So I am a carpenter i have all the tools and material i could ask for when looking to build a sub enclosure. Now I need someone much smarter than I to help me design it. I want to build a 5th order bandpass specific to my subs and amp. If anyone has any experience or advice on the subject it would be much appreciated. Ill have to check specific model but I have 2 Polk audio 12's that I believe are 350w rms each. I have a rockford fosgate 700bd1 amp powering them.
You said you wanted someone smarter than you to help, well here are some proffessionals and their thoughts on bandpass enclosure, the guys at JL Audio,
JL Audio header Support Tutorials Tutorial: Bandpass Enclosure Characteristics
Read through that, the bandpass enclosure is horrible for everything but sheer output plus they are extremely unforgiving if you make the slightest mistake in construction or size calculations, don't listen to the schlubbs that tell you "go bandpass" "go ported" maybe it will be loud but will sound bad. Unless you are going for competition of course, if you are interested in a high quality sound that has plenty of output just go with a manufacturer recommended ported box, or a sealed if you are willing to trade off a little SPL for a little SQ. the advantages you gain from a bandpass box can easily be achieved with more power or better subs plus you will avoid all the headache and uneven frequency response, not to mention bandpass enclosure especially the dual reflex ones mess up your subwoofers with too much power and you won't even know anything is wrong until your woofer is blown my 2 cents
JL Audio header Support Tutorials Tutorial: Bandpass Enclosure Characteristics
Read through that, the bandpass enclosure is horrible for everything but sheer output plus they are extremely unforgiving if you make the slightest mistake in construction or size calculations, don't listen to the schlubbs that tell you "go bandpass" "go ported" maybe it will be loud but will sound bad. Unless you are going for competition of course, if you are interested in a high quality sound that has plenty of output just go with a manufacturer recommended ported box, or a sealed if you are willing to trade off a little SPL for a little SQ. the advantages you gain from a bandpass box can easily be achieved with more power or better subs plus you will avoid all the headache and uneven frequency response, not to mention bandpass enclosure especially the dual reflex ones mess up your subwoofers with too much power and you won't even know anything is wrong until your woofer is blown my 2 cents
Actually, my last post was intended as a bit of a taunt as there is no agreed upon definition (to my knowledge) as to what "orders" are. Check out the thread here > need help with abc enclousure for pair octane r12d and you will see what I mean about "orders" and bandpass enclosures in general.
That thread only adds to the confusion just because one person doesn't like the nomenclature that already exists. Adding Xovers changes the order because the total order of the bandpass enclosure is DIRECTLY related to the roll-off on both the low and high end of the passband. If one end is now steeper due to passive xover, it has a greater slope, thus order, just as crossovers do. It doesn't add additional resonances, which is what you seem to think that others think that, but no one ever said the additional order added extra resonances.
Ever heard of a 6th order bass-reflex vented enclosure? They exist. Their order is 6. It is not a bandpass. The roll off is -36dB/octave. Does it have two different Fb's just because the order is "6"? Nope, and no one ever said it did.
http://www.xlrtechs.com/dbkeele.com/PDF/Keele%20%281975-07%20AES%20Published%29%20-%20New%20Set%20of%20VB%20Alignments.pdf
No, it doesn't work that way. I can read between your lines, and you want me to start with a number for the order only, and then describe a single type of enclosure that it maps to. It doesn't work that way. Both you and I know that. [For the mathematically inclined, the mapping for order-to-enclosure-type is not a one-to-one (injective) function 
).
Perhaps you are not truly understanding what I am saying. Maybe you are, I don't know, but I'll explain myself, just promise to put the whiskey down a few hours prior to reading my explanation....
The only thing that I am saying is this...I will try to word it as clear as I possibly can...
IE:
Notice the bold part above. What I am saying, just as the original thread starter did, is state the specific enclosure type along with the order to describe the overall system. Thread starter never said that the numerical order is all that is needed for us to decipher which specific enclosure he needed.(!)
Since the thread starter originally (and specifically I might add) stated his design is to be a bandpass of order 5, it doesn't take a genius to realize that a 4th order bandpass is the lowest order bandpass possible (mechanically) , and since it is to be a 5th order bandpass, it must have an additional -6dB/octave of rolloff somewhere (because the unmodified design is 4th order to begin with).
Now, if he had said 6th order bandpass, then that might be misconstrued as ambiguous because there is a dual-reflex 6th order bandpass (two distinct port resonances), or it might just be a 4th order bandpass with an additional 2nd order filter. But this isn't the case in the original post...
