What is a Resonator?

Answer: A resonator on a Truck is a hollow chamber in the exhaust tract. Its location is placed a certain distance from the muffler and engine to allow the resonant effect. This is to dampen parts of the noise coming from the engine and enhance other parts of it. Truck makers tune the location of this resonator to tune the sound of your exhaust to better match the nature of your car ie sporty(loud) vs luxury(quiet) exhaust.