I'm going to attempt this install when the weather breaks https://www.fiero.nl/forum/A...030204-1-019876.html and the box install should be easy because I will use my existing behind the seat subs from this project https://www.fiero.nl/forum/A...050818-1-049964.html and just remove the backs. I like the sound of a ported box over a sealed and I'm happy the way I designed them. I have one port on the side of the box.

but my question is would it make any difference if I ported the box on the other side as well? Would I dramatically change the sound?

hate to say but you might of been better off porting the top. looking at the width and knowing how tight it is behind the seat (I have a cutout firewall box with a 10" vega) your ports are going to be firing right into the computer box and if you did the other it would be right into the seatbelt cover (I had to cut mine up to get the box to fit right) So you'll actually be choking the ports kinda like cupping your hand over them. also the chances of buzz and rattle will be higher in doing this. you MIGHT have enough room though. hard to say without having the box in the car for a trial fit. One idea though.. slap an Elbow on there to fire the waves out towards the front. heck they might channel the sound out and around the seat instead of firing them into the back of it like mine. best of luck!

Thanks for the reply. Info at this link claims the ports should be a few inches away from the driver though. http://diyaudiocorner.tripod.com/faq.htm I may just make all new boxes anyway. These are 1/2 MDF and I'd probably be better off with 3/4 with the new subs I purchased. I've been using these boxes for a couple years now in two different GT's and I made sure there was about 4 inches of space between the port and the center console but the top does make more sense. Still though....should I double port the top? One on the top right and one on the top left?

Additional good info and calculators here: http://www.diysubwoofers.org/

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3.4L S/C 87 GT www.fierosound.com
2002/2003/2004 World of Wheels Winner &
Multiple IASCA Stereo Award Winner

Adding a second port will definitely change the sound characteristics of the box. I strongly suggest going to the website linked above to figure out how to tune the box and port(s), or hit up Mach10 for some more tech advice.

Keep in mind that with ported boxes, the box volume and port diameter/length need to be tuned to match the speaker. Your new speakers may need different sized boxes and/or ports. This is important to look into, because ported boxes can be very picky about tuning.

[This message has been edited by Blacktree (edited 02-12-2007).]

depends on the size and length of the port required.. if only one is quoted then divide that by half and use two ports. I was looking at the box build page and thought how cool it would be to drop port tubes down from the top into the box (putting the inside ports in close prox of the coil) and then either leaving them cut square and expanda foaming around them and shaping them in. Or cutting them flush with the box angle (this I'm not sure about, since you might create port noise and a whistle effect.) I've never seen it done but Im sure someones done it. Eitherway dremel down the ID so there isnt a hard edge or you'll exagerate the port noise.

Careful on porting there. If you cut it in half and call it two, you will raise the frequency of the box. They need to be twice as long (not half) to achieve the same frequency.

but i would just plug the side port and port on the top. something like...

Thanks for all the advice and suggestions. Pluses to those that I haven't given one to. So far it looks like the box above posted by Finally_Mine_86_GT will be the final design but longer with longer ports. If I changed my mind and design a sealed box, which is much more forgiving in design, is there any danger in making it larger than specs and damaging the speaker? What I like about the ported box for this project is I'm weary of having the seat backs too close to the woofer and "choking" the cone and keeping it from breathing.

quote Gokart said: ...is there any danger in making it [sealed box] larger than specs and damaging the speaker?

Nope. The bass will just be a bit deeper... which is a good thing!

(edit for clarity)

[This message has been edited by Blacktree (edited 02-14-2007).]

A sealed box is a LOT more forgiving than a ported box. If you go too big with the box and too small the port, it'll sound bad. A sealed box, you can go a little bigger or a little smaller and it won't hurt a thing.

Wow! I never thought I'd get so much help with these speaker questions, thank-you all so much! After all my porting questions and advice I'm leaning more towards a sealed box now
Thanks again, Marc

Make sure they're good and strong! A friend of mine managed to blow a sealed box to pieces with his sub

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