Lower frequencys

I know your not meant to play below 50-45hz in 1850s because it will over exert the driver.
Could anyone tell me why this happens in folded horns?
Is it because the driver has to push so much volume around?
Also when/why does damage occur?
I could use some clarification

the frequency range from a horn is made by the lenght, throat and mouth area of the horn, if you want to go lower than 1850 you need a longer horn with bigger mouth, look here for exemple i take 186 vs 186with bigger mouth, throat and longer horn:

Edited by dj-panoramix - 24 October 2009 at 3:30pm

it just wont reproduce lower frequencies than the horn is able to.
the excursion will rise but not the output...
worst case is you damage the speaker with overexcursion, but u will hear it working hard when u try to play it too deep.
if u use more horns the horn mouth will be acoustically bigger so u can use them lower too.
4 1850s stacked should reach nearly 40hz. subsonic at 35hz and you`ll be fine.
cheers

ok thanks.
panoramix, can you post a shot of the parameters you used for that plot :D