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View Full Version : Box Design Help for 18" FI Q w/BP, 4" Aero Ports...



snb778
08-11-2008, 03:08 AM
Whats up guys...

I want to build a new box for my Q. I think it will give me just the little more output that I'm looking for.

My max dimensions give me 6.7Cu. Ft. before port and sub Disp.

I have 4x 4"wide by 10" length Flared Aero Ports

I would like to tune it to 30Hz. I don't know how to figure out how long to make the ports, or how many I would need to use.. I would like to go for 3 if possible.... Pretty sure I don't have room to do a slot port. can someone help me out, or give some recommendations.?? Thanks

oh, the box would be 34x24x14.25 as of now

Fs: 24.5 Hz | 23.8 Hz
Re: 0.7 Ohms/coil | 1.4 Ohms/coil
Qms: 5.66 | 5.73
Qes: .64 | .63
Qts: .58 | .57
Mms: 322g | 342g
Cms: 0.13mm/N | 0.13mm/N
Sd: 1210cm^2 | 1210cm^2
Vas: 268 l | 268 l
Spl: 89.7dB 1W/1m | 89.4dB 1W/1m
Bl: 10.4 N/A | 15.1 N/A
Xmax: 27mm
Rms: 1000W
Sealed box: 4-8 cuft
Ported box: 6-10 cuft @ 28Hz
Sub OD: 18.500”
Cut ID: 16.750”
Mounting depth: 10.000”
Displacement: 0.24cuft

mlstrass
08-11-2008, 08:16 AM
precision ports has a calculator on their site...

mlstrass
08-11-2008, 08:17 AM
http://www.psp-inc.com/

snb778
08-11-2008, 01:01 PM
yea but that doesnt telll me how much port area is required by my sub... That site showed I could use 2 ports...when that isn't enough for my sub.

well after just toyin around with that site... looks like I would need 3 or 4 longer ports than what I have.... or I need 2 6" aero's :-( Will PVC work ALMOST just as well?

snb778
08-11-2008, 01:44 PM
bump..... need help

snb778
08-11-2008, 02:58 PM
bump... someone please help!!

bass-aholic
08-11-2008, 03:05 PM
IMO use 3 4" ports and pvc will work just as good if you dont care about how it looks(your not gonna see it anyways).

snb778
08-11-2008, 06:02 PM
why is it that some people say don't use PVC?? Can someone please help!!

I am going to just use 3x 4" ports... I want to tune it to 30Hz. How long would they need to be.. Yes, they are flared. Thx!! 6.7 cu. ft. before Disp. and port, so please take that into account when calculating

snb778
08-11-2008, 07:20 PM
ttt.............................. .............................. ...........................

mlstrass
08-11-2008, 08:29 PM
there's plenty of online calculators to help you out...

snb778
08-11-2008, 11:30 PM
correct, but they don't tell me how much port my sub wants to see on it's box,and that is where I need help.

snb778
08-12-2008, 03:35 AM
ttt

maniackilla
08-12-2008, 05:13 AM
yes they do, read them. your just asking other to go plug the numbers in for you. links have been provided are sticky's are placed in discussions for a reasons. There is no sense for you to agree or disagree with some one and turn around and say "I'll just do this then, thats all I can do, It'll be good enough .... right?!?!?" .... your leading the thread into recursion, learn those things first *again, stickies*

If you dont give a **** on this apparent setup, you shouldn't have bought it. Let me take it off your hands. I've a a 7.3 cube box at 32 hz that'll fit right in my TRUNK with nothing but a 30x35" baffle replacement.

/end rant

just read up on the information provided man, or lemme know if you wanna sell it

snb778
08-12-2008, 01:17 PM
yes they do, read them. your just asking other to go plug the numbers in for you. links have been provided are sticky's are placed in discussions for a reasons. There is no sense for you to agree or disagree with some one and turn around and say "I'll just do this then, thats all I can do, It'll be good enough .... right?!?!?" .... your leading the thread into recursion, learn those things first *again, stickies*

If you dont give a **** on this apparent setup, you shouldn't have bought it. Let me take it off your hands. I've a a 7.3 cube box at 32 hz that'll fit right in my TRUNK with nothing but a 30x35" baffle replacement.

/end rant

just read up on the information provided man, or lemme know if you wanna sell it

FYI.... the link provided for me DOES NOT give me what I need!! its a totally general equation.. as I said.. it doesnt account for how much port each specific sub needs... The link provided says I can use 2x 4" aero's for an 18" sub, that needs much more than 2... so no, not / end rant.

Buck
08-12-2008, 01:18 PM
i would go bigger than 6.7 cub ft. maybe you should look at a 15 instead if you can

snb778
08-12-2008, 01:21 PM
15 won't give me the output I want... I can go down to 6 cu. ft. and still be within specs of FI... Keep in mind people.. there are people running FL BTL's in 4.5 cu. ft

and maniackilla... I just looked through all of the links in the sticky for enclosure design... not 1 site came even close to aero port calculations

anybody know based on the specs I posted how much port I even need... lets start there

mlstrass
08-12-2008, 02:23 PM
Q will do fine with 12^2 per cube if doing a normal slot port and the general rule when using aero's is that you only need 1/2 of that amount. Now figure out your gross box size, account for the space the sub & aero's will take up, and see what you have to work with...

