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View Full Version : Fi Q 18 sealed or ported? 7ft/cu...



Xprime4
12-08-2008, 08:54 AM
I ain't got a lot of space in my hatchback, something around 7,15 ft/cu internal with 3/4 mdf. Hey that's not that bad for a such little car :rolleyes:

I just bought one from BryanCain of this forum. It should show up in few weeks since i'm in canada and usps aren't the fastest carrier around. Anyway i'll be building my box prior to getting it so as it show i'll be ready to bump it

I'm looking mainly for sq, but at the same time I listen to alot of rap and i'm a lowend fanatic :laugh:

So i got two choice: sealed at 7ft/cu or tuned at something a little smaller tuned at around 28hz-30hz. Either choice, the sub will be facing the roof. if i go ported, it will be aero port facing the back of the car.

I've send that few peoples around here put it in a small ported box (like 6ft/cu) how does it sound? does it affect the lowend a lot?

Also there's gonna be a little ugly mdf adapter I did for my rearfill about few inch over the subs (maybe 3 inch over its max excursion). It might be in front of it, is it gonna affect the sq in any way?
look like this atm: http://i371.photobucket.com/albums/oo152/xprime4/Photo016.jpg?t=1228313997

yeah next box will be paint :D It won't look as ugly

thank for the help Q lovers. I hope it live up to his hype :crazy:

and btw, since the sub will be viewable from the outside of the car, any way to make that safer? windows are already tint and the sub is black so that's a plus

Xprime4
12-08-2008, 09:08 AM
and with aeroport how do i calcul the tuning? I'll be getting 2,5" aeros

mcsoul
12-08-2008, 11:05 AM
Post your max dimensions.

Consider taking out that whole rear fill baffle,
and post the new dimensions with that consideration.

skadude016
12-08-2008, 11:11 AM
works well in 6.5 cubes tuned to 30hz ( does real well from 35-45hz then kinda drops off and anything under 35hz is good but not great). really comes alive with more room though.

Xprime4
12-08-2008, 11:19 AM
37,25 x 18,5 x 22 =7,15ft/cu if i don't touch the baffle and leave 3 inch under it
If it's really needed i'll can get up to like 37,25x22x22. But i want a rear fill but maybe i can use the C pillar with some work (the pillard next to the backseat) I don't want to wall the car :D The same heigh as the backseat could do fine

Xprime4
12-08-2008, 11:24 AM
works well in 6.5 cubes tuned to 30hz ( does real well from 35-45hz then kinda drops off and anything under 35hz is good but not great). really comes alive with more room though.


Well i want it to shine in the lowend... So sealed would be better in that case?

mcsoul
12-08-2008, 11:53 AM
Build a max dimension 7.15 cubic foot) sealed box.
Throw 1000-1200 watts on it and see how you like
it. If you then want to try ported, I can give you
the lengths for 4" areo ports for a given frequency.
Don't use 2.5", too small.

If you build the 7.15 cuft box, it will net 6.9 after the woofer.
If later you port it to 28hz, you would add two 4" wide
9.62" areo ports. Your box will be 6.75 cubes at 28hz.
You will gain a lot of "peaky" output above 30hz, but you
will gain very little below 30Hz. You will have to use a 26Hz
subsonic filter. If you run sealed, you don't need to run a subsonic
filter at all.

skadude016
12-08-2008, 12:22 PM
Well i want it to shine in the lowend... So sealed would be better in that case?

you wont have the kind of output you would with ported though. dont get me wrong it doesnt **** in low end with a smaller box but its just not as prominent

dman4486
12-08-2008, 12:25 PM
I say build the large sealed and then decide if you want ports. if you do, then drill the holes and install the ports.

BryanCain
12-08-2008, 12:28 PM
Yo man, just wanted to let ya know the sub has been shipped... look for it soon.

Thanks for easy transaction,

BRYAN CAIN (baddest mother ****er of all time.)

Xprime4
12-08-2008, 12:32 PM
Yo man, just wanted to let ya know the sub has been shipped... look for it soon.

Thanks for easy transaction,

BRYAN CAIN (baddest mother ****er of all time.)

nice thank you brian
How do i know if it go the bp option on it? smell the coil with 1500 watt :laugh:

Xprime4
12-08-2008, 12:35 PM
Yeah i'll try it sealed first and then i'll drill some hole. Once the box will be sittin in the car i probably won't be able to get it out. Wow 4inch aero? I hope i'll be findind that local

dman4486
12-08-2008, 12:38 PM
Yeah i'll try it sealed first and then i'll drill some hole. Once the box will be sittin in the car i probably won't be able to get it out. Wow 4inch aero? I hope i'll be findind that local

http://www.parts-express.com/webpage.cfm?&Webpage_ID=3&CAT_ID=48&ObjectGroup_ID=143&SO=2&FTR=port&CFID=1839333&CFTOKEN=68246242

shipping won't take long

BryanCain
12-08-2008, 12:38 PM
It sounds like you should go sealed!

