Port Area for X-12's

[mrd6]

Did I say they're the answer to every box building scenario?

As most people understand, box building is a series of trade offs.... especially in the limited space we have in car audio. So if the recommended port is too large, you can reduce the size.

How much can you reduce the size? Ask that question in a civil manner and someone will probably answer you. ;-)

That all im saying, people keep recommending those calculators, but give no additional explanation to help the OP. In reality, the "recommended" port area is almost never feasible or even necessarily the loudest or best sounding for a given scenario.

So in the end, how is it even helpful?

Edited December 26, 2013 by mrd6

[mrd6]

Those metal ports are insane. That one was 19" port for the bandpass box is NUTS.

I think if you're going to go those metal ports, go for twin 5" ports or twin 6" ports. If 5 cubes net and tuning at 32 Hz, only 17" length needed. If the 6" option, they'll need to be quite a bit longer at 25" in length. Two 5" aeros should be enough, twin 6" ports would be where I would go with it.

Right?! They look awesome painted up nicely too.

[bbeljefe]

Did I say they're the answer to every box building scenario?

As most people understand, box building is a series of trade offs.... especially in the limited space we have in car audio. So if the recommended port is too large, you can reduce the size.

How much can you reduce the size? Ask that question in a civil manner and someone will probably answer you. ;-)

That all im saying, people keep recommending those calculators, but give no additional explanation to help the OP. In reality, the "recommended" port area is almost never feasible or even necessarily the loudest or best sounding for a given scenario.

So in the end, how is it even helpful?

I didn't elaborate because I didn't think to because I'm doing other things as well. But asking usually gets a more detailed answer.

And I trust that you've built boxes with the recommended port area and then built the same box with less port area in order to test these calculators and have some evidence for your claim? The reason I ask is that I've had a lot of success using the correct port area, so I'm wondering what sort of scenario you're talking about.

[mrd6]

Did I say they're the answer to every box building scenario?

As most people understand, box building is a series of trade offs.... especially in the limited space we have in car audio. So if the recommended port is too large, you can reduce the size.

How much can you reduce the size? Ask that question in a civil manner and someone will probably answer you. ;-)

That all im saying, people keep recommending those calculators, but give no additional explanation to help the OP. In reality, the "recommended" port area is almost never feasible or even necessarily the loudest or best sounding for a given scenario.

So in the end, how is it even helpful?

I didn't elaborate because I didn't think to because I'm doing other things as well. But asking usually gets a more detailed answer.

And I trust that you've built boxes with the recommended port area and then built the same box with less port area in order to test these calculators and have some evidence for your claim? The reason I ask is that I've had a lot of success using the correct port area, so I'm wondering what sort of scenario you're talking about.

Some times yes. Ive shrank port area before, kept tuning and box volume the same and gained on the meter. But other times, ive had better results with more port area. In my experience it is trial and error, rather than make the port as large as you possibly can as the calculator suggests. That's the part of this whole theory that I have a problem with ya know?

One scenario where this might hold true is where your port requires alot of 180 degree turns to get to proper length with a large port area. In some situations you'll be louder with a straight port with no turns that has less port area.

But, so back to the OPs question...what would you recommend you do port wise using that calculator for his situation?

[bbeljefe]

It isn't a theory. It's a formula based on the parameters of the driver and the design goal of accurate music reproduction.

As for what I would do, I don't have enough information about the install or the OP's goals to say for sure but one thing I would certainly do is make the port(s) as large as possible.

[Afficionado]

Those metal ports are insane. That one was 19" port for the bandpass box is NUTS.

I think if you're going to go those metal ports, go for twin 5" ports or twin 6" ports. If 5 cubes net and tuning at 32 Hz, only 17" length needed. If the 6" option, they'll need to be quite a bit longer at 25" in length. Two 5" aeros should be enough, twin 6" ports would be where I would go with it.

Is there a reason you'd choose two smaller ports over one bigger port? It would actually be harder for me to fit two smaller ports in my box.

[CleanSierra]

Id choose the two 6" port option for(usually) ease of tuning and not needing such a damn long port.

I actually just looked it up. For the 9" port, in 5 cubes net, tuned to 32 Hz, you'd need it to be just at 27"

That's actually pretty comparable to the length on the two 6" options. If the 9"er is easier for this specific build, let er rip man. Should be really cool looking and since its metal, paint is easy

Edited December 26, 2013 by CleanSierra

[Afficionado]

Id choose the two 6" port option for(usually) ease of running and not needing such a damn long port.

I actually just looked it up. For the 9" port, in 5 cubes net, tuned to 32 Hz, you'd need it to be just at 27"

That's actually pretty comparable to the length on the two 6" options. If the 9"er is easier for this specific build, let er rip man. Should be really cool looking and since its metal, paint is easy

Amen. I'm going to have the box be sealed, but still be pushed into the trunk a bit, so i should be able to have the port sticking outside of the box and still be able to have the back seat on if i want it.

[1clio6]

in my current box, my 6 Xs where seeing 2.3cuft each . the port area for the box is 8sqin per cuft . between 5 - 5.5kw of power rated (not clamped) , in a no-wall build, last termlab session, I was doing 151.8db at 20hz and 154db at 34hz. so yes, small ports do work for these subs aswell as big ports, it depends what you are looking for in your system. flat response = smaller port, higher peak = bigger port. simples