Help me plan this whole thing out!!!

[TwistedMovistar 0]

i just put the order in for a 12 d2!!! now i must have the box ready when it gets here!!! so her is what i have to work with

*i have a 2003 mustang and a hifonics 1500d

*i want to go ported around 3.0 with a tuning of about 32-29 ( i need help there)

* i listen to mainly rap so i want a loud loud bass!

the box i have in mind is a 14hx31x16d which equals 3.091 internal volume.

-when i get ready figure out port tuning, will i put in the calc that the box is 3.0 or 2.7 due to the port and driver displacement?

-what is the difference between tuning to 29 or 32 sound wise?

-is 3.0 internal volume to big for a mag?

-would i be wrong for just spraypainting the box instead of carpeting?

[KU40 173]

if you listen to mainly rap, I'd tune to the higher figure, 32 hz. When you plug into port calculations, you have to subtract out the port and driver displacement. With Mustangs I have seen the most problems not with the size of box that'll sit in the trunk, but the size that will fit through the opening. You have to be careful there, as I think the trunk opening is a little small, so fitting a larger box in there may be a little more difficult.

if you do 3.0 cubic feet before all displacement, you'll be pretty good. a port tuned to 30 hz with decent amount of port area will displace close to .5 cube, so after that, the volume the sub will see is down quite a bit.

difference between 32 and 29........not a ton. 32 would be a little more boomy in the 35-50 range, and the frequency response wouldn't be as flat as the 29. but the difference would be pretty small.

about finishing........it's up to you. I wouldn't spray paint, as I haven't had good luck with that. but if you use a regular paint and brush it on, you can yield pretty good results. I've never carpeted a box, though. i've either painted them or leave them bare (which is what I usually do).

[TwistedMovistar 0]

i have met the don't fit bug of the mustang i am at my limit with a 13.5 max to go thru the trunk. in order to get it in i will have to take out eh backseat that gives me a 14x 32 opening. my last questions are:

how do you make the box air tight?

do you use selant inbetween the wood peices then screw it in?

would you adivse againt using a round port?

how do i make a plug for the port to convert it to sealed?

what type of screws did you use and how far apart?

[KU40 173]

you need to use wood glue to hold all joints together. the glue is really what holds the box together,and the screws just hold the joints together while the glue dries (though I use clamps too). they may help a little with structural integrity, but not a ton.

after you get joints together, run over them from the inside with some sort of caulk or silicone, or something like that. that will insure it's airtight in terms of joints.

there really is no difference in using a round port or slot port, or anything. I would say that a round port may be a little more difficult here, though, because it would have to be so long. you would probably have to use some angles and elbows.

what I have done to seal off my ports is pretty basic. just cut a piece of wood that will cover the hole, and you just screw it over the hole. that's it. I had a couple air leaks around mine, though. But for this I wouldn't recommend a liquid (or gel like) sealant like you used on the joints on the inside. I would use something like rope caulk, so that you can take it off and reuse it again as you plug and unplug the port.

screws I use are just 1.5" drywall screws, about 5 inches apart.

[TwistedMovistar 0]

ahh so like a gasket sort to say around the port for the wood to mate to. wood glue, like gorilla gluein between them and screw them, them chalk the inside right? i feel like making two boxes a sealed and a ported now. one other question

to be clear

if the volume of the box is 3.0 internal before any displacement. do i plug that into winisd to find the port length or 2.5 with displacement of port and driver already in it?

it is saying that if i use a 3 inch round port it wil need to be 5.32 inches that is not long atall, is something wrong

[KU40 173]

you have to plug in the number after all displacement. so 2.5. however, you have to realize that the port will be different for the 2.5 box than for the 3.0. so you may not end up with 3.0 total.

as for the port, you're gonna need more than just one 3" port. that only gives you 7 square inches of port area. I suggest you at least triple it.

[TwistedMovistar 0]

ok i think that i will get it right now. i just got back from playing with my memphis sub with 200 watts.

* first it was in a leaky ported box(1.5 @ 32), sounded like wet A**. all the bass was on the outside of the car.

i put it back in a cubic ft sealed box and set the settings and let it rip.

i patched up the ported box and left the settings like they were. IT IS A BIG DIFFERENCE!!!!!! GET LOW ACTUALLY GETS LOW!!! the difference a small air leak can do even on a ported box. makes me think about what the magnum will do with just 500 watts in a air leak free and bigger ported box!!!

with the settings the same going from sealed to ported, i sounded like it tripled output. sealed with the volume at 29 sounded like ported at 8. it is amazing!!!