BryanCain
12-08-2008, 12:40 PM
I just sold some 4" ones a while back. HELL of a product.

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=268-352

Xprime4
12-08-2008, 12:43 PM
It sounds like you should go sealed!

that's quite a decission here... i'm not bumping my substage full tilt often... but sometime you just feel like it and this is where porting comes handy :rolleyes:

If i drill the hole then block them with something Could i swap from sealed to ported whenever i want :cool:

dman4486
12-08-2008, 12:44 PM
that's quite a decission here... i'm not bumping my substage full tilt often... but sometime you just feel like it and this is where porting comes handy :rolleyes:

If i drill the hole then block them with something Could i swap from sealed to ported whenever i want :cool:

technically yes....pull out the aero(s) and seal up the hole:wow:

BryanCain
12-08-2008, 12:45 PM
that's quite a decission here... i'm not bumping my substage full tilt often... but sometime you just feel like it and this is where porting comes handy :rolleyes:

If i drill the hole then block them with something Could i swap from sealed to ported whenever i want :cool:

Yes. If you "block them" you can.

Xprime4
12-08-2008, 12:47 PM
ok nice. Then i'll do the biggest I can (out of there ****** baffle :D ) and convert my box to an interchangeable one. (does that word exist in english)

8 ft/cu sealed, is that too much? will i get something descent over 45hz with a box that big

Xprime4
12-08-2008, 12:49 PM
another thing, does the aeroport facing affect the sq/spl in anyway? I won't have a lot of space to let the box "breath" if i put them facing the back of the car

I just called a local audio shop. They got 6, 5 and 4 diameter aeroport :D But they are 6" deep max.

mcsoul
12-08-2008, 01:02 PM
another thing, does the aeroport facing affect the sq/spl in anyway? I won't have a lot of space to let the box "breath" if i put them facing the back of the car

Ports back woofers up in your case.

You could put in a panel with the 2 areo ports, but it gets a little
complicated.

First, it would likely just be for spl, so you might go 32-34hz or maybe
higher. Second, you should use threaded inserts so you don't blow out
the screw holes. Third, you should use some kind of gasket, like woofer
gasketing available at parts express. So basically mount the 2 ports to
a 20" x 10" board and create an inner lip around the hole that you would
apply your gasket too when you swap out the baffles. Fourth, this is going
to sound fine sealed and you could do all of this to the same box later if
you wanted.

Don't expect it to be the loudest thing on the street just because it's an 18.
Two properly ported fi q 12's in a 4.5 cubic foot box will be louder and go deeper
on 2000 watts, than a single fi q 18 sealed on 12-1500. That's just the way it is.
But 18's do have a unique quality to the output that you should enjoy if you like
deep bass.

Xprime4
12-08-2008, 01:10 PM
Ports back woofers up in your case.

You could put in a panel with the 2 areo ports, but it gets a little
complicated.

First, it would likely just be for spl, so you might go 32-34hz or maybe
higher. Second, you should use threaded inserts so you don't blow out
the screw holes. Third, you should use some kind of gasket, like woofer
gasketing available at parts express. So basically mount the 2 ports to
a 20" x 10" board and create an inner lip around the hole that you would
apply your gasket too when you swap out the baffles. Fourth, this is going
to sound fine sealed and you could do all of this to the same box later if
you wanted.

Don't expect it to be the loudest thing on the street just because it's an 18.
Two properly ported fi q 12's in a 4.5 cubic foot box will be louder and go deeper
on 2000 watts, than a single fi q 18 sealed on 12-1500. That's just the way it is.
But 18's do have a unique quality to the output that you should enjoy if you like
deep bass.

I'm not expecting a spl increase over the type r's i had in 4.6 tuned at 32hz. Being able to get around 135 on music would be enough for me .. i'm pretty sure the Q could do that with a lot of power even sealed, will it?:confused:

This time I wanted to spend all my budget on one quality sub. i love the way an 18 sound in a club, it's so clean and deep, something the R weren't doing it good at all.

either way, when i first started gettin interrested in car audio my only goal was to be louder than my friends... now my goal is to "Wow" (see related thread which became a warzone)me with the sq.

Your design look complicated. Anyway if the output is loud enough sealed I probably won't bother making the swap :P I'm not into comp (there not a lot around) and the scene **** hard. Most people run kicker thinking there's nothin better in the world lol.

