Help with t line box design

[Triticum Agricolam]

Port should be same size or as close to as Possiable the cone area.....

Not smaller than the driver

A tad smaller for better sq

Where did you get you info.....

I got my info from my own experience and from the experience of lots of other people. T-lines aren't just used for car audio subs, they used all over the place. Here is one I built for my home theater:

From the front it looks like a regular ported box, but on the inside:

Its a tapered T-line, the mouth has much less area than the cone does. When you taper a t-line down towards the mouth, it tunes it lower, which saves space, and it also evens out the frequency response. This does come at a cost though, it lowers the efficiency somewhat. Its very similar to what happens when you decrease the net volume on a ported sub, your output gets less peaky, but there is some loss of efficiency.

Preach on sir. In your opinion, in what case is a T-line more appropriate than a ported enclosure since you're saying that a regular ported box can be made with similar efficiency and bandwidth.

I'm not here to preach, and I hope I don't come across that way, I'm just trying to share what I have learned. As far as which situation T-lines are better it really depends on the sub and what your goals are. Its like saying when is a 6th order bandpass better than a 4th order bandpass or a regular ported box? Some subs do well in T-lines, others don't.

As far as similar efficiency and bandwidth go, I'll use the sub I built as an example.

Here is that sub as it was designed in Hornresp (software specifically made to model t-line, horns, ported boxes, etc).

Here is the same sub in a 3.5 cubic foot box tuned to 22 Hz. Both boxes take up almost exactly the same volume.

If you look at the response between 10 and 150 Hz, its virtually identical.

[philrab]

Triticum, you didn't come across as preachy, just knowledgeable. T-lines are something I'm interested in and trying to learn, but because they're less common than other types of enclosures (for car audio at least) there seams to be less knowledge, hence I'm absorbing what I can.

[Triticum Agricolam]

I'm glad I can share what I know, hopefully it's helpful. While I think I have a decent working knowledge of T-lines, I'm certainly not an expert on them. In the hifi home audio world there are a handful designers who have t-lines down to an absolute art. That's where I first learned about them. In that application they are trying to wring every last bit of sound quality out of their designs. It's a lot different application than the car audio world but the science is the same. Fortunately some of tools the hifi world have created are very useful for car audio too, like Hornresp.

[KenSchoen]

Port should be same size or as close to as Possiable the cone area.....

Not smaller than the driver

A tad smaller for better sq

Where did you get you info.....

This is what I've always seen and been told by others. And yes I miss used the word port. I have a bad habbit...if there's a hole in a box with a speaker and air comes out...it's a port lol.

[KenSchoen]

I'm glad I can share what I know, hopefully it's helpful. While I think I have a decent working knowledge of T-lines, I'm certainly not an expert on them. In the hifi home audio world there are a handful designers who have t-lines down to an absolute art. That's where I first learned about them. In that application they are trying to wring every last bit of sound quality out of their designs. It's a lot different application than the car audio world but the science is the same. Fortunately some of tools the hifi world have created are very useful for car audio too, like Hornresp.

Sorry for two posts...I currently own a set of T-line towers. They sound great and I'm doing what I can to tackle their finer points at the moment. Triticum can I PM you about T-line's?

[CortezDTV]

Unless is opposite like above the tapered horn, which can go both way, mostly people make them the opposite way