Basics of a 4th order bandpass enclosure

[donellk]

my biggest concern is how do you know if a woofer will work well in a bandpass enclosure? please explain this detail for me and others.

That would be another advantage of having bassbox pro! You can type in all the specs of the woofer and plot out the performance of that subwoofer in the 4th order! Lol they should hire me for advertising lol! I guess the quickest way would be with a call or email to the manufactor they'll be able to tell you if itll work and sometimes even give u recommended specs! Before I designed the one I built I talked to my power acoustik sales rep!

[donellk]

Sorry to be the idiot of the group, but what are the Fs and Qts?

Check out the bottom of this page

http://www.diysubwoofers.org/definitions.htm

[6berry]

Sorry to be the idiot of the group, but what are the Fs and Qts?

the Fs and the qts are part of the T/S parameters. Fs is resonant frequency. im not exactly sure what the qts is but it plays a big part in deciding whether a driver will work in sealed, ported, or free air

[scooter99]

Thanks guys!

[Sanitarium]

i really REALLY wish people would stop hugging up to the whole ratio thing.

dumbasses squeezing down the sealed side in search of a higher ratio/more peak.

Seriously. build the sealed side to spec/desired F3. then build ported side to accomodate taste. peaky or flat is up to you.

Throw the whole notion of ratios out the damn door.

So what you are saying is just build the Ported side to your liking?

My 4 12's are in a sealed box right now but i have two seperate chambers for each pair of subs, could i turn this box in to a 4th order?

If you really want to be that ghetto and glue your current box onto a ported box thats built correctly, go for it.

Oh and on a regular ported box you tune lower due to the sin wanting to unload below tuning. This wrong happen with a 4th order.

[UnderLoK]

i really REALLY wish people would stop hugging up to the whole ratio thing.

dumbasses squeezing down the sealed side in search of a higher ratio/more peak.

Seriously. build the sealed side to spec/desired F3. then build ported side to accomodate taste. peaky or flat is up to you.

Throw the whole notion of ratios out the damn door.

So what you are saying is just build the Ported side to your liking?

My 4 12's are in a sealed box right now but i have two seperate chambers for each pair of subs, could i turn this box in to a 4th order?

If you really want to be that ghetto and glue your current box onto a ported box thats built correctly, go for it.

Oh and on a regular ported box you tune lower due to the sin wanting to unload below tuning. This wrong happen with a 4th order.

So what consideration then do you give the cabin? I ask because the big 4ths I've been in would shit the bed if you were to open a door. That leads me to believe (by your comment) that you can do something to prevent that from happening.

[Punkeyboozter]

i really REALLY wish people would stop hugging up to the whole ratio thing.

dumbasses squeezing down the sealed side in search of a higher ratio/more peak.

Seriously. build the sealed side to spec/desired F3. then build ported side to accomodate taste. peaky or flat is up to you.

Throw the whole notion of ratios out the damn door.

So what you are saying is just build the Ported side to your liking?

My 4 12's are in a sealed box right now but i have two seperate chambers for each pair of subs, could i turn this box in to a 4th order?

If you really want to be that ghetto and glue your current box onto a ported box thats built correctly, go for it.

Oh and on a regular ported box you tune lower due to the sin wanting to unload below tuning. This wrong happen with a 4th order.

So what consideration then do you give the cabin? I ask because the big 4ths I've been in would shit the bed if you were to open a door. That leads me to believe (by your comment) that you can do something to prevent that from happening.

I think that is for extreme cars where the cabin actually forms part of the box. So essentially they are taking the reading in the port and hence the crazy numbers they post. Open the door and the tuning will go whack

[mlstrass]

subs with very stiff suspensions are not 4th order friendly......like HDC's and 9500 DD's.

[MrSkippyJ]

Now here is where it gets fun... Your subwoofer needs to come from the sealed section facing into the ported section.

This strikes my curiosity. I have seen tons of 4th orders with subs inverted.

[Punkeyboozter]

Now here is where it gets fun... Your subwoofer needs to come from the sealed section facing into the ported section.

This strikes my curiosity. I have seen tons of 4th orders with subs inverted.

I think inverted is better, you can smell the coils if you screw up and it helps with the cooling.

Im still wondering how much port is enough. They say to go for at least the same amount as cone area but then you get ridiculous port lengths and without screwing the gain its hard to maintain.