Port area FI BL's

[KenC210 3]

So i am just curious what is a good port area for 2 fl bl 15's

[Kangaroux 47]

Depends what you're tuning to, the kinda music you like, power, etc.

[KenC210 3]

normal rap or hip hop sometimes dubstep rock classic rock country... a lot of different types music of music. I was thinking of tuning around 32-34hz

[Quentin Jarrell 671]

dv = 39.37 (fb x Vd)^1/2

dv= minimum port diameter of vent in inches

fb= box tuninf frequency in hertz

vd= cone displacement in cubic meters (one way xmax in meters times cone area in meters)

[95Honda 486]

I just hope everyone takes note that enclosure volume is not in your equation.

Thank you for actually posting something usefull and objective about this question that comes up about every day...

[Quentin Jarrell 671]

I just hope everyone takes note that enclosure volume is not in your equation.

Thank you for actually posting something usefull and objective about this question that comes up about every day...

It won't matter because the people with 4 15's with only 200 inches of port cramed in a wall in a 4 door sedan will run their head about not hear any port noise. But you and I know the differance between hearing port noise and the correlation between port COMPRESSION and decreased spl, increased coil temperatures, and higher group delays.

It just blows my mind that people spends thousands and thousands of dollars on equipment and won't spend 40 bucks on a book to learn how to apply the equipment.

[KenC210 3]

I just hope everyone takes note that enclosure volume is not in your equation.

Thank you for actually posting something usefull and objective about this question that comes up about every day...

Not to sure how your coming off but according to the features straight from the site to buy them it suggest a 3-5cubic feet as per sub. So one could only assume 6-10cubic feet. Anyone with experience with the fi bl 15's would have a good suggestion on a port area. So i guess to be a little more clear i am going to stay within the 6-10cuft. It also is going to be in a daily driver not for spl application so i would like it to sound good

[Duran 387]

Well said Quentin, well said.

[KenC210 3]

never mind i found it... thank you

[KenC210 3]

Alright so could someone check these specs.

I have right now

width 41

height 22

depth 20

Port

height 20.5

width 4.75

length 31

I am getting just over 32hz for tuning and my port area im getting 97.375. After the the displacement i am just over 6cuft.

Edited September 30, 2012 by KenC210

[Shogen 325]

http://portsgalore.stefanhinote.com/?do=portarea

try that link out...

[Quentin Jarrell 671]

Back to Small's formula formula

dv = 39.37 (fb x Vd)^1/2

dv= minimum port diameter of vent in inches

fb= box tuninf frequency in hertz

vd= cone displacement in cubic meters (one way xmax in meters times cone area in meters)

for one BL 15

xmax= .018 meters

sd= .018 meters^2

tuning= 32 hertz (per you)

dv= 39.37 (32 x .018 x .081) ^1/2

dv= 39.37 (.046656)^1/2

dv= 39.37 (.216)

dv=8.5 inch diameter port per sub

dv=56.72 square inches

for two 15's you need (2)dv. So you need 113.44 square inches of port

[ImBob 2]

I just hope everyone takes note that enclosure volume is not in your equation.

Thank you for actually posting something usefull and objective about this question that comes up about every day...

It won't matter because the people with 4 15's with only 200 inches of port cramed in a wall in a 4 door sedan will run their head about not hear any port noise. But you and I know the differance between hearing port noise and the correlation between port COMPRESSION and decreased spl, increased coil temperatures, and higher group delays.

It just blows my mind that people spends thousands and thousands of dollars on equipment and won't spend 40 bucks on a book to learn how to apply the equipment.

Random noob entering the thread to try to explain the ignorance of a noob. I've read a bit lately about port area for subs, and if you are a complete noob, the info can be confusing (and/or just straight up contradictory). First you have to determine what info and from where seems trustworthy, and there's several reasons why that first step alone can be very frustrating.

Next you may read the same thing over and over again, like this example - 12-16 in^2 of port area per foot. But after lots of searching and just when you think you know enough, you may find one obscure post saying something like "port area has nothing to do with box volume"...wait, what?!?! It's not just 12-16 in^2 per ft??? Not only did I (and I'm sure many others) read that on many forums before I started searching here, I also read it in a sticky here :

BL 15 – Ported box we recommend using 2.8-4 cubic feet @ 28-37Hz. Again use 12-16 square inches of vent area per cubic foot of volume.

Most people probably don't know of that $40 book or even just the need for it, and maybe some knowing of it would think these types of forums would be ample Cliffs Notes for it. Ok so I guess I'm done rambling, just wanted to explain the frustrations some of the noobs have in trying to "get it right".

Thanks to all who are spreading good info!

Edited October 2, 2012 by ImBob

[EPerez 236]

I just hope everyone takes note that enclosure volume is not in your equation.

Thank you for actually posting something usefull and objective about this question that comes up about every day...

It won't matter because the people with 4 15's with only 200 inches of port cramed in a wall in a 4 door sedan will run their head about not hear any port noise. But you and I know the differance between hearing port noise and the correlation between port COMPRESSION and decreased spl, increased coil temperatures, and higher group delays.

It just blows my mind that people spends thousands and thousands of dollars on equipment and won't spend 40 bucks on a book to learn how to apply the equipment.

Random noob entering the thread to try to explain the ignorance of a noob. I've read a bit lately about port area for subs, and if you are a complete noob, the info can be confusing (and/or just straight up contradictory). First you have to determine what info and from where seems trustworthy, and there's several reasons why that first step alone can be very frustrating.

Next you may read the same thing over and over again, like this example - 12-16 in^2 of port area per foot. But after lots of searching and just when you think you know enough, you may find one obscure post saying something like "port area has nothing to do with box volume"...wait, what?!?! It's not just 12-16 in^2 per ft??? Not only did I (and I'm sure many others) read that on many forums before I started searching here, I also read it in a sticky here :

BL 15 – Ported box we recommend using 2.8-4 cubic feet @ 28-37Hz. Again use 12-16 square inches of vent area per cubic foot of volume.

Most people probably don't know of that $40 book or even just the need for it, and maybe some knowing of it would think these types of forums would be ample Cliffs Notes for it. Ok so I guess I'm done rambling, just wanted to explain the frustrations some of the noobs have in trying to "get it right".

Thanks to all who are spreading good info!

There's a lot of people out there that don't give a shit about how the box is and ONLY wants bass. This at least puts the people that don't give a shit about the box into an area that is somewhat good. 12-16 square inches of port area per foot would make the box usable, but not optimal unless that is what comes up for your specific setup. Some people aren't really wanting to learn why each setup needs different amounts of port area. This saves the users from putting a 15" BL in a 4 cubic foot box with 10 square inches or port area and then would also save FI from having to hear the user bitch, because their sub got fucked up.

Edited August 1, 2013 by Bassink