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To bandpass or not to Bandpass


bigmacjack

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I am going to be building my first spl vehicle, and the guy i work with is suggesting that i build a 6th order. now i have looked online and have asked around a little bit but i wanted to get a few more opinions on the matter. originally i was just gonna build a high tuned aeroport box but he is claiming i should get +12db from using a bandpass? now i would have thought that if this was true every person would be doing bandpass. can anyone shed a little light on this situation for me?

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Talk to @the_garynator and @Triticum Agricolam. There may be others with experience in 6th orders on the forum, but those are the only two that stand out to me that have posted much about them

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I would stay away from any builder that says they can get 12+ db's from a specific enclosure type over another. Its just not happening, even if said person built 1 loud vehicle that is the same as yours and using all the same gear does not come close to equaling the same score.

Look at Honda CRX's as a perfect example, one of the loudes vehicles in the Street Stock competition classes, and proven over and over again that no 2 CRXs are the same in terms of loudness (even if you take 1 setup out of one and put it in another with the vehicles year, model, and options all being the same)...

Not to mention that a 6th order is one of the more challenging enclosures.

There is no get a design, build it, and the out come being the loudest it can be.

You will have to test, alter, and tune over and over and over again.

Not only do you have 2 ports that you will have to adjust the tuning too, but also the port area, and chamber sizes.

 

 

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i was building this to do burps and maybe some music just for fun at a comp. thats one of the main reasons i didnt wanna do one is the amount of testing and tweaking it would take not to mention i have never built a 6th order before. i thought it was pretty ridiculous for this guy to promise me 12 db gain 

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I could probably help you design a series tuned 6th that would be pretty good without any messing around, but it would require fairly precise building / assembly. Also, to answer one of your questions from earlier, the reason you don't see a ton is due to a few reasons.

  1. Most people don't understand 6th orders
  2. Most people tend to test and tune, which requires vastly more work when dealing with a 6th than a standard ported box
  3. 6th orders require a lot more space than ported boxes
  4. 6ths are more complex to design and build than ported
  5. 6ths are a lot less "forgiving" than ported boxes, even slightly miscalculations / mistakes can not only cause poor performance but equipment failure. Similar to 4th orders, the "front" high tuned chamber acts as an acoustic filter which filters out high frequencies, this paired with the fact that in a lot of cases you can't see the woofers' excursion means if they are bottoming out, you won't be able to hear it and you have less of a chance to see it. 
  6. 6ths, especially the large ratio ones built for large subs, tend to have extremely high impedance rise. For example, I saw 6x rise 3hz below the tuning frequency of my low tuned chamber in my parallel 6th order walk through with 2 sundown x15s. They were wired to 1ohm per channel on my warhorse and rising to 6ohm per channel!  
  7. Bandpass enclosures, especially the larger ratio ones where you'll see the biggest gains over a standard alignment can be pretty hard on the suspension of the subs.

With all of these 'cons' you may be wondering why anyone even bothers with them. Most people don't, hence why you see mostly ported lol.  But the answer is, properly built / designed / planned, they can be quite incredible. You can get all of the spl a ported box has with a substantially larger bandwidth, or quite a large bump in output if built for spl.

An example of bandwidth are the parallel 6th orders I built a few years back for my roadmaster wagon. The second one was for 2 alpine type r 10s. Running 2 apsm2000s strapped, they did high 130s to low 140s sealed at the dash from 29hz all the way to 70hz in a vehicle that metered absolutely terrible no matter what was donever short of walling it. For comparison, we put them in the back of my friend's 4runner and ran the speaker wire to my car and they did a 149 at 36hz sealed at the dash, car off.  They took 2x rms (clamped) daily and 3x for burps!

On the spl side, my series tuned 6th order blow through in my hardbody pickup did 150.2 sealed at the dash with 2 12" power acoustiks mofos  (the crappy 2.5" coil ones) on a shark 3500 clamping under 2000wrms AND did hair tricks!  The bandwidth wasnt anything to write home about though, being a huge ratio and tuned low. Was close to a 5:1 ratio.

Hope this was informative.  Let me know if I can answer any questions or help.

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53 minutes ago, the_garynator said:

I could probably help you design a series tuned 6th that would be pretty good without any messing around, but it would require fairly precise building / assembly. Also, to answer one of your questions from earlier, the reason you don't see a ton is due to a few reasons.

