lone blazer
hey guys, so heres what i got and im trying to design a bandpass enclosure (lower tuning) since they are new to me , but i need some help.

2001 S-10 single cab w/ cut thru just below the window.
4 15 inch FI ssd's
2 soundstream rubicon 2500d's
about 17 cu. ft. of box space

now the questions i have are;
whats a proper way to decide a ratio for my enclosure? (i've heard all different combinations)

how do i make a bandpass play decently low? (everytime i use winisd it seems like i cant get a decent f3 rolloff at no less than 40, and the same with impedance)

what affect does the cabin have on the enclosure since my cab is extremely small.
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lone blazer
forgot to mention i was thinkin 4th order
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Goldtaz1
If I were you, I would shoot for 1.5-1.75 cubes net sealed per 15. Use 2.5-3:1 ratio for the ported chamber and 20-25 square inches of port per cube tuned to 45-47 Hz. This should definitely get down like no one's business.
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lone blazer
my problem is according winisd my cutoff range drops like a rock at 40hz. i hear that bandpass setups like to get really low but from what i can tell its not going to at all. is there something im missing? i know theres cabin gain and all but that doesnt seem near enough to make up for like 20db rolloff
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Goldtaz1
Winisd is a prediction of rolloff at best. My brother had an extended cab s-10 with 2 type r 12's in a ported enclosure that got plenty low. I would not take as much stock in a program as you are trying to. If it's designed properly and built properly, you should not have any problems at all playing low and doing well on the meter.
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lone blazer
i have faith in what you preach. im just weary because this will be my first bandpass. I have had a hand in many 150+ vehicles but they were all ported. so this is pretty different. plus i have only one shot at getting the box right because i have to build it into the bed and cab, and its going to be pretty hard to make changes since its only 16 inches tall lol i guess i just need some reassurance im going in the right direction.
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Goldtaz1
If I were you I would shout at GalaticMonkey, iamamp3pimp, or 80inches about bandpass enclosures. Those guys have a great deal of experience with bandpass designs/implementations. You may be more successful at contacting them over on the floridaspl.com forums. I've done a handful of bandpasses now at the direction of galaticmonkey and he has yet to steer me wrong. There is also a lot of technical reading on the floridaspl.com forums about bandpass theory/design that you should check out.
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lone blazer
would the subs be better off in their own seperate chambers or would it help the airspace "feel" bigger if i had 2 in their own common chamber on each side? they will be within a couple inches of each other.
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lone blazer
cool thanks
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Goldtaz1
Quote:
Originally posted by lone blazer:
would the subs be better off in their own seperate chambers or would it help the airspace "feel" bigger if i had 2 in their own common chamber on each side? they will be within a couple inches of each other.
That is definitely a good question and I would certainly love to know the answer as well. I know in all of the bandpass boxes I've done and most of the ones I've seen done on the forums, they utilize a shared sealed chamber. If someone provides a reason why one way is better than the other, please update this thread.

Brandon
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2doorcavy
getting very close to starting this build!
if anyone has or knows someone in the ohio/P.A. area that has a cap for a s10 it could make this project start up a lot quicker and make it much more easier : )
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winslow
You also have to realize you are working with the transfer function of the car too. A rear tuning of 40ish would match the inverse of the transfer function. Basically you will be getting 20 or more dB of free gain at 20 hertz and decreasing to somewhere near 45-50 hertz.

Common chamber is easier to build and would be easier for a large bandpass since the shared airspace will be equally divided between the speakers. Separate chambers could have small changes in size and volume creating tuning variances between each chamber...which you don't want. Granted they will be small and probably not of any real importance...but if you don't have to worry about it, then why worry about it?
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80INCHES
bandpass ftw!!!!!!!!!!
but to stay on topic..17cubes i dont think its enuff for 4 15's in a bandpass...if u have another 6 cubes internal then yea i would say go for it
80
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galacticmonkey
Yeah, its a little small, but if thats what you have your heart set on, you can make it work.

Id do a box with a V with 2 subs on each side. Make each side 4 cubes (2 cubes per sub). Usually you can get away with smaller, but since the SSDs dont have much motor force, you need a bigger sealed chamber to let them move easier. This will help them play lower and cool better because of the excursion. After that, take whatever the ported chamber is, and go for around 20in^ of port per cube of ported area, after all displacements. Tune to around 45hz, and it should kill some lows.

I had 2 Ascendant Chaos 18s (Basically SSDs) in a 4th order blowthrough in my Avalanche. They were in 2.1 cubes sealed each, firing into like 18.5ish cubes ported. 400in^ of port @ 39hz. Didnt play as low as I wanted, but had awesome ouput from about 28hz-90hz. Subs did get stinky if I wasnt careful because at full tilt with 1500w on each they would move maybe 1/4" each on any note. They just didnt have the motor force to move the coil far enough to cool themselves.

One thing that I would suggest is putting the magnets in the ported chamber to help with airflow around the coils. This will also let you smell them if they do heat up.
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