HELP!!! SUNDOWN SA-12 2 of them port size for my box help

[BOOMINGRANDPA 5,000+ posts]

yes per chamber I can change it pretty easily so far I just have everything with a couple very small screws until everything is finalized then I plan on liquid nail and screws what would be the ideal depth a aeroport size for them I cant gi wider because my trunk size but I can make the 24 shorter

cool it u can change it u good.. if box is 15" high probably need 2-2.5? wide slot port per sub (have to check port velocity before settling on port area though) ok i ran #'s some through wins program looks like u could do 2" w x15h port 32" long (if u can get box down to 2cfad per sub) should tune to 33-34hz so even after subtracting the port boards looks like u need to shrink box .35-.4cf per sub to get it to the 2cf ad size (thats after port sub and port boards) depends how low u want to tune it..

 

[poolman966554]

You can ask this size box vs port diameter, and length all day and get no where. all 3 parts of the equation effect each other when any one of them are manipulated.

The absolute most bestest way to understand what i mean is by watching this:



Its really not that hard.

If your determined to use your existing box, you can use the info from the video to "work backwards" to make your existing box the proper size, and see the correct port length

Edit: i forgot your wanting areos vs a slot described in the video.. So, to calculate a cylinders area is to use " V=πr 2 h"

yeah f that.. its Volume = pie x radius squared x height.

EX: 4" port is " 2" x 2" x 3.14 x length of port = port displacement from total box volume. Make sure to subtract that number from total box volume, along with sub displacement when viewing in Winisd

 

[THATpurpleKUSH 5,000+ posts]

Shrink the 24 inch side to 16.5 and use a 4 inch round port that is about 13.5-14 inches long per side. It's the closest you will get to ideal with a box that has separate chambers.

 

[poolman966554]

Shrink the 24 inch side to 16.5 and use a 4 inch round port that is about 13.5-14 inches long per side. It's the closest you will get to ideal with a box that has separate chambers.

well your no fun.. lmao

 

[precisecnc]

that's sounds easy I'm rolling with this idea thanks

 

[Oinkypig 10+ year member]

use torres calculator. if your building for two sundowns and you really want to make an impression than build yourself a 6th/4th order bandpass. look up youtube to know what im talking about specifically 6th order.

 

[BOOMINGRANDPA 5,000+ posts]

that's sounds easy I'm rolling with this idea thanks

if u are putting port on front of box make sure it's wide enough for port/sub to fit (may have to go 17.5" or so)

 

[Oinkypig 10+ year member]

IF you get to hearing port noise you can tune it down from there. people say 10-18 in2 per ft3, but you could experiment with higher values of port area but you sacrafice internal volume at the expense of tunning lower when you go to greater port area which is why you shouldnt nerd out over what other car audio forum members consider intimidation. i personally recommend 10-18in2 because its easier than what others are trying to explain to you. perhaps two subs one port vs two subs two ports. 6th 4th two ports one port push pull

 

[Oinkypig 10+ year member]

"back in the day i used 10 sq inches per cubic foot of box as a guideline. but that was dealing with smaller woofers. with todays high xmax woofers more port area is recommended, usually around 15 sq in per cubic foot of volume." for example, this is the most boring car audio has been in history. Thank You. This is my experience as well. But don't tell a "professional noob" to run 8-12in^2 port area.......

 

[shredder2]

"back in the day i used 10 sq inches per cubic foot of box as a guideline. but that was dealing with smaller woofers. with todays high xmax woofers more port area is recommended, usually around 15 sq in per cubic foot of volume." for example, this is the most boring car audio has been in history. Thank You. This is my experience as well. But don't tell a "professional noob" to run 8-12in^2 port area.......

I think the 8-12in^2 is referring to a round/aero, really the best bet is to model the thing for up to rated and leave the port velocities a little low so more power can be added eventually. Those Sa's always seem to like a bit more than rated and don't seem to mind the extra power. Slot, sure... 14-17in^2 is a good bet so 15in^2 is probably close.

 

[Oinkypig 10+ year member]

to step away from sealed type enclosure, is to go ported. the smaller the port the more air trapped inside and it sound more like a sealed enclosure. I would say for two 12's hes looking for spl. Build a bigger port to move more air in and out of the box and if you make it so big that you encounter ear pain aka port noise than just turn down the gain and swap ports to different frequencies. I personally would move away from say like 20 or 30 and would like to tune near 40hz. Owned and built 2.0cf @ 41hz with 5x13.5"(67.5in2)

) ported and it sounded more like a 4.5cf box because it moves air ?at a slower rate? and sounded more sq than spl to me. looking back, i couldve change port to 4x13.5@41hz at this point to minimize port noise. the box was built and logged in the forum somewhere, it was a 12" re xxx v1 on 2-2.5k amp

 

[shredder2]

to step away from sealed type enclosure, is to go ported. the smaller the port the more air trapped inside and it sound more like a sealed enclosure. I would say for two 12's hes looking for spl. Build a bigger port to move more air in and out of the box and if you make it so big that you encounter ear pain aka port noise than just turn down the gain and swap ports to different frequencies. I personally would move away from say like 20 or 30 and would like to tune near 40hz. Owned and built 2.0cf @ 41hz with 5x13.5"(67.5in2)

) ported and it sounded more like a 4.5cf box because it moves air ?at a slower rate? and sounded more sq than spl to me. looking back, i couldve change port to 4x13.5@41hz at this point to minimize port noise. the box was built and logged in the forum somewhere, it was a 12" re xxx v1 on 2-2.5k amp

I'm kinda confused by your explanation regarding this enclosure design, too many things are vague or don't make sense... lol... this is one I did recently, ported for up to rated and really got loud and low as well...

 

[THATpurpleKUSH 5,000+ posts]

to step away from sealed type enclosure, is to go ported. the smaller the port the more air trapped inside and it sound more like a sealed enclosure. I would say for two 12's hes looking for spl. Build a bigger port to move more air in and out of the box and if you make it so big that you encounter ear pain aka port noise than just turn down the gain and swap ports to different frequencies. I personally would move away from say like 20 or 30 and would like to tune near 40hz. Owned and built 2.0cf @ 41hz with 5x13.5"(67.5in2)

) ported and it sounded more like a 4.5cf box because it moves air ?at a slower rate? and sounded more sq than spl to me. looking back, i couldve change port to 4x13.5@41hz at this point to minimize port noise. the box was built and logged in the forum somewhere, it was a 12" re xxx v1 on 2-2.5k amp

A lot of misinformation in there.

 

[Oinkypig 10+ year member]

A lot of misinformation in there.

his point in question has to do with cabin pressure. oinkypig

 

[Boomin_tahoe 5,000+ posts]

wtf is oinkypig?