T-Line box with a sealed side?

[Chris Hammer]

WOW...now my minds like dafuq did i just read. Imma re read this a few times but I think I get what your saying. Thanks for the in depth explanations and help. Its greatly appreciated.

[CortezDTV]

worlds loudest cars are all 4th orders....

[OrangeJuiced]

How about a standard ported front section? like 6th order, not a dual t-line.

[STEvil]

What about a tline on each side? Haha just wondering what that would do

Running the same length on each side would not work as you'd be effectively cancelling out the 1/4 wave effect (both waves would be inverted 1/4 so they'd still be out of phase). Running different lengths could, however help as long as they're at different frequencies/lengths. Unfortunately designing this in a folded T-Line would be extremely difficult.

Would that in essence make it peak at different frequencies? Like making one side at say 35hz and the other side longer or shorter like 25 or 45....I just throw my boxes on top of my back seatsso room isn't a big deal....I think the hardest part would be designing a removeable section so you can remove the sub unless you just leave it in.

You would have to tune one side to a pretty different frequency. Think about it this way, say you've got a T-Line tuned to 35hz, it's 8ft long. Now you add one tuned to 40hz to the other side, and it's 7.5ft long. This would in turn make the 8ft section act like it's only .5ft long, hence pretty much messing up the T-Line.

the only way you could make this work is if you were tuning on a broader range where you could keep one side vastly shorter than the other in some way shape or form...for example, if you wanted to have it tuned to 35hz (say a standard one needs to be 8ft long for 35hz) and then a higher frequency (standard) 1ft long (not sure what this would tune to off the top of my head). You'd need the low tuned side 9ft long and the front side would be 1ft. The issue in design you'd run into is that you'd be limited to only certain ratios since the sound wave coming out of the longer side would need to exit the line at a complete 360 degree of where it originated. I.E. the long side line lenth would need to be 8 times as long as the standard TLine length for a the tuning frequency of the short side's line. It may be possible to only need to be 4x as long but i'm not sure how that would work.

It may be possible to bring the tuning frequencies closer together but I'm not sure how well that would work. Theoretically it would provide the same benefits of running a standard t-line except at two different pass-bands/frequencies. Basically I would say, without knowing the ins and outs of single T-Line theory, it'd be very difficult to even begin to design a functional dual T-Line bandpass enclosure. I've never done the math, and I could be completely off base on the dual T-Line theory, but I beleive it is possible as i've seen people move woofers into the t-line before. And honestly it's really not techically dual T-Lines, it's still a single but the driver is just moved to a position within it.

I think this is generally done in T-line to cut down resonant frequencies at higher frequencies (there are port resonances that come up at certain multiples (higher frequencies) of the main tuning frequency...when the length coresponds with 1/2 wave of a higher frequency, 3/4wave, etc.

Also, here's a link to Martin King's site that I was referencing earlier in the thread: http://www.quarter-wave.com/

7.5ft on one side and 8ft on the other would not make one side seem like it was only .5 feet long.

That said, if you are going to "mix and match" t-lines its better to do 1/4 wave on one side and 1/2 wave or full wave on the other..