4th order isobaric bandpass enclosure - Audio & Electronics Forum

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4th order isobaric bandpass enclosure
Monday, July 11, 2011 5:06 PM
alright boys and girls
let's see if somebody on here actually knows car audio
here's the deal. i am in the process of building more efficient box with better transience response that can dip into lows better.
the problem with ported box is that the peak db levels are 10-15 hz higher than the tuning area and while tuning lower would resolve the issue i am loosing a lot of output as a result, plus i loose a lot of tightness with it. so ported box does not really work for me anymore
now, i'm thinking about either building a 4th order isobaric bandpass enclosure OR 3 chamber single reflex 4th order bandpass enclosure
my question is there really a difference between the 2? also when it comes to those types of enclosures i know that the sealed portion of enclosure stays the same in volume but what about the ported area? does it receiver the same volume as well but with double the port area? or can i go double the volume with the same port area?

Re: 4th order isobaric bandpass enclosure
Monday, July 11, 2011 5:12 PM
kind hard to design an enclosure without knowing the equipment your using, down to the T, links and all. and dont waste your time with a 4th order, do a good ported and youll be happy. ive gotten flat response from 30-46 (within .5 db) with just standard slot...




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Re: 4th order isobaric bandpass enclosure
Monday, July 11, 2011 5:55 PM
what are your peak gains between 30-50 hz??
right now i am running a pair of 12 p3s with rf t1000 amp. tuned to 36 hz and even though i am tuned at 36 my gain is at 4.88 at 45 hz, f3 is at 30hz!!
i could extend the port another 10 inches and tuned it to around 32 but then my output would be something like +3db at about 40 hz with f3 at around 28hz
i take it rf subs are more spl than sq...
Re: 4th order isobaric bandpass enclosure
Monday, July 11, 2011 6:31 PM
you need to step away from the box program.... lmao

NONE of those number mean anything once you get it in the car....




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Re: 4th order isobaric bandpass enclosure
Monday, July 11, 2011 6:44 PM
box program has nothing to do with this
what i am saying is with the box being tuned at 36 hz it still sounds boomy and doesn't catch lows as well and i am not happy
Re: 4th order isobaric bandpass enclosure
Monday, July 11, 2011 7:00 PM
wrong equipment, install, tuning, operator? There are a TON of other factors. And I would like to agree that doing a 4th order is going to be a huge waste of wood, space and time dude.


(tabs) wrote:
z yaaaa wrote:its not much fun trying to argue with a wall.
oh, trust us, we know

Re: 4th order isobaric bandpass enclosure
Monday, July 11, 2011 7:00 PM
anybody on here actually built 4th 6th or 8th order bandpass or just like anton here express their enthusiasm of what it might sound like without much clue how to build one..
Re: 4th order isobaric bandpass enclosure
Monday, July 11, 2011 7:42 PM
Built one? Nope. I don't do wood work, I outsource it to someone with far more skill and experience than me. Heard, seen, know about? Yes.


(tabs) wrote:
z yaaaa wrote:its not much fun trying to argue with a wall.
oh, trust us, we know

Re: 4th order isobaric bandpass enclosure
Monday, July 11, 2011 8:06 PM
I've built a 6th order and I've encountered their physical properties at school a lot. Fact is, you won't get good transient response out of a 6th.

If you want to get low frequency extension AND SPL get power, get cone, and cross over low.



Re: 4th order isobaric bandpass enclosure
Monday, July 11, 2011 8:09 PM
^in a sealed box the size of your house. Of course.



Re: 4th order isobaric bandpass enclosure
Monday, July 11, 2011 8:55 PM
what about 4th or 8th? i am not looking for spl..
what i am looking for is flat response from 30 to about 50hz with good transient response.

Re: 4th order isobaric bandpass enclosure
Monday, July 11, 2011 9:00 PM
The thing about 2nd (ported), 4th, 6th and 8th order bandpass boxes is that they exploit harmonics, and harmonics in air are subject to drag which = poor transient response.
I am, and I think I always be biased toward sealed, ESPECIALLY for low frequency.

You say it's boomy. Where is your crossover set?