I think you either read the original post incorrectly, or read some post by some numbnuts on some other forum referring to his bandpass box as a "4th order" and perhaps thought that was going on here. Rest assured, it is not.
).Perhaps you are not truly understanding what I am saying. Maybe you are, I don't know, but I'll explain myself, just promise to put the whiskey down a few hours prior to reading my explanation....
The only thing that I am saying is this...I will try to word it as clear as I possibly can...
- The numerical order along with the enclosure type is a perfectly valid way to describe the overall system.
IE:
- 4th order bass-reflex (vented): just your normal, standard, everyday ported enclosure, rolls off -24dB/octave below F3
- 6th order bass-reflex (vented): a vented enclosure with an addition 2nd order filter to further increase the roll-off rate, -24 dB/oct + (-12 dB/octave)= -36 dB/octave
- 4th order bandpass: single-reflex bandpass (one port tuning) with a natural 2nd order roll-off below F3L, and natural 2nd order rolloff above F3U. 2nd order + 2nd order = 4th order total
- 5th order bandpass= simply a 4th order BP with an additional 1st order filter on the upper-end to attenuate higher frequencies above F3U. -12 dB/oct on the low-side, -18dB/oct on the high side = -30dB/octave total = 5th order (total)
- ad infinitum.....
Notice the bold part above. What I am saying, just as the original thread starter did, is state the specific enclosure type along with the order to describe the overall system. Thread starter never said that the numerical order is all that is needed for us to decipher which specific enclosure he needed.(!)
Since the thread starter originally (and specifically I might add) stated his design is to be a bandpass of order 5, it doesn't take a genius to realize that a 4th order bandpass is the lowest order bandpass possible (mechanically) , and since it is to be a 5th order bandpass, it must have an additional -6dB/octave of rolloff somewhere (because the unmodified design is 4th order to begin with).
Now, if he had said 6th order bandpass, then that might be misconstrued as ambiguous because there is a dual-reflex 6th order bandpass (two distinct port resonances), or it might just be a 4th order bandpass with an additional 2nd order filter. But this isn't the case in the original post...
I think you either read the original post incorrectly, or read some post by some numbnuts on some other forum referring to his bandpass box as a "4th order" and perhaps thought that was going on here. Rest assured, it is not.
That is exactly what I am saying. Such and such an order is not the same as stating the type of enclosure. People have, and do, interchange the two. To much ambiguity here. To me, it makes MUCH more sense to say "single reflex w/ a 12db LP filter" than to say "6th order". ANY nomenclature that has such a wide area for confusion should not be used, at least not without some clarification. At which point, why bother.
And this is why, when asked "What enclosure should I build", suggesting a particular "order" can get confusing. Unless the "order" suggested is broken down into enclosure type and additional components used, it shouldn't be used.
Regardless, unless someone has the ability to actually measure the T/S parameters (mfg. spec sheets are notoriously off) of the driver that is intended to be used and the required skills to exactly build the enclosure to specs, they really shouldn't waste the time and money.
esayest way i recon with out aiming for perfection is just match the speacker to a like 1 in household cabinated 1 just for esay nice box ive done this an it sounds pretty nice old 1s are best the ole plussey stuff XD cheap but sort of nice
and look at the many boxes used and the old crt tv sound boxes used
some 1 has already done some fancy stuff out thea u just gota find it and clone away also cheak patents on stuff jbl and others will give u some clues XD
but if experimenting try using already in use boxes and making adapotors XD
i have the mintest idea for a sub box i think it mite auctulay cause survre damages XD
and look at the many boxes used and the old crt tv sound boxes used
some 1 has already done some fancy stuff out thea u just gota find it and clone away also cheak patents on stuff jbl and others will give u some clues XD
but if experimenting try using already in use boxes and making adapotors XD
i have the mintest idea for a sub box i think it mite auctulay cause survre damages XD
doesn't each order refer to a control element that effects the cross over point? e.g sealed box is 2st order because you have the spring of the air in there enclosure and the mass of the air to control the high pass, ported is that plus the springiness and mass of the air in the port, standard band pass is that plus the spring and mass of the sealed enclosures which is 6th order etc. each added order increases the cut off rate, just like a passive electronic crossover. I could be wrong tho
each order does increase the total cutoff rate, but a standard sealed/ported bandpass is not 6th order, it is 4th order--12 db on the highpass and 12 db on the lowpass.
no need to worry, thump lump was mistaken about the context of the word "order" because it wasn't being used the way he thought it was---the OP was using it in conjunction with the enclosure type to designate the overall system
Really? I fail to see any other reference to an "order" other than the enclosure.
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