Random1010
08-12-2008, 02:26 PM
I have 10 cubes for 2 18"s and I went with 8 4" ports

snb778
08-12-2008, 02:52 PM
Q will do fine with 12^2 per cube if doing a normal slot port and the general rule when using aero's is that you only need 1/2 of that amount. Now figure out your gross box size, account for the space the sub & aero's will take up, and see what you have to work with...

I can't do that until I find out how much port I need... sub disp. is .123 i believe... again though, I dont know what this Q wants for port. This is what I would LOVE for someone to figure out for me who already knows how to figure it out. I've looked through stickies, I've search for links, i've looked at some tutorials..gave me nothing.

Im simply looking for someone to say, "ok, for THAT SUB... 6.7 cu. ft, to tune to 30Hz with 3x 4" Aero's, they would have to be ____ long, giving you xx amount of port area"

im sure there are TONS of people out here that know how to do this, I don't get why its been so difficult getting help.

mlstrass
08-12-2008, 05:02 PM
What do you mean "how much port it needs"??? It needs 12^2 per cube of box. Pick your tuning, figure out how long they need to be, calculate how much volume they take up, etc...

It's all there for you to figure out...

mlstrass
08-12-2008, 05:03 PM
And once you figure out how to calculate it once you'll have that knowledge going forward...

snb778
08-12-2008, 05:29 PM
as i've said.. the reason I want to go ported is because its not loud enough for my preferances... 15 wouldn't cut it.. im already downgrading from 2 15" Type R's ported off of 3000watts... I wanted to get a smaller, better quality driver that could get just as loud... everyone was talking about their 15 flexing, and their 2 15's sealed flexin, so I was hoping this could get the job done...

6.7 is still within recommended specs.. I at least want to try it before I ditch it... know what I mean

snb778
08-12-2008, 07:53 PM
ttt

c'mon.. theres only like 50 people on here that build boxes

mlstrass
08-12-2008, 09:21 PM
what you want is a design and there's plenty of guys on here who do designs for a few $$$.

Otherwise just take a few hours to figure it all out as it's not that hard.

You would probably end up around 6^3net after the sub, ports, and bracing, so it should work...

snb778
08-12-2008, 09:43 PM
MOST guys on this site want 20 bucks for a design... I already have the box design.. I just need to know how many ports I need, and how long... something that should be VERYYYY simple, and IF i knew how to do it.. I wouldn't charge people for it... seems like basic help to me...but im getting to frusterated waiting for help so I just might do that soon.. next day off is sat. i think.

mlstrass
08-12-2008, 11:12 PM
a 6cube box needs 72^2 of port area for a Q. You need around 1/2 of that if using aero's, so 36^2. 3 4" aero's would do the trick. For a 30Hz tune they need to be 16.89" long.

Each port will take up .12^3 of space, so .36 total. Add .36 to the disp of your sub and that total is what you need to add to 6cubes for the gross box size.

Now you can spend Sat building the box...

snb778
08-12-2008, 11:25 PM
Thank You!!!

seriously.
how do you know how much port this sub needs though, so in the future I can have that stat. ready.??

I almost want to pay you just because it was so hard to get an answer from someone, and i was probably 12hrs away from payin someone for a design anyways. PM me your email and ill send ya 5 bucks if you have paypal... im going to take the box out on fri, and actually sat. Ill prob. build some cardboard boxes to see what kind of max dims I can get... problem is I can only have itbe 14.25"tall... I've had a box 36"wide, but it was like 22" deep... so I figure i'd go a little less wide, and a little deeper to compensate.. IF possible

do you know if the less port'S=better... like 1x 10" port vs. 3x 4" ports??

skadude016
08-12-2008, 11:28 PM
6.5 cu ft tuned to 30hz exact same tuning/box and woofer you are using.

http://photos-d.ak.facebook.com/photos-ak-snc1/v311/44/15/208500660/n208500660_30686835_7959.jpg

skadude016
08-12-2008, 11:30 PM
let me know if i can help i have all the specs for it :)

snb778
08-17-2008, 01:47 PM
ok, well I just went and measured my trunk... I have a little more room to work with... External Dims, I can get 7.1cu.ft. AFTER port and displ.

So that being said...how long should the ports be (im using 3) to tune to 30Hz? someone help me out here, im willing to pay for a quick answer

skadude016
08-18-2008, 12:00 AM
ok, well I just went and measured my trunk... I have a little more room to work with... External Dims, I can get 7.1cu.ft. AFTER port and displ.

So that being said...how long should the ports be (im using 3) to tune to 30Hz? someone help me out here, im willing to pay for a quick answer

13.97 inches for each port including port flare! enjoy

snb778
08-19-2008, 07:25 PM
Started the build today... I dunno if i'm even going to be able to do this.. dunno if there is enough clearance to get the ports in with out hitting the sub, BUT i should be ok considering the box is 38" inches long.

I only have like 2 hrs a day from when I wake up and go to work +watching some of the olympics... work every day through thurs., then have a wedding rehersal fri., then wedding sat. then work sun. evening..................ill get some pics when I have time

thanks for all the help guys

mlstrass
08-19-2008, 07:49 PM
car audio>olympics