at what point does the frequency become too high to be effective for spl testing? what is the best frequencies to use(hi-low)and how much of it depends on the vehicle? [img]graemlins/dunno.gif[/img]

it all depends on the vehicle, but lower frequencies will create more heat in the voice coil.

Trial and error is usually the easiest way unless you are able to actually run the numbers and find the ultimate freq between the resonance point of the vehicle and tuning of your enclosure...?

it all depends on your car , from the back of the car to the middle u can gain from 4-12db providing your not stuck inside the trunk , box placement is another factor , but like what above says trial and error dude

i've come to learn that it's usually more trial, less error, and a lot of luck!

one million hertz