Why 4th order bandpass

[varietyguy]

cant speak on 6th orders but for a 4th i say the sealed side is huge!!!

i would also 180 the sealed part so the sub is facing the loading/port wall

and Hotdog yes more output less bandwith but 4th play pretty flat no matter

I was having a huge mental debate on this or what I ended up doing. The other thing I was worried about and couldn't find too much info is the port. I was informed that with a 6th order the port should be very small to compensate the "punchy" affect. So the enclosure is 25 sq inches which is about 8 sq in of port per cube. Then the loading chamber is right at 15 sq in per cube.

[Ddub847]

6th order looks nice. Let me know how it turns out.

[ALPINE408]

again i can't speak on 6th orders but all the extrem guys doing 180 dbs had the 4th and 6th order subs facing the loading wall

i have built 2 6th orders in my time both failed so i can only tell how not to build one lol

[old dude]

There is no formula for a 4^th or 6^th order box that is going to tell you how well the box will work in the real world. Those formulas are only made by someone with excel and an opinion. Even if the guy making up the formula has tons of experience with 4^th order builds he still can not tell you how it will perform in your car/suv.

So if you want to get good at building 4^th order boxes jump on it man all it takes is a starting point and lots of building testing and rebuilding and more testing and more rebuilding and more testing. It also helps if you understand waves and the power of a wave which is amplitude and conical waves. All the while remembering that your vehicle where the box is going into represents yet another chamber. That chamber also can be sealed or ported depending on whether you have the windows up or down.

As for the resonant frequency of your vehicle remember that what makes it resonate is the energy being produced by the subs so every slight change in power changes the resonant frequency of your vehicle. Your car has no such thing as a certain resonant frequency what it does have is thousands of different possible frequencies that it can resonate at depending on what you subs are doing as far as power and frequency played inside.

[Hotdog]

There is no formula for a 4^th or 6^th order box that is going to tell you how well the box will work in the real world. Those formulas are only made by someone with excel and an opinion. Even if the guy making up the formula has tons of experience with 4^th order builds he still can not tell you how it will perform in your car/suv.

So if you want to get good at building 4^th order boxes jump on it man all it takes is a starting point and lots of building testing and rebuilding and more testing and more rebuilding and more testing. It also helps if you understand waves and the power of a wave which is amplitude and conical waves. All the while remembering that your vehicle where the box is going into represents yet another chamber. That chamber also can be sealed or ported depending on whether you have the windows up or down.

As for the resonant frequency of your vehicle remember that what makes it resonate is the energy being produced by the subs so every slight change in power changes the resonant frequency of your vehicle. Your car has no such thing as a certain resonant frequency what it does have is thousands of different possible frequencies that it can resonate at depending on what you subs are doing as far as power and frequency played inside.

that is where the Dayton audio dats comes into play it takes the guess work out of finding you resonance of the sealed chamber. It runs a sweep to find it. The tool is also used to find the parameters of the subwoofer.

Dayton Audio DATS Dayton Audio Test System

The highly successful Dayton Audio WT3 speaker tester has now outgrown its name! DATS, the Dayton Audio Test System, is the proud successor to the WT3, includes everything WT3 users have come to love about that system—but adds much more. Don't worry, the new system still measures loudspeaker parameters or R, L, and C values in just seconds and still includes the WT3's unique Rub and Buzz test. But now with the introduction of DATS, the system has grown beyond impedance testing and T/S measurements to include a second test mode featuring a general purpose signal generator and oscilloscope working in tandem.

The scope and generator combination provides a powerful general purpose audio test set. When used with the DATS hardware, the oscilloscope monitors the DATS generator output and is calibrated. When standard audio interfaces are available, the oscilloscope input can be switched to another device to allow the monitoring of arbitrary input signals in addition to the DATS generator output.

[Hotdog]

[old dude]

There is no formula for a 4^th or 6^th order box that is going to tell you how well the box will work in the real world. Those formulas are only made by someone with excel and an opinion. Even if the guy making up the formula has tons of experience with 4^th order builds he still can not tell you how it will perform in your car/suv.

So if you want to get good at building 4^th order boxes jump on it man all it takes is a starting point and lots of building testing and rebuilding and more testing and more rebuilding and more testing. It also helps if you understand waves and the power of a wave which is amplitude and conical waves. All the while remembering that your vehicle where the box is going into represents yet another chamber. That chamber also can be sealed or ported depending on whether you have the windows up or down.

As for the resonant frequency of your vehicle remember that what makes it resonate is the energy being produced by the subs so every slight change in power changes the resonant frequency of your vehicle. Your car has no such thing as a certain resonant frequency what it does have is thousands of different possible frequencies that it can resonate at depending on what you subs are doing as far as power and frequency played inside.

that is where the Dayton audio dats comes into play it takes the guess work out of finding you resonance of the sealed chamber. It runs a sweep to find it. The tool is also used to find the parameters of the subwoofer.

Dayton Audio DATS Dayton Audio Test System

The highly successful Dayton Audio WT3 speaker tester has now outgrown its name! DATS, the Dayton Audio Test System, is the proud successor to the WT3, includes everything WT3 users have come to love about that system—but adds much more. Don't worry, the new system still measures loudspeaker parameters or R, L, and C values in just seconds and still includes the WT3's unique Rub and Buzz test. But now with the introduction of DATS, the system has grown beyond impedance testing and T/S measurements to include a second test mode featuring a general purpose signal generator and oscilloscope working in tandem.

The scope and generator combination provides a powerful general purpose audio test set. When used with the DATS hardware, the oscilloscope monitors the DATS generator output and is calibrated. When standard audio interfaces are available, the oscilloscope input can be switched to another device to allow the monitoring of arbitrary input signals in addition to the DATS generator output.

Yes the DAT has some features that I like for modeling and some for keeping track of data for future modeling. Using a tool such as the DAT or even a simple decibel meter will prove beyond any doubt that power and frequency are what determines how an object resonates. Also proving that there is no such thing as A resonant frequency of a car or any other object on earth. Anything that resonates will be affected by power and frequency thus there is not a given state but only a state of resonance that changes with every little turn of the knob on your head unit.

Again the DAT will only prove that there is no such thing as one resonant frequency of a car or for that mater the sealed chamber of a box unless of course you never change your volume or frequency being played.

[quakecitystudio]

http://www.the12volt...udio/boxes4.asp - has some pictorial examples of 4th orders, but I think what you are seeing most often are variations of the "three chamber single reflex bandpass enclosure"

I will say this first, that I have not built a 4th order like above, but after looking at some examples on here, it seems like most are getting great results as well as visual appeal; high air flow due to port velocity especially from a wall setup, and the look of a cavity of woofers staring back at you.

As far as building one, I'm curious if the very first 4th order single reflex started as a couple of sealed boxes built to spec for the woofers going in them, subs positioned to face each other from a short distance, and then topped and bottomed with a sheet of wood to direct the sound forwards. This is often used in a club where space is not an issue for big bass sound.

When I say variations, I mean slanted walls with woofers facing each other, inverted, or firing forward, ported rear chambers, etc.