Port Area vs Box Tuning: Please help, getting frustrated.

[bkolfo4]

I have run a BTL 15" in just under 3 cuft with eighty square inches of port and it sounded great. Don't let the volume vs. port area screw you up. The 2 are NOT related. That is just a very general suggestion to keep everyone from repeatedly asking.

Stick with 3-5 cuft, 45 sqin port minimum (or I have done as little as 2 4" aeros), and tune a little higher if you are tight on space.

You need room for airflow in and out of the port inside the box. General guide is 1x the diameter clearance behind the port (so a 4" port would need 4" minimum from the end of the port to the opposite wall).

edit - The pic in my avatar was my suburban - 11.8 cuft tuned to 34 Hz with 386 sqin of port area. 157.7 dB and peaked at 37 Hz with (4) BTL 15's.

[Bakerman]

1st of all, an 18" flared port is only 17" effective length as a port. it even says that in the description.

Okay, so maybe I'm misunderstanding this. I thought that if you have a port, that w/ two flares is a total of 18" long, then the air would really be seeing 20" of usable space. I was thinking that for each flare you have, the air was seeing another inch that what was really there. Did I have this backwards, and and 18" flared port is really seeing 16"?

[Bakerman]

Is this in an SUV? Subs forward/port up isnt the best way to go in an SUV..

No sir...this is a hatchback focus...very small hatch. I've currently got a setup that is sub up/port back...but I got a lot better air movement when I had sub forward/port up. Just the way the roofline is on this particular vehicle.

[skittlesRgood]

1st of all, an 18" flared port is only 17" effective length as a port. it even says that in the description.

Okay, so maybe I'm misunderstanding this. I thought that if you have a port, that w/ two flares is a total of 18" long, then the air would really be seeing 20" of usable space. I was thinking that for each flare you have, the air was seeing another inch that what was really there. Did I have this backwards, and and 18" flared port is really seeing 16"?

its exactly as i described. the port isnt 18" before the flare, its 18" with flare. when you do any type of flare you measure from about the middle of the curve, not the end. so 17" effective length here.

[The Orange Goober]

Ok guys, have a question, i havent used Aero/Precision Ports all that much...i want to change my box now from the slot port to 2 4" Flared Precision Ports/Aero Ports...correct me if im wrong but Aero and Precision Ports should be the same?

Ok a little background on what i have now, 2 Orion H2 12.2s... Current box is 4Cf^3 after all displacements...tuned @ 30Hz (little lower than my liking was just testing..still sounds good though)

I want to change my box to have 2 4" ports im just unsure of how long i need to make the ports as i havent had a whole lot of experience with the flared ports...I want to raise the tuning to 32Hz as thats my preference....now just need to know how long to make the ports...NOW will using the Aeros, allow me to downsize the box being as its not taking up as much internal volume as the slot port is? if i have to keep the same dimensions that is fine...but if i can downsize due to the ports not taking up as much space thats great!

Overview:

*(2) Orion H2 12s

*(2) 4" Flared Precision Ports

*Current Box Dimensions - 30"W-15"H-24"D (Width AND Height are MAX Dimensions Can MAYBE fit Wider box if depth is reduced)

**Would Like To Have the new box @ 32Hz with 4Cf^3

*Sub Displacement - .18 Per Woofer

Any and all help is greatly appreciated!

-Daniel

[fecupe2001]

Ok guys, have a question, i havent used Aero/Precision Ports all that much...i want to change my box now from the slot port to 2 4" Flared Precision Ports/Aero Ports...correct me if im wrong but Aero and Precision Ports should be the same?

Ok a little background on what i have now, 2 Orion H2 12.2s... Current box is 4Cf^3 after all displacements...tuned @ 30Hz (little lower than my liking was just testing..still sounds good though)

I want to change my box to have 2 4" ports im just unsure of how long i need to make the ports as i havent had a whole lot of experience with the flared ports...I want to raise the tuning to 32Hz as thats my preference....now just need to know how long to make the ports...NOW will using the Aeros, allow me to downsize the box being as its not taking up as much internal volume as the slot port is? if i have to keep the same dimensions that is fine...but if i can downsize due to the ports not taking up as much space thats great!

Overview:

*(2) Orion H2 12s

*(2) 4" Flared Precision Ports

*Current Box Dimensions - 30"W-15"H-24"D (Width AND Height are MAX Dimensions Can MAYBE fit Wider box if depth is reduced)

**Would Like To Have the new box @ 32Hz with 4Cf^3

*Sub Displacement - .18 Per Woofer

Any and all help is greatly appreciated!

-Daniel

I haven´t work with those subs, but 2 4" aeros might be a little bit small for them, i would wait for someone to give you a better input about that, taking into account the dimensions you just gave, box would end bigger than the 4 c/f you want since aeros take less internal space of the box, for 2 4´s you would need a box 14" x 30 x 24" with ports 13" long each one to end up with 4 c/f after displacement using two 4" aeros.

On the other hand, if you do need more port, then i would suggest 3 4´s or even 2 6´s , said that, with 3 aeros i would get a 14.75" x 30" x 24" box dimensions and 20" long each port, that would end up with 4 c/f and 3 4´s on a 32 hz tuning after displacements...