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View Full Version : Centered port with single sub setup?



chambiec1
03-21-2008, 10:44 PM
Hey guys. My car is a '92 Pontiac Bonneville. In the back it has a folding armrest, with an access to the trunk (I believe they call it the ski hole?). Like so:
http://www.supermotors.net/getfile/584177/fullsize/img_0347.jpg

As of now, I have a standard slot ported box, 4.5^3FT at 34Hz, sub and port back:
http://www.supermotors.net/getfile/600432/fullsize/img_0388.jpg

Since my car has the hole through the rear armrest, I have wanted to try to utilize that somehow with a new box build. What I want to ultimately achieve is to have a centered port, firing through the rear armrest, with my sub firing back(or up if needed). Problem is, I don't know how to go about designing a box like this, or if it is really even possible to get it to sound decent, and ultimately be louder than my current setup.
I drew up this ****** diagram of how I would want things to be layed out:
http://img524.imageshack.us/img524/8625/centerportnb4.jpg

Now my question is about the design of this. Could anybody give me a little help/insight on how to even begin the design process like this. Or better yet, if someone has an existing design that they have done similar to this, that would be a big help.
Let me know what you guys can do, or if my idea is just wack.

-Casey

chambiec1
03-21-2008, 10:59 PM
And just for clarity, if it will work out, I would like to keep it the same size/dimensions it is now.
4.5^3 FT
36W x 17H x 18D
Tuning would be around 32-34 Hz

Falder
03-21-2008, 11:04 PM
That'd be pretty sweet if it works out.

chambiec1
03-21-2008, 11:47 PM
That'd be pretty sweet if it works out.

I hoping it does... and if it does, I am hoping the output will be better than my current box.

jnralp00
03-21-2008, 11:49 PM
probably be better to fire your sub up in this case.

Ken448
03-21-2008, 11:54 PM
have to wonder what kind of sound comes from JUST the port, and JUST the speaker..

Nova76
03-21-2008, 11:55 PM
this is the same thing i wanted to do with my box design but i dont have a fold down armrest i just took my back seat out haha its a nice way to let all the bass in but i think the way you have it in that pictre should work just have the port going straight back if needed then have it turn so its faceing the sub inside the box

rumple4skin
03-21-2008, 11:57 PM
talk with boxdesigner he has said tons of **** about all different box's. if it can be tuned to a frequency worth a **** he will tell you your specs

chambiec1
03-21-2008, 11:59 PM
have to wonder what kind of sound comes from JUST the port, and JUST the speaker..

Queż

miker
03-22-2008, 12:51 AM
This is my next build, but with an aero.

rumple4skin
03-22-2008, 12:52 AM
no **** well post something on it after you get it done i would like to do this aswell but the box makers in my home town are morons

chambiec1
03-22-2008, 12:58 AM
This is my next build, but with an aero.

Care to elaborate a little?

miker
03-22-2008, 01:37 AM
Care to elaborate a little?

I'm building a 2.5 c f box with a 25.25in x 6in tube coming out the back and porting through the center ski hole.

chambiec1
03-22-2008, 01:46 AM
I'm building a 2.5 c f box with a 25.25in x 6in tube coming out the back and porting through the center ski hole.

Any design pics? I'm just trying to keep my options open.

Is the aero going to be internal or external? What about sub placment?

dbhittin
03-22-2008, 01:49 AM
sub up/port into arm rest.. did that in my caddy.. worked awsome.. u can also take the rear speakers out of the deck, if their there.. that helps

miker
03-22-2008, 11:52 AM
Any design pics? I'm just trying to keep my options open.

Is the aero going to be internal or external? What about sub placment?


Well.. It jsut snowed a **** load.. And I was wanting to use the table saw for this build, so I don't think it's happening for a little while...

Anyway, the Aero is going to be internal and external. I'm thinking of mounting the sub on the top so the amps don't get in the way of it.

