Hey everyone first off I'm new to the site so I would like to say hi. Now I have a 2006 impala and I have a fi bl 12 and I had a fully costom box build that is right at 2 cubic feet and is tuned at 33hz potted through the trunk deck. Now the sound is horrible so atomatically I think it's the box but my buddy has the same size box and same size port that was taken out of a mozda rx8 and it's just sitting in the bak of a Mazda b2200 and we put the sub in that box and it freakin pounds. We took his treo out and put in my box and it has good sound. So my question is why in the world does the fi not sound good? I have had it in boxes that load up in the truck and sound amazing but rattel the crap outta the truck so we ported it throught the deck to stop the rattels. Any help or suggestions are appreciated.

Hey everyone first off I'm new to the site so I would like to say hi. Now I have a 2006 impala and I have a fi bl 12 and I had a fully costom box build that is right at 2 cubic feet and is tuned at 33hz potted through the trunk deck. Now the sound is horrible so atomatically I think it's the box but my buddy has the same size box and same size port that was taken out of a mozda rx8 and it's just sitting in the bak of a Mazda b2200 and we put the sub in that box and it freakin pounds. We took his treo out and put in my box and it has good sound. So my question is why in the world does the fi not sound good? I have had it in boxes that load up in the truck and sound amazing but rattel the crap outta the truck so we ported it throught the deck to stop the rattels. Any help or suggestions are appreciated.

What are the settings on the amp and H/U?

Well that's kinda a prob to lol but I have had the sub with the same amp for about three months in a different box and sounded fine but to answer ur question I'm using one of the older xtant amps like a 1001. It claims it's a 1000 watt amp but it gives this bl more than it wants. But the amp does have very many options or a crossover. And I had boomers audio in tulsa set the amp so I donno what it's set at to be honest

Edited December 4, 200915 yr by Ryan Horn

Go out and look at the amp and tell us the settings. It is important.

Is the sub firing forward or backward in your trunk?

Go out and look at the amp and tell us the settings. It is important.

Is the sub firing forward or backward in your trunk?

okay I'll dig the amp out tonight. And it's firing forward and sealed to where there is no pressure in the trunk. I'll take some pictures tonight and post em

Edited December 4, 200915 yr by Ryan Horn

Go out and look at the amp and tell us the settings. It is important.

Is the sub firing forward or backward in your trunk?

okay I'll dig the amp out tonight. And it's firing forward and sealed to where there is no pressure in the trunk. I'll take some pictures tonight and post em

This has been kind of a long night... Did you figure out the problem on your own? Hope the BL is bumpin'!

Go out and look at the amp and tell us the settings. It is important.

Is the sub firing forward or backward in your trunk?

okay I'll dig the amp out tonight. And it's firing forward and sealed to where there is no pressure in the trunk. I'll take some pictures tonight and post em

This has been kind of a long night... Did you figure out the problem on your own? Hope the BL is bumpin'!

haha no still haven't figured it out but I have been busy I got it all taken apart tonight and tomo in the day light I will take some pics but my amp don't have any crossovers or any kinda settings. All it has is a gain. I know that sounds crazy but I'll post a pic tomo to prove it. And settings on the sub on the head unit are normal, 50hz, and that's pretty much it lol. I'm thinking the port is to small. Reason I say this is bc it sounds awesome till the sub gets around half it's excursion. Then port noise takes over... But the box is build at 2 cubic feet and has a 3 inch round port that is 8 inches long I believe.

Your port is way to small.

Yep. Port is waaaaay too small. And what is the 50 hz thing on the head unit? A crossover or a boost? If it's not a crossover, that's a problem. A sub NEEDS a crossover. If it's just a bass boost and you're using it, that's also bad.

Yep. Port is waaaaay too small. And what is the 50 hz thing on the head unit? A crossover or a boost? If it's not a crossover, that's a problem. A sub NEEDS a crossover. If it's just a bass boost and you're using it, that's also bad.

well the port meets the minimal requirements, but if u think it's to small how big should it be? And it's a crossover on te head unit not just a bass boost.

