4th Orders...

[obxsurfisher 10+ year member]

I just have a question about 4th order boxes. I see lots of installs with them and I hear (and read) that they're good to use for the lows. But what I don't understand is how they get low if the lows are coming from the sealed chamber. Sure sealed box's can get low, but usually a lower tuned ported box has better low end extension. So whats the difference between a sealed enclosure and 4th order when it comes to the low bass?

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[vetkilr 10+ year member]

A properly tuned 4th order works on a narrowed freq. range. The sealed side is for lows and cone excursion/control.The ported side controls where the highend rolls off. It is sort of like one freq bounces off the other and boost the range in between the two freq., thus causing a artificial boost that can be tuned by tuning the sealed and the ported side to adjust the boost spot.

About as basic as I can explain without getting all techinical.

 

[obxsurfisher 10+ year member]

A properly tuned 4th order works on a narrowed freq. range. The sealed side is for lows and cone excursion/control.The ported side controls where the highend rolls off. It is sort of like one freq bounces off the other and boost the range in between the two freq., thus causing a artificial boost that can be tuned by tuning the sealed and the ported side to adjust the boost spot.
About as basic as I can explain without getting all techinical.

Thanks, so the ported part is where you get the boost in those freq's usually tuned between 40-50 right? So, these boxes don't necessarily get lower than a low tuned ported enclosure, they just have a "boost" around where the ported section is tuned to?

 

[vetkilr 10+ year member]

a boost lower then ported tuning...mine is tuned to 46hz and 32-35 is where mine peaks at. Each one is different, how big the port is and how big the ported side is effects where and by how much the boosted or more efficient range is.

 

[obxsurfisher 10+ year member]

a boost lower then ported tuning...mine is tuned to 46hz and 32-35 is where mine peaks at. Each one is different, how big the port is and how big the ported side is effects where and by how much the boosted or more efficient range is.

Oh ok, that's interesting. Thanks for helping me understand. How does one go about designing one? I have torres but i think that's just for ported and sealed designs.

 

[vetkilr 10+ year member]

Lots of practice...there are certain rules, but alot depends on alot...subs included.