Three Chamber Single Reflex Bandpass

metaljoey · 09-22-2010

i am looking at a Three Chamber Single Reflex Bandpass with 4 American bass XFL 12"s for My build. the trunk of my 04 sebring will be walled off. leaving the port firring in the cabin. i looked it up, and this is what it stated.

"The single-reflex band pass enclosure is basically a combination of a sealed and vented enclosure. These can be fairly small enclosures, though larger than a sealed enclosure. They offer great power handling, good low frequency response, but are not as efficient as vented enclosures, and are more complex to build. However, when built correctly, these make excellent enclosures and are often used by competitors. This is often referred to as a fifth order enclosure, but it's not. The addition of a crossover makes it a fifth order system."

how efficient is this box design? i will will be running a crossover. that will make it a 5th order, right? it will be tuned @ 33 Hz. and what if i were to port the out side chambers in to the center chamber? what would it be then? a three chamber Quasi Sixth Order Series-Tuned Bandpass? or would it just be a bad idea? @ first my designer was going to do a 4th order series-tuned type of box. then he told me the Three Chamber Single Reflex Bandpass set up would best for my application, and would not need as much "tweaking" as the series tuned 4th order would. what do think? any intelligent input would be greatly appreciated!!

thank you for your time!!!

metaljoey · 09-23-2010

should i type slower so someone will understand? lol

fosg8freak · 09-23-2010

i dont think many of us know about this type of enclosure. Maybe pictures will help?

metaljoey · 09-23-2010

Car Audio subwoofer Enclosures Fourth Order/Bass Reflex and Bandpass

dustin420 · 09-23-2010

looks like a simple 4th order just using a lot of subs. might wanna talk to fallen or go to hexibase forum and talk to pete.

sri3850341 · 09-23-2010

those are 4rth orders.. if you where to port the sealed side it then would be a 6th order.. 6th order is more forgiving to a larger selection of subs whereas a 4rth order is more sensitive to design and driver selection..

RidinLoudProd · 09-23-2010

Yeah if i was you. Id have fallen design it for you specifically for your subs. you can go to Nightmare Audio to get more information on him and send a request forum for the box.

metaljoey · 09-23-2010

this is what i got on 6th & 8th orders.
Most often only seen in SPL competitions, the sixth & eigth order bandpass and Quasi-sixth & Quasi-eighth order bandpass enclosures can offer a GREAT deal of SPL in a "relatively" small enclosure if built "dead on balls accurate", but often (expletive removed) at reproducing anything worth listening to in the mobile enviroment. Unless precisely constructed, the end result is almost guaranteed to be a waist of time, money, and effort.

Don't let my opinions stop you from trying. Remember, it doesn't matter what I like or for that matter what anyone else likes. It only matters what you like. So if you're feeling ambitious, and want something that has the potential of being incredibly loud, go for it, but keep the following in mind and please do not email me if you waist a few hundred dollars or more on lumber, hardware, and replacing blown woofers. The only response you'll get from me is "I told you so." Enough of my rambling (heh). Here's what you should know.

The enclosure's performance is limited to a very narrow bandwidth of frequency response and can be extremely complex to build correctly. Woofers are very susceptible to cone over-excursion for frequencies outside of their operating region (specifically when they unload below the tuned port frequency). For this reason alone a high quality electronic crossover should be used with a 24 dB per octave cut-off slope or higher and each woofer should be fused appropriately.

It is unlikely that you will be able to hear when a woofer in these enclosures is about to turn into a paper weight, but once you do notice it, it's probably too late. And now if you haven't made the enclosure so it's easy to change the woofer, you're probably wishing that you never decided to build it in the first place.

The transient response of a sixth order enclosure is worse than any other enclosure with the exception of an eighth order enclosure. The power handling is excellent within the bandpass region and SPL can be intense. This is what makes these a great choice for some SPL competitors, but for everyday listening, they are less than desirable.

So why did I make this page about sixth and eight order enclosures? Mainly so you can recognize these enclosures and perhaps if you happen to see any in use, you'll have some appreciation for the effort that went in to the design and construction of them. I take my hat off to those that have done it correctly, but as you can tell, these are not enclosures that I feel are worth trying to incorporate into a mobile enviroment. For the amount of space, time, money, and effort it takes to build any of these enclosures, you can more easily build enclosures that are more suitable for everyday listening and that can be just as competitive.

metaljoey · 09-23-2010

i got the plans layed out with the help of DD9915D!!!. he's the master mind on this build!

dustin420 · 09-23-2010

8th oder bp? o sh1t, you know how hard thats gonna be to design and you better hope everything comes out perfect witht he build cuz one little 1/16 off will fvck up everything.

sri3850341 · 09-23-2010

i have a question, why?

xseveredveganx · 09-23-2010

Quote:

Originally Posted by sri3850341

i have a question, why?

