Adding a sub to a ported speaker

[Sergio123]

Hi all!
This is my first post here so please be gentle...
I do not understand what happens to the port of your speaker if you add a (sealed) subwoofer to a ported speaker.
As I understand, port gives you the lowest frequencies that the driver in the sealed box could not produce.
Now of you cut off the frequencies under say 80 Hz because your sub now plays them, does it mean that your port in ported speakers does not have any function any more?
I hope I could explain my question...
Thanks!

 

[rayma]

The port shouldn't have much output then, if the cutoff is sharp enough.

 

[Sergio123]

Thanks! And if making my own speakers, can I tune that port to have output at higher frequency? Perhaps 80, 90 or 100 Hz? Would that make sense?

 

[Sergio123]

But still, I do believe that the port would still be producing its own frequency, yet the driver would not go under the crossover frequency... Does this sound right?
I am no expert in speaker boxes by any means, just this makes sense to me...

 

[rayma]

You could retune the port, but that may not be necessary.
The port should only produce output when there is some bass content in its tuning region,
so the filter would remove that. Try it like is now, with the sub and see.

 

[AllenB]

Regardless of these factors, the presence of the port is going to start you with a steep rolloff and a more complex impedance curve. In some cases it makes sense to block the ports before crossing for simplicity, and for reducing group delay.

 

[rayma]

Right, I seldom like ported speakers myself.