help building box for sundown 6.5 ported

[smitty33]

I want to build a ported box for a polaris rzr that ports through a little access panel between the seats and hide the box OUTSIDE of the cabin behind the cabin in between the engine and cabin. Plenty of space and I can make it weather proof and all that. Question is can I make a 1:1 bandpass type box or does it need to be a 2:1 to sound right?  I need to keep the voicecoil out of the dust/elements so I can make the sub last. So if i seal the sub and fire it into another chamber thats ported into the cab it would be ideal for my needs. Sub is a sundown sa 6.5 on 300 watts so i really want to get the most bass i can ideally. Thanks far any input fellas.