Re: 4th order isobaric bandpass enclosure
Monday, July 11, 2011 9:08 PM
i've had sealed and i've had ported boxes all built professionally and to manufacturer's specs
and i am not impressed with either. sealed boxes really don't catch lows at all, (i've built it slightly bigger with higher Qtc and still no luck)
pretty much same with ported. i build it and tuned it to 36 hz and yet it pounds out mostly in 50s, and it doesn't sound good
i been playing with crossover for a long time now, and found it working best at 60 hz
don't get me wrong, it still sounds decent, and it's LOUD as hell, but it sucks big time when it comes to SQ
Re: 4th order isobaric bandpass enclosure
Tuesday, July 12, 2011 4:26 AM
umm the sub your using has allot to do with playing low. my 10" idq sealed box was designed so my 3db down point was around 14hz.. if your using spl subs to try and get sq your likely going to not get low because its easier to hit a high spl with 50hz then it is to do it at 30 hz. i can point out so many world sq champions who use sealed and ported boxes and are very very accurate. and you don't want a flat responce from any speaker, flat responces actually sound bad. what you want to try and attain is a smooth responce.

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Re: 4th order isobaric bandpass enclosure
Tuesday, July 12, 2011 6:45 AM
Andrey B wrote:box program has nothing to do with this
what i am saying is with the box being tuned at 36 hz it still sounds boomy and doesn't catch lows as well and i am not happy




YOU NEVER SAID WHAT EQUIPT YOU WERE USING EITHER...




click sig for my car audio videos
Re: 4th order isobaric bandpass enclosure
Tuesday, July 12, 2011 8:13 AM
Anton Miller (PPC) wrote:
Andrey B wrote:box program has nothing to do with this
what i am saying is with the box being tuned at 36 hz it still sounds boomy and doesn't catch lows as well and i am not happy




YOU NEVER SAID WHAT EQUIPT YOU WERE USING EITHER...


yes i did
Re: 4th order isobaric bandpass enclosure
Tuesday, July 12, 2011 11:11 AM
Yes he did. He said he's looking for great low end extension and sound quality out of rf p3's........


(tabs) wrote:
z yaaaa wrote:its not much fun trying to argue with a wall.
oh, trust us, we know

Re: 4th order isobaric bandpass enclosure
Tuesday, July 12, 2011 11:46 AM
Maybe a t-line?



Re: 4th order isobaric bandpass enclosure
Tuesday, July 12, 2011 11:47 AM
what's wrong with p3s?
i compared them with SAs and they were oh so similar spec wise, can't complain about quality finish either.
i realize that it's not the best sub for SQ out there, but just didn't think it would sound this bad.. i guess i should've tuned it lower to like 30 hz or something, but i get the feeling it wouldn't change things much..
Re: 4th order isobaric bandpass enclosure
Tuesday, July 12, 2011 1:06 PM
If you are 100 percent confident that the install, box fabrication, box dimensions, and amp/eq/crossover tuning are perfect, there's either an equipment issue or you did something wrong. You seem to think that because your particular setup doesn't sound exactly how you want, its the type of box. I think there are other factors such as box design, build, or tuning. As jason said, I've also seen sealed and ported boxes do everything you seem to want. There's another factor, period.


(tabs) wrote:
z yaaaa wrote:its not much fun trying to argue with a wall.
oh, trust us, we know

Re: 4th order isobaric bandpass enclosure
Tuesday, July 12, 2011 1:27 PM
Can you post up a picture of the box please?




Re: 4th order isobaric bandpass enclosure
Tuesday, July 12, 2011 1:41 PM
JLAudioCavalier wrote:Yes he did. He said he's looking for great low end extension and sound quality out of rf p3's........


why am i not seeing the info about what subwwoofers/amps and such that hes using?




click sig for my car audio videos
Re: 4th order isobaric bandpass enclosure
Tuesday, July 12, 2011 1:41 PM
third post



Re: 4th order isobaric bandpass enclosure
Tuesday, July 12, 2011 2:04 PM
This is the guy who said you had to remove the entire dash to change the gauge cluster.


- Your not-so-local, untrained, uncertified, backyard mechanic. But my @!#$ runs
Re: 4th order isobaric bandpass enclosure
Tuesday, July 12, 2011 2:08 PM

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