Yep. Port is waaaaay too small. And what is the 50 hz thing on the head unit? A crossover or a boost? If it's not a crossover, that's a problem. A sub NEEDS a crossover. If it's just a bass boost and you're using it, that's also bad.

well the port meets the minimal requirements, but if u think it's to small how big should it be? And it's a crossover on te head unit not just a bass boost.

i dont see how it meets the minimal. you need atleast 24 squar inches of port. i always go on the 16 square per foot on all my boxes, just my prefference. but if you do the math click here it is radius^2 * pi. so yea 7 square isnt enough.

case closed...

Due to port area being way too small, anything else wouldnt really matter at this time.

You need a new box built.

Because the box is 2cuft net, the proper port area would drastically reduce the net volume so a new box is in need.

external port is the only option that allows you to keep that box....

true but man... long port ftl.

Yep. Port is waaaaay too small. And what is the 50 hz thing on the head unit? A crossover or a boost? If it's not a crossover, that's a problem. A sub NEEDS a crossover. If it's just a bass boost and you're using it, that's also bad.

well the port meets the minimal requirements, but if u think it's to small how big should it be? And it's a crossover on te head unit not just a bass boost.

i dont see how it meets the minimal. you need atleast 24 squar inches of port. i always go on the 16 square per foot on all my boxes, just my prefference. but if you do the math click here it is radius^2 * pi. so yea 7 square isnt enough.

okay okay makes sense. Well I was just told that the port was build to spec so I believed it cuz they work at an audio place lol. But the port is already external so I will try and stick with the same box. I will try a different port size and get bak with ya guys. Thanks for the help.

Alright math is not a weak point for me but this is really gettin me. That formula says 7 square inches. I don't see how... Wouldn't the length factor into that formula also? I don't see how I would get the 32sq inches of port if a 3 by 8 port is only 7 lol

you can go get 2 4" round pvc pipes and put them in that gives you 25 square. and its not total volume, its port area. so the opening of your port. if you made a 2d drawing of it and and figured out the area. then thats your port area.

"sq inches" ie two dimensions you multiply that were both in inches

volume is in "cubic inches" ie three dimensions you multiply that were both in inches

This is the external port

the head unit settings

and the only adjustment on the amp

this is my box

build this enclosure for your BL and you will be happy. it does me very well. some things are wrong on the drwing, such as the cubic feet and the tuning. its actually 2.5^3 tuned to 34 hz, with 39 square inches of port. built for a 12" BL

you can go get 2 4" round pvc pipes and put them in that gives you 25 square. and its not total volume, its port area. so the opening of your port. if you made a 2d drawing of it and and figured out the area. then thats your port area.

if I did this... What should the length be? And what difference would length make?

you can go get 2 4" round pvc pipes and put them in that gives you 25 square. and its not total volume, its port area. so the opening of your port. if you made a 2d drawing of it and and figured out the area. then thats your port area.

if I did this... What should the length be? And what difference would length make?

what do you want your tuning at? at 33 hz like you say it is at now. you would need them to be around 30 inches long. but im not sure on that due to the fact that i dont know how to properly calculate dual ported enclosures. maybe some one with some more round port experience can chime in.

just thought of this, if you went out and bought a 6" pvc pipe and put it in at 33 hz it would also need to be around 30 inches long. just one though.

just thought of this, if you went out and bought a 6" pvc pipe and put it in at 33 hz it would also need to be around 30 inches long. just one though.

okay if I did this I can't keep all 30 inches out of the box would it affect sound that much if half was in the box?

Okay I can't even get 30 inches of port so if my max external port was 10 inches and I can go 12 inches inside what would b my best option? Like 4 3 inch ports at 22 inches or what if this won't work I'll just go wit a short six inch to get rid of some port noise... I need opinions here. I am gonna use my curent box regardless and the hz it's tuned is variable right now. I just want to hear what sound this sub is really puttin out cuz it's not loud now...