Idk, it's not really anything special.. Just something I'm hoping will get louder than porting to the rear of the trunk..

bjfish11
03-22-2008, 12:10 PM
What about something along these lines?

http://i171.photobucket.com/albums/u282/bjfish11/new/untitled.jpg

rumple4skin
03-22-2008, 12:13 PM
i don't know much about box design( just payed some *** hole to make my box) but this looks like about how it will look(as long as boxdesigner says it can be tuned to the right frequency) and i believe you can leave the sub pointed to the back of the trunk if you like as well i believe and just mount the amps on top of the box instead of in back

SHiZNiLTi
03-22-2008, 12:29 PM
Why not a 4th order bandpass?

http://www.carstereo.com/Images/SealedBP.gif

This way the trunk gets no vibration at all with the sub sealed inside of the box.

All of the bass output is coming out of that port.

rumple4skin
03-22-2008, 12:30 PM
lol thats a better idea=)

chambiec1
03-22-2008, 03:09 PM
Why not a 4th order bandpass?

http://www.carstereo.com/Images/SealedBP.gif

This way the trunk gets no vibration at all with the sub sealed inside of the box.

All of the bass output is coming out of that port.

I've always read you need more space than a traditional ported box to do a proper 4th order.

bjfish11
03-22-2008, 03:31 PM
The 4th order 80 designed me for my Q, was just barely larger than the ported box I had it in before.

chambiec1
03-22-2008, 03:59 PM
The 4th order 80 designed me for my Q, was just barely larger than the ported box I had it in before.

How was the output of the BP compared to your ported box?

bjfish11
03-22-2008, 04:32 PM
How was the output of the BP compared to your ported box?

Judging by ear... Id say output was very close to the same. I think the SQ of the BP is better. For comparison, it was in a 2.5 cube @ 32 hz ported box, not sure on the specs of the BP.

chambiec1
03-28-2008, 08:04 PM
Bump for more suggestions.

IDSkoT
03-28-2008, 08:37 PM
It can be done. I think the SPL is boosted a lot with this set-up.


But, I'd go with the 4th Order Bandpass.

I'm actually thinking of doing this for my car ('98 Mustang) firing the port right into my cab.

chambiec1
03-29-2008, 08:27 PM
Would something like this work? I've seen it done with 2 subs, but am not sure if it would be effective with only 1. Would it work better with the sub up?

http://www.supermotors.net/getfile/620764/fullsize/nothing1.jpg
http://www.supermotors.net/getfile/620765/fullsize/nothing2.jpg
http://www.supermotors.net/getfile/620766/fullsize/nothing3.jpg

I'm no acoustic engineer, but would a box like this sound/work properly? I'm unfamiliar with the travel of sound waves vs. placesment of sub/port, so help would be appreciated.
-Casey
EDIT: designs by JBLCAMRY, *not to spec*

miker
03-29-2008, 10:09 PM
Umm, that was my first idea.. WAs told that port noise would be terrible.

chambiec1
03-29-2008, 10:36 PM
Umm, that was my first idea.. WAs told that port noise would be terrible.

Even with sub up? I know alot of guys do it with multi sub setups, but is it the single sub causing port noise to be present?

chambiec1
03-30-2008, 10:51 PM
Alright, so if I were to go with a 4th order BP, how big are we talkin to fit my 15" Kicker L7?
My dimensions I have to work with are 36"(width) X 17"(height) X whatever depth(although I found that my current box, which is 20" deep, was a perfect fit through the trunk opening).
I listen to primarily rap, and it is a daily box. I like my lows alot. My current box is 36"x18"x20", 4.5^3FT tuned to 34Hz, and would like to drop my tuning by a little bit. If it matters I am running just about 1500wrms in it's current config.

Could anybody give me some suggestions on a design for a proper 4th order, given my sub and measurements? Any help is appreciated.
-Chambie

chambiec1
03-31-2008, 07:38 PM
Ugh... I just don't know what way to go. I know I want to go louder, but I have no idea how I would achieve this with my current equipment. At this point in time I am open to any suggestions. I've gotten to the point where I am so use to my current setup, that it's barely pleasing to me anymore.