Odd rectangular box, port dimension help

[pimpnyou204 10+ year member]

Ok I have 2 AQ HDC3 12s im building a box for and basically the dimensions of my box have to be..

28 wide

30 deep

15 height (subwoofer side facing the trunk)

11 height (facing the front of the car)

I have an extremely odd shaped trunk space to work with so i pretty much have to work with that. Now my question is can anyone figure out the depth of my port and the width of it for it to be tuned to 38hz. But heres the issue im running into i want subs facing the trunk and the port to the front, but i cant find anywhere that would calculate that for me. If anyone can help me id much appreciate it.

Thanks

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[Jh8909 10+ year member]

what car?

 

[pimpnyou204 10+ year member]

It's a 2010 altima coupe. You have any other ideas I can try? So far I've done speakers up port side.

 

[Phoenix Risen 10+ year member]

just run subs back port back, or subs up port back, with that you could put the port on either front or back,

also why the tuning at 38, i had a box at 37 and didnt like how much it limited the response or the peak it put in it.

 

[pimpnyou204 10+ year member]

I can't fit the subs and port on the same side I've only got about 28 maybe 29 squeezing on width. I'm doing 38 bcuz that's all I've ran so far. What would u suggest 35? I went to this place and first thing they said from 2 dif ppl was "your ports in the wrong spot." they say subs back port front, so that's what I was gonna try to accomplish now. I'm still learning but correct me if I'm wrong but if u want low lows it's best to put your port off in a corner or the back to bounce off of?

 

[sobe3yourself. 10+ year member]

aero ports or maybe passive radiators on the sides?

 

[pimpnyou204 10+ year member]

I've never done an aero port how do u attach them to it? Inside the box with screws and glue? And whats a passive radiator sorry for asking so many questions I've just done and redone this box about 4 5 times but each time it's better.

 

[sobe3yourself. 10+ year member]

a passive radiator is pretty much a speaker with no voice coil or magnet. it is put in the box along with your active drivers to somewhat tune your box.

a good thing about them is that you get no port noise, especially if you have a little port opening.

i am not too familiar with pr's, but you should at least check them out.

so those who say "you cant tune a sealed box" are wrong.

 

[sobe3yourself. 10+ year member]

I've never done an aero port how do u attach them to it? Inside the box with screws and glue? And whats a passive radiator sorry for asking so many questions I've just done and redone this box about 4 5 times but each time it's better.

watch this

 

[Bumpin' Goalie 10+ year member]

I agree with aero ports. They tend to limit port displacement as well which allows your space to go farther. They're incredibly easy to use. 2 4"s or 1 6" from PSP would be fine and work well.

You can find them at PartsExpress and MadiSound.

Here's the calculators you may need.

the12volt

Products Menu

Feel free to PM me with questions.

Best wishes.

 

[Phoenix Risen 10+ year member]

as far as tuning i would say go as low as possible, best thing to do is get the box designed, figure out what the internal dimensions and gross volume is (LxWxH/1728)

once you have the gross volume subtract the displacement of you woofers. to give you a rough net volume

then figure out where you want to run your port, and what the distance is to the opposite wall, the length you can make your port is that distance minus the diameter of the port. then use the calculator to figure out what you can tune it too with that port length, by the way the usable length of the port when whole is 17" when you measure the port with the flares on you have to subtract 1" to give you the usable space.

also the flares mount to the outside of the box with 1 flare and they run inside the box. how you put them together is up to you, anything from super glue to duct tape works

 

[pimpnyou204 10+ year member]

After a lot of number crunching and PMs i came up with a..

28 width

27 depth

14 height

I wanna try the aero ports and see if their what their cracked up to be plus itd be nice to tune them around pretty easily. Now my question is after putting my numbers in here..

Subwoofer Enclosure Calculators, Fraction to Decimal, Parallel, Series, Port Length and Volume Calculators

i got box volume = 4.88824

So i put it into here

Products Menu

with a tuning freq. of 36 and 1 4 in. port it told me to use a length of 3.4286852863792756 with a flare

now if i do 2 ports it tells me to have a length of 8.783370572758551

with 2 ports why is it so long and is that combing them together or each one is really 8 inches? Or am i supposed to just use one port?

 

[Phoenix Risen 10+ year member]

when you use more than one port you have to make them longer because of increased port volume, also i still think you tuning a little on the high side, run the calculator again and see what you come up with at a tuning of 32 for your port length

 

[Phoenix Risen 10+ year member]

i just ran the calc and with that box volume using 2 full length 4 inch aeros will tun you to right about 29 hz which will let i play low and be smooth through out the response curve

 

[pimpnyou204 10+ year member]

Everything ive been reading has said that the hdc3's sound better with higher tuning 36-40 but none the less i ordered 2 so i can always try them out long first and work my down as i like it.