Edited July 11, 2004 by TwistedMovistar

[TwistedMovistar 0]

the las questions are.

what is the displacement for magnum 12?

i have a port of 12.5x3 that is 34 inches long. my box is 18 inches deep so there are only 2 turns is that enough port cross area is 37.50 is this ok

i am just gonna buy a wood sheet and cut it mysel, last time i got a bad cut from home depot!

Edited July 11, 2004 by TwistedMovistar

[KU40 173]

i would figure displacement to be around .1 cubic foot.

is your box 18" deep on the inside? if so, that only gives you 15" of depth for the first part of the port, because you have to leave 3" from the back wall for the waves to turn around (have to keep the distance to every wall 3", whether it be side or front and back). add in the .75 for the front baffle, and you have 15.75" on the first portion of the port.

now onto the second portion, which is starting at the back wall. you will gain 3.75" from the turn (you measure down the center of the port, so if you'd draw a line down the center of the whole port, this 180 degree turn isn't just a flip around. there is a rectangled edge there, and you have to account for that.). that will give you 19.5" so far. your second piece of wood will have to be 14.5" long to get to the full 34".

now if that is 18" deep on the outside......it will be a little more difficult. there is another problem if that's the case, which will probably force you to change your port.

[TwistedMovistar 0]

yeah the box is 18 deep on the outside. i don't see how it would be a problem, souldn't i just adjust the numbers by .75? so i would leave 3 inches from the back wall instead of 6? i thought that you had to double the width of the port, take that number and that should be the length from the back wall? so in the tunrs i would gain 3.75 instead of just .75?

*EDIT: i see now thati should only leave three inches from the back wall.

but the thing is now that i will get 3.75 inches in the turns instead of just .75?

* this is the box that i wass looking at and adjusting my numbers from

EDIT 2: I just found my secong mistake.

* my last question is how do i calculate port displacement?

and what are the differences in have a port cross area of 37.5(12.5x3x34.83) and43.7512.5x3.5x41)? would my 12.5x 3 be good enough?

Edited July 12, 2004 by TwistedMovistar

[Tirefryr 1,742]

Changing the port will effectively alter the tuning frequency and the enclosure volume. the 12.5x3 will do fine for the MAG.

[KU40 173]

port displacement is just port width + .75 (to allow for the wood) X height X depth. as for the rest of your post, I couldn't understand half of it.

the problem with 18" on the outside is that now you will have to have two port 180's (or three boards to make it). but the problem with that is that your third board is only going to be something like 3-4" I think. Which barely covers the turnaround opening right there. I don't know for sure that it effects the sound in a negative way, but I just like to be safe and have each board go at least 1/3 of the way into the box, so that the waves know they are going down a path. hard to explain, maybe it makes no sense, and maybe I'm just wrong. but i'm just conservative like that.

[TwistedMovistar 0]

now i see what the problem with that would be.

the question that i was trying to ask was,

is there a difference in sound if i use a 12.5x3 with the proper length tuned to 28 or a 12.5x3.5 witht the proper length tuned to 28?

what is a good port cross area to have on a ported box in the 3.0 cubic ft range?

[KU40 173]

either will work fine

[TwistedMovistar 0]

so does anyone know for sure if there is a problem to a port wall being only 3-4 inches if the box is 18 inches deep?

[Tirefryr 1,742]

No problem.

[TwistedMovistar 0]

ok right now i have a box that is 14x30x18 3.4 cubic feet before displacement 3.0 after port and driver tuned to 28 using a 12.5x3 port lenght is 37.75.

how much does .75 change a ports tuning, it is not like this is for competitions just street.?

i see the magnum has a 11 1/8 hole. i don't think that i can hit that right on drawing it out by hand. can i cut an 11 inch whole, or does it come with a plot to cut out?

[dozure 0]

if you go to Lowes, over with all the tools they have a large compass. It's basically a stick with a pencil clamped onto one end, and a sharp nail on a sliding piece so you can adjust the diameter of the circle. Really simple to use and only cost about $4 if I remember correctly. I use it all teh time it's great. You can also use the string/nail method, but I've had less than desireable results with that.

All you gotta do is adjust the nail until the distance between the tip of it and the tip of the pencil point is 5-9/16" and stick the nail where you want the center of the circle and turn it. whalla! perfect 11-1/8" circle.