Phoenix Gold Phorum

Well I posted on here about 4 months ago for this project but wound up with money issues. Well money issues are still around but I plan on starting the build in the next month. But I need to get the plans put on paper so I know what I'm doing. This is where I need some help. These are my thoughts so far.

I want to build a single SQL box with three seperate slot ported chambers (one per sub). The entire box will be built using 2 layers of 3/4" birch or maple plywood. So I will have 1.5" walls all around and between each sub. My only limitation is 46" of width. That's all I know about the future box build.

What I don't know is what amount of airspace I need to use? What length of port (or is it square inches)? And how do I measeure the length or square inches?

I'm sure you're wondering what type of vehicle this is going into. Well it will be in the back of an '02 GMC Envoy. Also they will be firing in an upward direction at around a 30 degree angle towards the back of the vehicle. So the box will not be a perfect rectangle it will be more of a four sided wedge.

And for power I will be adding 3 or 4 Optima Yellow Top Batteries. Each Sub will be powered by a single Tantrum T1200.1 all connected to a Tantrum Powergrid.

Alright guys I need as much help as possible. I've never built a ported box. Thanks for your help in advance.

Weren't the Tantrum Powergrids a fire hazard?

Just don't wanna see your stuff go up in smoke.

Not sure if it is or not. First I've heard of it. Only had one problem with it and that was one of the individual caps popped. I sent it into PG when Tad was working there and they sent me back a new one at no charge.

Here's a link to an earlier thread about the powergrid

http://phoenixphorum.com/10-farad-power ... =powergrid

Like I say, I don't have experience with them one way or another, just don't want the fire dept to have to make a house call.

I've never used TI elite subs, but the owner's manual should have box designs and I bet they'll reference circular ports. I've always built to owner's manual specifications. If it were me, I would use circular ports considering your box design.

V(circular port)=pi*r^2*h ("h" being the length of the port)
V(rectangular port)=l*w*h

Calculate the volume of the circular port (length and radius will be given in the owner's manual) and then you should be able to determine the dimensions for a rectangular port. Just keep in mind that the length of the port will determine the tuning frequency of your box. That's something you'll have to determine. Longer=lower.

Go to the "how to" section and Bfowler has some good info. on box building.

which is better slot port or round port?

culzero wrote:which is better slot port or round port?

i really think this is just a matter of personal prefrence

If I use a round port will this give me the smallest physical box?

if you look at the actuall ratio of the opening the round port will give you less resitance since there is no corners

also the opening is even, a slot port depending on your ratio will constrict air. i usaully use a 1 to nine ratio for a slot port or less

the reason slot ports are more common now is because you can intergrate it into the enclosure easier especially if you want alot of port area. and second it can be used as a brace depending on how you apply it.

thanks for all the input guys. But now I have been thinking about this alot, and I am worried about the amps. I would love to use the T1200.1 but I am worried about the chip that everyone says eventually fails.

So for three Ti12dElites what amps would you guys use to drive them?

It's not so much that "it eventually fails" its just that when someone does blow the amp, that's the weak point that goes. if you use it fairly responsibly, it should last you for many years

My T1200.1 still rockzors.

well i guess the reason why i brought it up is because the power output of the amplifiers i have fluctuate on a volume scale there are days when i get in the car and i turn the volume up to 25 and it is blowin me out the car and then the next day i turn it up to 38 and its no where near the same output (this is with all the settings exactly the same the only thing different is that its a different day)

any explanations

brenzbmr@sb wrote:if you look at the actuall ratio of the opening the round port will give you less resitance since there is no corners

also the opening is even, a slot port depending on your ratio will constrict air. i usaully use a 1 to nine ratio for a slot port or less

the reason slot ports are more common now is because you can intergrate it into the enclosure easier especially if you want alot of port area. and second it can be used as a brace depending on how you apply it.

what do you mean by a 1 to 9 ratio? what are you comparing?

in other words keep your vent opening to a 1 to 9 ratio

1 inch by 9 inch

2 inches by 18 inches

3 inches by 27 inches

that was a standard but i usuaally dont use that, ill use a 2 by 10 ratio

do you think 2 x 13 would work or is that to small of an opening

also how do I determine the required port length for the desired tuning frequency

2 by 13 is kinda alright.

it will work.

the length can be detemined by knwing the box volume after port displacement and woofer,

and what frq you wanna tune it at.

well i was hoping to build about a 2.5cuft net after port and woofer displacement and tuned at around 29Hz Hoping to make a SQL box