t line box help

[codyvan87]

Download Sketchup and play with it for a day. You will learn more and knowledge is power. If someone throws you a design and it "doesnt work" then its on them not you. Try try try again and eventually you will be happy with it.

As i stated above, i do not have Internet besides on my phone and sketchup won't install on it. I already tried lol.. I have been told a couple different things so I'm going to take a shot at it without making a design simply because I have no program to make one. But from what I've read I need a 10' line at 11x24 or so. I plan on using rounded corners instead of 45s. I was just curious as if somebody with sketchup would be able to make a design for me. And since my subs are rated at 25hz, would they still sound okay in a box tuned to 30hz?

[codyvan87]

I just built my second t-line yesterday so I'll take a shot at designing one for you. The P3 has a Fs of 26.5 hz but I'll design the box for ~35 hz. Keep in mind this thing will be BIG.

I appreciate the help, but can you design it to be about 30hz? And I know it will be big but it's okay, it's going in an sur so there's plenty of room lol. Just no more than 48" wide..

[MaxVolume]

alright I'm playing with sketchup now between coats of paint on the one i just built haha so far it looks like basic outer dimensions around 48" W x 28" D x 24" H , Subs/Port up on opposite sides of box with 3 folds

[MaxVolume]

going slow since I'm trying to design it the way I would build it (as easy as possible)

here's a first shot, showing the basic layout, box will be turned 90 degrees when finished (sub/port up) but for building the inner walls its easier to do on its side

in this shot there is not top, bottom, or back, so you can get an idea of how the air will flow

[MaxVolume]

After the inner walls and sides are built, the "Top" (actually the front/back) can go on

Now the "back" (bottom) can be attached, and then the "front" (top). The "front" will have the two cutouts for your subs, and the port. The port is 6.75" x 26.5" (same as interior path).

Cutting the port can be tricky, but if you have a router with a flush trim bit you can cut 3 sides of the port to the boxes inner dimensions, then maybe attach a temporary guide to follow for the fourth side of the port (side closest to the subs)

following this path (and allowing for ~7" mounting depth on subs, the wave should have a path of 9.5 to 10 feet, giving you a tuning in the area of 28-30 hz.

pictured here are the "throat blocks" that compress the air entering the port line (picked up from the t-line tutorial and used in both my boxes, which perform well so they may help)

Keep in mind that although they're not shown, 45's in the corners would help that air move, rounding over the edges of the inner walls, and the edges of your port should all help with overall airflow. I always paint the inside of my boxes with resin since mdf tends to "breathe" (grab a couple pieces of mdf, stack them, stick a vaccuum to the top piece, and it will pick up the piece below it as well! at least with 1/2" mdf that my school used)

Anyone and everyone is welcome to weigh in on this, any improvements or suggestions are encouraged as that's the entire point of a forum, combined knowledge coming together to form a better end result (and the chance to win stacks of badass audio gear once a month )

*oh and cut sheet for this design incoming...*

[MaxVolume]

Cut Sheet - 11 Pieces

*ALL CUTS ASSUME USE OF 3/4" MDF. ANYTHING ELSE WILL CHANGE DIMENSIONS AND POSSIBLY RUIN THE DESIGN*

Top : 48" x 28" (contains port/sub cutouts**)

Bottom : 48" x 28"

Front : 48" x 21 3/4"

Back : 48" x 21 3/4"

Side A : 26 1/2" x 21 3/4"

Side B : 26 1/2" x 21 3/4"

Inner Wall A : 26 1/2" x 26 1/2"

Inner Wall B : 26 1/2" x 26 1/2"

Woofer Wall : 15" x 26 1/2"

Throat Block A : 5 3/4" x 26 1/2"

Throat Block B : 5 3/4" x 26 1/2"

** Sub Cutouts = 11 1/4" Diameter Circles

Measure from the bottom/top 7" , then from the side 7"

This should give you the center mark for your circle

Port Cutout = 6 3/4" x 26 1/2"

The woofer wall is 12 1/2" from the side nearest to it

The distance from bottom to first wall, from first wall to second, from second wall to top, is each 6 3/4"

As you can see many of the cuts are in pairs, hopefully making the cutting easier. Many more have the same depth (or height depending on how you look at it). The best way to cut is, as always, with a good table saw and an excellent fence guide. When I build boxes I take many practice cuts to ensure my fence is correct, or at least know how much to offset for perfect cuts. I like to set it to one value, such as your 26 1/2" height/depth, and make ALL the cuts that call for 26 1/2". If you happen to be 1/16" off, at least all the cuts will be uniformly incorrect and hopefully fit together just as well.

And just for fun, one last picture showing the orientation of the box I had in mind, once it is finished being built (with average person for reference of size)

[codyvan87]

Hey thanks I appreciate that. I finally got to a place where I had Internet and was able to get sketchup installed. I tried to make a design and was lost lol.. I'll work with the program a little but I do like that design you gave me..

[MaxVolume]

good to hear you got sketchup, it's a ton of fun once you get the hang of it

quick tips!

hit L to start drawing a line quickly, C for a Circle

if you click to start a line, then move in a particular direction, line changes color to show the axis you're following

while you're doing that (click, drag axis) you can type in a value like 48" , 20' , 1 3/32" etc and the line will be drawn along that path

if you're drawing a circle, the number you type will be the RADIUS instead of the DIAMETER

just have fun try some designs, you can even build the box I designed in the program, using the cut sheet I posted.

[codyvan87]

OK so I figured it out a little bt. Got a design. But now can't figure out any of the dimensions lol..

[MaxVolume]

i usually click one end of a line, and move to the other end of the line, in the bottom right corner it will tell you how long the line is

you can also click the text button on the toolbar, then click a line, by default it should put a marker to show the length