Exactly. Why do you want to design and/or construct an 8th order bandpass? Is it because it looks difficult or is it because the driver that you are trying to build for has suitable paramaters for this particular alignment?

I'm assuming it's because it looks difficult...

metaljoey · 09-23-2010

the plan for the box is to do a Three Chamber Single Reflex Bandpass. not a 6th or 8th order. i would be down for a simple ported box or two. this is what i got from fallen;

"a 4th order bandpass isn’t very efficient if the passband is large. IF it has the same passband as a sealed box(it’ port length approaches 0 or port area approaches infinity, and the volume of the ported chamber approaches 0) then it’s output will be identical. The gain it gets over a sealed box is by sacrificing bandwidth. So if you don’t need to play above say 70Hz with the sub, then converting that bandwidth can net us some gain.

So that said, ported boxes have 3dB across the board, since they use both waves. But roll off at a much more rapid rate. It takes a huge sacrifice in bandwidth for a 4th order to be more efficient than a ported box.

I hope that helps a bit.

-Jud

BTW 4th order bandpasses aren’t series or parallel tuned per se as one chamber never vents."

i will probably get with my designer and see what other opticians are available.
i don't have too much room with 4-12" going in a trunk.

profundus-sanus · 09-24-2010

honestly i doubt you have the room for 4 12's in a 4th order in a trunk

your looking @ at least 12 cubes net... probably 15-18 total

profundus-sanus · 09-24-2010

also... i dont' agree with fallen at all in what you quoted..

a porperly designed 4th order can beat or at least match the output of sealed at all frequencies. the narrower passband to gain is just that.. you may only have more output than sealed from say 30-60hz or however it may be designed.

edit: i suppose i could see a loss in output at extremely low frequencies due to the restriction from port area.

Capwn · 09-24-2010

Quote:

Originally Posted by ridinloudprod

yeah if i was you. Id have fallen design it for you specifically for your subs. You can go to nightmare audio to get more information on him and send a request forum for the box.

qft.

metaljoey · 09-26-2010

i would like it to be louder than a sealed box. i was unsure about this design. I'm not quite sure what I'm gunna do yet. i would like to utilize 4-12", if i can.....

sri3850341 · 09-26-2010

a simple proper/ported design will probably meet your expectations...

metaljoey · 09-27-2010

thats what i want. nothing all crazy. might look@ doing 3-12" in a good old ported box! with a tune around 32 Hz er so. i think i will be able to give them the proper space they need.
3 dvc 4 ohm subs in parallel will be .6666 ohm. that don't sound to bad.

Fallen · 10-04-2010

Quote:

Originally Posted by profundus-sanus

also... i dont' agree with fallen at all in what you quoted..

a porperly designed 4th order can beat or at least match the output of sealed at all frequencies. the narrower passband to gain is just that.. you may only have more output than sealed from say 30-60hz or however it may be designed.

edit: i suppose i could see a loss in output at extremely low frequencies due to the restriction from port area.

Profundus that is what I am saying.

I'm saying if the sealed chamber is the same as a sealed box, and the vented chamber is tuned very high(approaching infinity, way out of the band we'll play) it'll have the same performance as a sealed box. But as we add length to the port we bring the tuning down and start sacrificing some bandwidth for gain. Once that tuning gets below 60Hz then we really start gaining over sealed. All I'm trying to say is a 4th order bandpass is a sealed box with an acoustic low pass filter. It's a second order high pass due to the sealed box and a second order acoustic low pass, which nets us a 4th order bandpass. I completely agree with you

metaljoey · 10-05-2010

the tuning will be at 32 HZ. if this helps........

Fallen · 10-05-2010

That is pretty low for a 4th order bandpass...(unless that's the sealed chambers tuning)

RyanM923 · 10-05-2010

Quote:

Originally Posted by Fallen

That is pretty low for a 4th order bandpass...(unless that's the sealed chambers tuning)

x2, I assume he's talking about a new ported box idea?

Fallen · 10-05-2010

I sure hope so...
because efficiency goes out the window if your ports tuned lower than the frc lol.
Essentially like putting a muffler on the sub lol.

metaljoey · 10-07-2010

no, its the bandpass. idk what the sealed chamber tuning is. i was told the port will be tuned for 33HZ. sounds like this wont work very well? it will be going down soon. and it will be built inside the trunk. so i would like it to be right! any suggestions? im being told not to worry about it. and this is the way to go. he knows his sh!t, i am just unfamiliar with this type of enclosure.