  1. Most people don't understand 6th orders
  2. Most people tend to test and tune, which requires vastly more work when dealing with a 6th than a standard ported box
  3. 6th orders require a lot more space than ported boxes
  4. 6ths are more complex to design and build than ported
  5. 6ths are a lot less "forgiving" than ported boxes, even slightly miscalculations / mistakes can not only cause poor performance but equipment failure. Similar to 4th orders, the "front" high tuned chamber acts as an acoustic filter which filters out high frequencies, this paired with the fact that in a lot of cases you can't see the woofers' excursion means if they are bottoming out, you won't be able to hear it and you have less of a chance to see it. 
  6. 6ths, especially the large ratio ones built for large subs, tend to have extremely high impedance rise. For example, I saw 6x rise 3hz below the tuning frequency of my low tuned chamber in my parallel 6th order walk through with 2 sundown x15s. They were wired to 1ohm per channel on my warhorse and rising to 6ohm per channel!  
  7. Bandpass enclosures, especially the larger ratio ones where you'll see the biggest gains over a standard alignment can be pretty hard on the suspension of the subs.

With all of these 'cons' you may be wondering why anyone even bothers with them. Most people don't, hence why you see mostly ported lol.  But the answer is, properly built / designed / planned, they can be quite incredible. You can get all of the spl a ported box has with a substantially larger bandwidth, or quite a large bump in output if built for spl.

An example of bandwidth are the parallel 6th orders I built a few years back for my roadmaster wagon. The second one was for 2 alpine type r 10s. Running 2 apsm2000s strapped, they did high 130s to low 140s sealed at the dash from 29hz all the way to 70hz in a vehicle that metered absolutely terrible no matter what was donever short of walling it. For comparison, we put them in the back of my friend's 4runner and ran the speaker wire to my car and they did a 149 at 36hz sealed at the dash, car off.  They took 2x rms (clamped) daily and 3x for burps!

On the spl side, my series tuned 6th order blow through in my hardbody pickup did 150.2 sealed at the dash with 2 12" power acoustiks mofos  (the crappy 2.5" coil ones) on a shark 3500 clamping under 2000wrms AND did hair tricks!  The bandwidth wasnt anything to write home about though, being a huge ratio and tuned low. Was close to a 5:1 ratio.

Hope this was informative.  Let me know if I can answer any questions or help.

thanks for all the info! i really really appreciate your willingness to share your knowledge with me and help me out. but i think its a little beyond my skill level at the moment. i would like to eventually try one and ill defiantly be coming to you with questions lol. so again thank you!

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I run a series tuned 6th for 2 18s....currently have Zv4s in at the moment and I've played with the rear port twice and front port about 5 times (shrinking and making larger) just to get where I'm happy with it.So like others have said it takes work but can be done...space wise can not be sacrificed what so ever...mine is about 35 cubes total net for 2 18s but have a bandwidth from 15hz-about 65ish hz....does a 155 sealed on the Dash at 29hz and a 154.2 sealed on the dash at 52hz which is my upper peak...from 20hz-57hz it'll do a 151+ sealed with the strongest bandwidth from 25-55(does a 154+ sealed) crack the driver window and it becomes a different beast and some of the peaks change will do a 156.7 on the dash window down and a 156.4 in the head rest all at 33hz.a 158.2 in the kick at the same frequency if that's your sort of thing...mostly the low frequencies pick up with the window down does a 153 at 20hz window down and a 155 at 25hz....sorry for the rambling but what I'm getting at is it took about a year and some playing with some things to get it to this point,so if you like testing and tuning and have the space I say go for it......p.s if I shrunk the rear chamber to get the rear port tuning as close to the front chamber tuning as possible I've gotten a 159.1 at 45hz sealed on the dash but only has a usable bandwidth of about 3hz MAX before woofers look like they'll jump out of the box 

2000 Suburban 6 runs of 2/0

12 timpano audio mids,6 timpana audio tweets and 1 timpano compression horn per door 

8 banks of blue Maxwells + 260ah of Yin Long LTOs 

2 370 Amp Autotech Alts 

mids amps 2  Crescendo Skyway 3ks 

Tweet amp Crossfire 2000.4

sub amp: 4 Crossfire XT 8ks

Subs: 8 18 in Crossfires in a 4th order


Best Scores at events…

161.6@38hz DBdrag  sealed on the dash… 162.54 outlaw…161.14 Meca headrest 

 

 

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