valve and the air system. Some sellers advertise horns that go to 170 dB, 180 dB, etc. Those levels are just not attainable for these systems so take that information with a grain of salt when making your purchasing decision.
What Kind of Sound Do You Want
Generally speaking, the type of sound generated by a set of horns depends on the size of the individual trumpets and the number of trumpet in the set. Trumpets that are shorter and thinner will produce a higher pitched sound, and trumpets that are longer and wider will produce a deeper tone. Usually the horns with come as a set of 2, 3, or 4 trumpets which are designed to make a blended tone. The traditional “train horn” sound is produced with 3 large trumpets with wide bells (at least 6″ wide). There are several smaller sets of horns available in online shopping that have 3 or 4 smaller trumpets and are advertised as train horns. These kits can sound nice and can be very loud, but they will produce a sound that is much higher pitched than a traditional train horn due to the size of the trumpets.
2.) Air Requirements
There are 3 important features of the air system to consider: The working pressure, the tank capacity, and the compressor duty cycle.
The general rule for an air horns system is the higher the air pressure, the louder the horn will be. That being said, we’ve found that the increase in sound tends to plateau after about 150 PSI unless you upgrade the valve on the air horn to a 3/8″ or 1/2″ valve.
The amount of air stored in the air tank will determine how long you can hold the horn blast before the tank has to refill. For reference, a 1 gallon air tank filled to 150 PSI will give you about a 4-5 second blast before the compressor will turn on to refill the tank.
Compressor Duty Cycle
All compressors have a duty cycle rating which is calculated by the maximum run time as a percentage of a complete on/off cycle.For example a compressor that has 25% duty cycle can run for up to 15 minutes straight, but then must cool for 45 minutes. 15 minutes is 25% percent of the complete 60 minute cycle (15 minutes on + 45 minutes off). Things to take into account when considering the proper duty cycle are:
- Tank size – larger tank require heavier duty compressors
- Expected frequency of use – The more you use the horns, the more the compressor will be running
- Multi-purpose air – If you plan to use the air system for things other than horns, such as tire inflation or air tools, a 100% duty (continuous duty) air compressor is recommended.
3.) Sealed vs. Non-sealed Air Systems
One of the most common reasons that air horn systems malfunction is that the air compressor was installed in an inappropriate location. Most of the popular air horn kits include compressor and tank systems that must be mounted in a clean and dry location. If they are mounted in an exposed area, dirt, dust or water can make its way into the piston chamber and damage the compressor. This type of damage usually is not covered by seller or manufacturer warranties. To remedy this issue, some systems are offered with a “sealed” air system (Example). The various chambers of these compressors are sealed with gaskets so that they can be mounted externally on the vehicle’s chassis. They include tubing and hardware to mount the compressor’s air intake in a clean and dry location so dirt, water, etc. does not get drawn into the compressor. The sealed kits can be a bit more expensive but it is worth the investment if you plan to mount the compressor externally.
4.) Installation Space
When choosing an air horn kit you should have an idea of where you are going to mount the components. The most common locations are in the engine compartment or underneath the vehicle on the frame rails. The air horn kits available vary greatly in size so make sure to look at the dimensions of the components to make sure they will fit your application.
5.) Do-It-Yoursel for Professional Installation
Once you pick out your air horn kit it’s time to decide if you should install it yourself, or take it to the shop. The answer depends on your level of experience. In terms of the wiring and installation, air horn kits are relatively straight forward for people who have some experience with 12-volt installations. Usually the most challenging part of the installation is deciding where to mount all the components (it may take some creativity depending on how ambitious you were with the size of the air horns you picked out). When we get this question we’ll typically ask these questions:
- Have you ever installed anything in you a vehicle before
- Do you know how to use a test lamp or volt-ohm meter
- Can you find the fuse panel in your vehicle
- Do you feel comfortable drilling a hole in the vehicle frame
If you answer “no” to any of those questions it is recommended that you take your system to a professional automotive electronics or truck accessories installer.