To give you an idea, every people that got a demo from me said that was the loudest **** they ever heard :(

mcsoul
12-08-2008, 01:17 PM
I'm not expecting a spl increase over the type r's i had in 4.6 tuned at 32hz. Being able to get around 135 on music would be enough for me .. i'm pretty sure the Q could do that with a lot of power even sealed, will it?:confused:

This time I wanted to spend all my budget on one quality sub. i love the way an 18 sound in a club, it's so clean and deep, something the R weren't doing it good at all.

either way, when i first started gettin interrested in car audio my only goal was to be louder than my friends... now my goal is to "Wow" (see related thread which became a warzone)me with the sq.

Sealed is easiest then, however, with more space things get interesting.
Get rid of the rear fill baffle, give that baby 8.5 cubes gross and then add
two 4" wide by 6" long areo ports and you have right at 8.25 at 30hz. That
is big and bad and sq with the q18, more airspace will make a difference
here.

Xprime4
12-08-2008, 01:26 PM
Sealed is easiest then, however, with more space things get interesting.
Get rid of the rear fill baffle, give that baby 8.5 cubes gross and then add
two 4" wide by 6" long areo ports and you have right at 8.25 at 30hz. That
is big and bad and sq with the q18, more airspace will make a difference
here.

nice' i'll be doing that is sealed at 8.5 isn't enough loud for my taste
but there won't there will be like only few inch between the aeros and the lid. any problem here?

mcsoul
12-08-2008, 01:35 PM
nice' i'll be doing that is sealed at 8.5 isn't enough loud for my taste
but there won't there will be like only few inch between the aeros and the lid. any problem here?

I'd rather put the areos closer to the floor, that way they load off the cabin
better. How much space between the output of the ports and the back
of the cabin? A few inches would be nice, if it's close to zero that is very bad.
The ports need to breath a little, then hit a wall, if the output travels along the
floor a little to get to the wall, bonus.

rasta4life
12-08-2008, 01:37 PM
I hope I am not going way out their but if you want more air pushing and you want to feel more of the umph!go with the ported sound.Just look at the physics of a ported box.

I have a pretty nice stereo,show style.When I first took my car to a show mostly everybody had ported boxes and I had sealed.I was like I can't compete with people with ported boxes.Their setup up was hitting harder than mine.Mine hits pretty hard but like the systems with ported boxes.

Xprime4
12-08-2008, 01:39 PM
I'd rather put the areos closer to the floor, that way they load off the cabin
better. How much space between the output of the ports and the back
of the cabin? A few inches would be nice, if it's close to zero that is very bad.
The ports need to breath a little, then hit a wall, if the output travels along the
floor a little to get to the wall, bonus.

well it's more like next to zero... :( port up anygood ?


I hope I am not going way out their but if you want more air pushing and you want to feel more of the umph!go with the ported sound.Just look at the physics of a ported box.

I have a pretty nice stereo,show style.When I first took my car to a show mostly everybody had ported boxes and I had sealed.I was like I can't compete with people with ported boxes.Their setup up was hitting harder than mine.Mine hits pretty hard but like the systems with ported boxes.

Space is the problem here.

mcsoul
12-08-2008, 01:50 PM
well it's more like next to zero... :( port up anygood ?


Ports up behind the woofer, against the back of the cabin is an option.
In that config, you really want close to zero space between the back of the
box and the wall. Also no flimsy obstructions above the ports.

8.25 net at 30hz with no rear fill baffle and your very next expense should
be a kick butt front stage, followed by good sound processing HU with time
correction and 3 way crossovers.

Xprime4
12-08-2008, 02:05 PM
Ports up behind the woofer, against the back of the cabin is an option.
In that config, you really want close to zero space between the back of the
box and the wall. Also no flimsy obstructions above the ports.

8.25 net at 30hz with no rear fill baffle and your very next expense should
be a kick butt front stage, followed by good sound processing HU with time
correction and 3 way crossovers.

lol i'm switching front stage every 2 months lol. My girlfriend is gonna kill me if i swap again :furious:
Anyway i bought some Id ctx65cs and I hooked them on a mb quart 4channel amp 300x2. It sound real nice and loud. As for rearfill (don't hate i'm fading in the frontstage i just hate not having a rearfill at all ) i'll be putting some entry level cdt with vc-100 tweeters.

Btw since i'm going on a trip to miami beach in 2 weeks i've removed most of the higher end equipment from the car. Still those vc-100 sound nice for being that cheap

Camaro 2010? Are you driving a prototype :D