15" sub bandpass box

[scottyfkachris 10+ year member]

This is my plans for a bandpass enclosure for a 15" crossfire bmf the sealed portion is 2 cu ft. and the ported part is 3.3 cu ft but i dont know how to figure out the port. the sub calls for a 2 cu ft. sealed enclosure and a 3.15 cu ft ported enclosure. so i figured taking out the port and supports on the ported side it would even out to about 3.15 cu ft. Im using 3/4 in mdf. I dont know whether i want to do a port going into the cabin or facing the cabin or facing the trunk. Im thinking about doing it into the cabin and doing an amp rack behind it. its going into a ford zx2. I dont know how to figure out the size of the port. I was thinkin either using a side for length but I might do cylinder ports into the cabin. Which would sound better square ports or cylinder ports?? Im going for SQ and not so much spl. I was thinking of tuning the box to 30 hz.

any help appreciated.

P.S. anyone know of any good box building programs?? Im still using the old school pen, paper, and math skills. //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

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[80INCHES 5,000+ posts]

do 3.5 cubes sealed 1.8ported

and tune ur ported chamber to 50hz

80

 

[scottyfkachris 10+ year member]

why should the sealed be bigger and the ported be smaller?? and wouldnt 50 be too test tone style?? it is my daily driver and how do you figure out the port size dimensions?

 

[406er 10+ year member]

you dont know that much about bandpass do ya. also what strikes me as odd is that your goin for SQ and not SPL, wich 90% of bandpass are for SPL aplications. also taking the subs ported and sealed recomended enclosure volumes and putting them together dosnt make it the ideal band pass enclosre volumes. my advice for you is build a seald box or a low tuned ported box for MAX SQ

 

[galacticmonkey 5,000+ posts]

4th Orders can sound sick if done right.

80s design should play REAL smooth.

 

[80INCHES 5,000+ posts]

4th Orders can sound sick if done right.
80s design should play REAL smooth.

BINGO!!!!!!!!!!

u knew exactly wat i was talking about!!!!

//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

why should the sealed be bigger and the ported be smaller?? and wouldnt 50 be too test tone style?? it is my daily driver and how do you figure out the port size dimensions?

you dont know that much about bandpass do ya. also what strikes me as odd is that your goin for SQ and not SPL, wich 90% of bandpass are for SPL aplications. also taking the subs ported and sealed recomended enclosure volumes and putting them together dosnt make it the ideal band pass enclosre volumes. my advice for you is build a seald box or a low tuned ported box for MAX SQ

he wanted something that was more sq not so much spl....thats why i said make the sealed chamber bigger ..and the ported chamber smaller...the bigger the ported chamber the peaker it will be....the smaller the ported chamber the more flat it will play and with a bigger sealed chamber the lows will be really nice...remember 4th order bandpass have the same characteristics as a sealed box the transent response will be very similar..if done right

80

 

[scottyfkachris 10+ year member]

Ya this is my first bandpass enclosure im trying. ive done a couple sealed boxes and one ported box in the past. thanks for all the help. i guessed that the sealed and ported rec. would be the deminsions needed but ill try and figure out the design 80 gave. im still tryin to figure out port deminsions tho. Thanks for the help 80

 

[scottyfkachris 10+ year member]

im still lost in trying to figure out the port size deminsions. Im going to try 3.5 sealed and 1.8 ported tuned to 50hz like 80's design. I want to use one or 2 3" pieces of pvc pipe or maybe just one bigger one. Can anyone help me figure out what the port length should be or know of any program that could help me out on this box?

 

[80INCHES 5,000+ posts]

use 4 3inch round ports each at 14inches long

80

 

[DNick454 10+ year member]

BINGO!!!!!!!!!!u knew exactly wat i was talking about!!!!

//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

he wanted something that was more sq not so much spl....thats why i said make the sealed chamber bigger ..and the ported chamber smaller...the bigger the ported chamber the peaker it will be....the smaller the ported chamber the more flat it will play and with a bigger sealed chamber the lows will be really nice...remember 4th order bandpass have the same characteristics as a sealed box the transent response will be very similar..if done right

80

Having the bigger sealed chamber is better for making a flatter response, so listen to 80. If you truly want a bandpass for SQ purposes, that would be a great setup. The nice big sealed chamber will give it great response and woofer cone control down to any frequency and the small ported chamber will keep the bass tight and not sloppy so it should do really well for SQ purposes and still get hella loud.

 

[scottyfkachris 10+ year member]

alright thanks guys. ill be starting to build the box either today or tomarrow.

 

[scottyfkachris 10+ year member]

heres my new design thanks to the help of 80 for the internal airspace and port demensions.

what you think?

 

[dappa5 10+ year member]

before you build that box STOP! download sketchup and present a proper drawing lol just playin' gl w/build

 

[Fuknmovin 10+ year member]

Whatever you do.....MAKE SURE you LISTEN to 80, he knows his CHIT! I LOVE my 6th order he designed for me!!!!

 

[scottyfkachris 10+ year member]

box is gonna have to be put on hold. did some more measurements and it is going to have to be permanently built into my trunk. So im gonna wait until i have everything done for the set up. BUT be looking for a build log in a month or so. Thanks for all the help!