The model 230 and 630 train horns are the loudest. The output is about 153-154 dB at 150 PSI. However if you use the Model 6880 BlastMaster upgrade, (supplies 2 extra solenoids, fittings and tubing so each trumpet will have its own solenoid) the output will go up to about 157 dB. This is just about as loud as train horns will get!
Models 230, 630, 500, and 501 will sound like a real train horns. The model 220 dual train horn will be close but it is a dual tone instead of a three tone so it will not be an authentic train horn sound like the others.
Some vehicle will be able fit some air horns under the hood or behind the grill but most customers will install the air horns underneath the vehicle on a body rail. The air horns should be angled slightly downward to allow excess water to drip out of the trumpets.
As long as the sealed compressors are being used, they can also be mounted underneath the vehicle on a body rail. The sealed compressors can be mounted in any position except uPSIde down and the remote intake filter should be placed somewhere clean and dry.
Although the larger train horns tend to be louder, all of the air horns will be in the same range in terms of the dB output. They all will put out 146 – 154 dB. However, because of the smaller, narrower trumpets, the sound of the smaller air horns (99, 102, 130, 141) will be a higher pitch than the larger train horns (220, 230, 630, 500, 501).
Choosing a compressor is less about the air horn and more about how the air is going to be used. Start with the 6275. It is the mid-range compressor and can be used with any air horn. If a customer is looking for a lower cost item and is willing to sacrifice some loudness the 6260 or 6270 will work with any air horn with exception of the 230 and 630 train horns (Kleinn recommends using 150 PSI systems with those train horns). If a customer is looking for more capacity and/or would like to use the air for tire inflation, air tools, etc., the 6350 will work with any air horn.
In terms of sound, there is virtually no difference between the metal and ABS air horns. Many customers prefer the ABS air horns because they are more durable for mounting underneath a vehicle. However the metal air horns with usually look better because of the chrome finish. It is more a matter of preference than a matter of quality.
The only air horn models that do not need a compressor/tank system are Kleinn's direct drive models 6126 and 6127. They come with a direct drive compressor that will pump air directly into the air horn instead of pressurizing it in a tank. These air horns will be louder than a stock horn but not as loud as the air horns that use a separate compressor/tank.