First box was a one hit wonder

[Triticum Agricolam]

ok i downloaded the software but do not understand it what so ever.

Its not a program you can just sit down and figure out on your own in 10 minutes. It takes some effort. If you haven't looked over the How To guide I linked above, that would be a good place to start. It will explain what all the different entry fields are and will walk you through some examples.

The first thing you need to know about Hornresp is it is metric system only program To help you out a bit here is what your current ported box looks like in the program. I assumed its 3.9 cubes net at 35 Hz. So the total box is 7.8 cubes (223 liters).

Here is the simulated frequency response:

Looks like you have a pretty good sized peak around 50 Hz, this is pretty typical for a high QTS sub in a ported box. I'm not surprised you aren't real happy with how that sounds.

[Da-Hoe]

You are correct, I'm not happy with the sound and it only sounds decent on higher bass. So basically every song i used to like i can't really hear anymore it feels like 6x9s not 15s

[Triticum Agricolam]

So I entered in your proposed T-line so we can see how it looks, here is how you enter it in:

The S1, S2, & S3 fields are the area of your line (185 sq in = 1193.5 sq cm). The Exp fields are the length. The top one is the distance from the closed end to where your subs will be (I guessed on this one). The next one down is the length from your subs to the end of the line. The total line length is 296 cm or about 117 in. This should tune the line to ~28 Hz.

Here is the resulting frequency response:

The dark line is what the T-line will do, the lighter gray line is what your ported box will do. There isn't much difference at all.

[Triticum Agricolam]

Since you proposed T-line isn't going to improve your situation much at all, lets see what we can do to improve it. We need to get more output from the line, to do that we can increase the line area. Here I increased it to 2000 sq cm, I did this by changing S1, S2, & S3:

This is what it did to the frequency response:

Its a step in the right direction, but we need to bring up the low end some more.

The next thing to try is to move the subs away from the closed end so they are about 1/3 of the way down the line. To do that we increase the first Exp field and decrease the second one:

Here is the result:

This is more what we are after. With cabin gain you should have a nice rising response on the low end and good output.

One problem though. To get this we had to make the box take up about 20 cubic feet of space. Not sure how that's going to work out for you.

[Joe X]

OP I re-read your last thread, this should be your old box:

It's really small and it looks tuned rather high, despite that you expressed no problems with it except you just wanted to upgrade after one sub went out, that's odd as this box should have problems to hit deep bass notes.

I would also recommend to disengage your subsonic filter or set the knob to the lowest frequency for a test, your LPF should be at 70Hz or so.

[Da-Hoe]

Space is not a issue, I have 47w x 38d x however tall. It's a tahoe with no 3rd row. I prefer to use up width and depth as much as possible then go as tall as needed if that makes sense.

Joe x the box pictured was for my 12s the new one I built was skar recommendation for there 15's i purchased, but just didn't sound right.

[Triticum Agricolam]

We can reduce the area of the line down to 1650 sq cm, which is roughly equivalent to your cone area, without reducing performance much. It should save you some space.

One thing that I would like to point out that I don't think many people realize is, we can get the same performance as the t-line out of a ported box as long as it is tuned the same and built to roughly the same size.

In this graph the black line is a ported box, 14 cu ft @ 27 Hz, and the grey line is the T-line. Almost identical performance and the ported box, while still very large, take up less space than the T-line.

You should have enough space for either in your vehicle.

[Da-Hoe]

14 cf ported is larger than what I built maybe that's the issue with this box. If I can get the same performance ported as t line ported would be fine and easier to build. Would the subs be up port back or both facing rear? I think I prefer subs and port back honestly

[Triticum Agricolam]

Having a larger box will bring up the low end, which is what you are looking to do, but it does come at a cost. Besides the fact that it takes up a ton more space, its going to increase cone excursion, which limits your power handling. Assuming those subs actually have the 26.5 mm of xmax Skar is claiming (I'm a little skeptical of that) and you properly set your sub-sonic filter, you should be fine. Having a larger box will also increase group delay, but with the fairly low tune of 27 Hz, that shouldn't be too much of an issue.

As far as whether you have the subs face up or face back, that's up to you. You should be able to take your external dimensions and box specs of 14 cubes @ 27 Hz and plug those into something like Torres and come up with a box design. I'd shoot for about 100 sq in of port area.

[Da-Hoe]

Thank you I will give that a shot.