another ? about tline.

[mike-g]

So I planned my tline out ,cross section is 6*13,78sq were the sub mounts I need 8 1\4 depth so I was going to start 8" w and taper to 4"w by the first turn but its kinda complicated that way. I ended up doing 8*13 the first 25" until the first turnturn, then dropping back to 6*13 throughout the first turn and the other 84". Will that have ill effects anyone ever do this?I could reverse mount the 12" but was hoping to save some trunk space.what kind of effects does this have on performance when reverse mounted,do i have to wire the 1-12" different or put the headunit on reverse for the sub.I've only made the outside diameter cut and laid out the line.please lmk what you think. I'm building tomorrow. Thank you

[Triticum Agricolam]

So, if you are looking to build space, build a regular ported box and don't build a T-line. Seriously, a t-line has nothing to offer you that you can't do with a regular ported box. Now if you are looking to build a T-line because you want to experiment, well then by all means, have at it.

If you make your first section of the t-line deeper and then thin it down for the rest it probably will have some effect on the output, but I can't tell you exactly what it will be. If you would like to know for sure there is software that can model the output of T-lines, one such piece of software is Hornresp. I can probably model it in Hornresp for you if you would like.

[mike-g]

If you could model what I laid out,8*13 for the first 25". And 6*13 through the first turn and 84" ,total length 109". If just went ported with the sub specs from my other t line ? How does 3cuft net tunned to ?subs fs is 27hz please and thanks

I'm going to download hornresp and try modeling as well but not sure if I'll understand it

[LT.Smoke]

So, if you are looking to build space, build a regular ported box and don't build a T-line. Seriously, a t-line has nothing to offer you that you can't do with a regular ported box. Now if you are looking to build a T-line because you want to experiment, well then by all means, have at it.

If you make your first section of the t-line deeper and then thin it down for the rest it probably will have some effect on the output, but I can't tell you exactly what it will be. If you would like to know for sure there is software that can model the output of T-lines, one such piece of software is Hornresp. I can probably model it in Hornresp for you if you would like.

I disagree with this. T-lines are WAY more efficient than standard ported boxes thus they don't require as much power to be loud and sound good... They command more respect because they offer almost no mechanical control and it is left up to the sub completely because there is almost no backpressure inside a T-line... But for low power-Great output T-lines shine

[mike-g]

I'm modeling the line i made ,your builder, designer told me what to do but when I went to lay it out I was drinking and seemed to complicated to angle,tapper the line and built the rest of the line slanted

[Triticum Agricolam]

I disagree with this. T-lines are WAY more efficient than standard ported boxes thus they don't require as much power to be loud and sound good... They command more respect because they offer almost no mechanical control and it is left up to the sub completely because there is almost no backpressure inside a T-line... But for low power-Great output T-lines shine

You know I totally agree with you that T-lines can be very efficient. However, my experience has been that the efficiency they have comes from their significantly larger size, and not the fact that they are a T-line. Both ported boxes and T-lines are resonant systems and they do pretty much the same thing, they just accomplish it in a different way. They both delay and amplify the sound wave coming off the back of the cone. If you were to make a ported box roughly the same size as a T-line and tune it to the same frequency you will end up with very similar performance. However the ported box is much more flexible in terms of how its physically laid out and doesn't have the funky spikes and dips in output that you get with a T-line due to line resonances. Due to this, it is my opinion that ported boxes are a better solution 99% of the time.

The one situation where t-lines work better is when you are going to build a really small net volume, low tuned box with lots of port area. Usually this is for a single 8" or single 10" and to get the tuning and port area where you want it to be the port has to be a mile long. This is where the T-line shines since having a long line is a benefit to it instead of a hinderance.

[Triticum Agricolam]

So here is the output from the T-line you had described above:

The black line is the T-line and the grey line is a 3.65 cf box tuned to 28 Hz for comparison. As you can see both boxes peak at the same frequency and output level. The T-line is about 2 db more efficient above tuning, but its also 1/3 bigger than the ported box. You will also notice that the t-line has the characteristic peaks and dips in response that you get from the line resonances. Those peaks and dips can be reduced significantly by mounting the sub away from the end of the line, but it does cost you some efficiency to do this.

Here is a graph of the cone excursion of the two designs:

Its hard to see the grey line (ported box) because its virtually identical to what the T-line does. This shows that t-lines control cone excursion just like ported boxes do, your sub is not operating like its in free air in a t-line box.

ETA: I would like to point out that both the t-line and the ported box have giant spikes in output at tuning and with both probably sound peaky as hell. Not what I would want to listen to, but to each their own.

[mike-g]

I'm trying to model in winisd but don't know what would be good,could you make a recommendation on a good ported enclosure per this sub please

[mike-g]

Thanks for the input by the way

[mike-g]

Like I said I don't know what would sound good from winisd I'm a noob and don't get what all the features do,and what would .make a good enclosure