Quarter Wave / T-Line tutorial-UPDATED

[nCOMP1337]

im working on a design right now for a t-line, just sketching it out, gonna try to work it out with sketchUp program so i can see it in 3D, but im having trouble, because im trying to fit 3 10s into a small space, i dont have to, but i want to try and see if i can work it out or what it would take to work it out, at the worst ill have to fall back to two 10s, i cant have just 1, as my OCD with evenness and symmetry will bother me forever, lol

i understand the problem with having a sub fire directly into a port and then the other not doing so, but the way i have my current design, each sub will technically be same distance from the port, now my trouble is its hard to do this and have the proper space because for 3 subs i have it with 2 ports that are identical and symmetrical to each other

i am guessing that with having two ports it would have to be twice as large as i would normally have for just one port, and then since i am trying to put 3 subs in it, i would have to make up port for the third, basically the third would i think essentially be half firing into each port, however the way the ports are lined, each sub is basically same distance from port, but i assume the middle sub would have a splitting effect when it fires, since its right in the middle

ill try to get a top view sketch i did on graph paper scanned in tomorrow, so you get the idea, im guessing it will be impossible or near impossible to fit the setup in my car, but no harm in trying, while still in the design process

available trunk space max height to actually fit in trunk is 16.5 inches, however i do not want it to be higher than 16, and where the subs are at i plan to have only 12 inches high and then right behind subs when mounting depth is cleared the box will go to 16 inches tall to help with having proper port area. i could do a bit of cutting in my car, but i want to try this without having to modify it much

so basically 16 tall x 38 long x 24 wide

i do not have the subs i will use yet, but im hoping i can get a design that may work and then i can edit it to fit perfect for the subs

i think if i need to make the port shorter i can possibly do a 1/8 wave instead of 1/4 but not sure

the subs will be 10s and together will be at or around 2k rms not sure if series or parallel would be better though, amp is stable to 1ohm at 1200 rms, want to have room to upgrade with the amp when funds are available

any input is appreciated and ill get a sketch up soon

EDIT: Here is the sketch, I drew it in Photoshop, it will help explain my rant above

Also there would be a 45 angle in every corner where possible, i actually just forget them, the beginning of the ports are also 45s

since I dont know the actual specs for the subs since i dont have the subs yet, I went with the specs for a 10 that was liste din the first post, just so i can get an idea

so is this build possible, too small, too big?

[JMZNeal]

So I've been reading the reviews and I may experiment with one if it would sound right on a set of T1 12 d4. Right now I have them on a T1000.1@1ohm and was thinking about going to a Sundown 2000.1 but this would clearly be cheaper at the expense of 1/2 my bed. which is acceptable since i would have also went to 3 T1's eventually and used it anyway.

Size 12"

Impedance 4-Ohm x 2

Power Handling 600 Watts RMS

1200 Watts Max

Voice Coil Diameter 3" anodized aluminum

Motor Size 124 oz. double stacked

Speaker Connector Dual 8 AWG slot load

Fs (Hz) 33

Re (Ohms) 6.2

Le (mH) 4.2

Qms 4.46

Qes 0.63

Qts 0.55

Vas (Liters) 34.8

Sd (cm2) 460

SPL (1w/1m) 86 dB

Xmax (mm) 14

Woofer Displacement 0.08 cu. ft.

(2.26 Liters)

Cutout Diameter 10.8125 in.

(27.46 cm)

Mounting Depth 6.625 in.

(16.83 cm)

Shipping Weight 30.6 Lbs.

(13.9 Kg.)

Do you think it would sound good? Boost is 0-18db@45hz. I use my knob a lot(up to 3/4) between song depending on genre and run flat at my head. And also I have a 360.2. Been too damn long since it's been hooked up i forget i have it. just having it gives me +3 db. i was at about 144ish depending on song. my current box is tuned at 45hz so i may not be able to get better than ported at 45hz spl wise.

So which do ya'll think would have the best over all sound and put me at the 150 Range. 3 T1's off a Sundown 2000.1 or a T-line with 2 T1's and the T1000.1? Also my boot is exposed and it flexes and so does the back wall. So just making a solid tunnel out of .75 and make a .75 back wall solid which would give me a db or two. Plus the new wires and extra alt is sitting me at 14.0v during play 14.5v max. 13.7ish during long hard notes from before 13.0 max 11.7 during hard notes. So that's more too. Hell I may be able to get 148+ out of what I have. I haven't metered it since 07 and am wanting the next time to read 150.

The T'line is a def for my 4" and 3.5" that are in my house.

How do you calculate the net box volume your going to use? Seems like ppl aren't even calculating it at all? Did i miss that some where?

[JMZNeal]

I was thinking about making a Tapped Horn at 55hz. or what ever the Fs of the sub is when I find the manual. I was going to build it straight no bends, and invert the driver into a sealed chamber at the other end. Impractical I know but i want it to sound right the first time and i can stand it straight up in the corner and it would take up like 36sq" of floor space.

I'm desperately trying to find the fs of it so i can solidify my drawing specs and start the build. I hope it's lower but i'm thinking higher. as long as the main guide is less than 8' i can do it easily.

[HellionDarklord]

Would not rounding anything off make a tline sound better if it were being used as s home theater sub?

[HellionDarklord]

Quote:

I'm desperately trying to find the fs of it so i can solidify my drawing specs and start the build. I hope it's

lower but i'm thinking higher. as long as the main guide is less than 8' i can do it easily.

HD:

Try this, you need a resistor that will withstand 5 or 6 watts, a multimeter, a tone generating program for your computer,(or an expensive piece of single purpose equipment) and an amplifier. The resistor goes between the positive speaker output and the positive post on the driver. The positive multimeter lead goes closest to the amp before the resistor on the positive amp output. (I don't remember what ohm resistor, or if it makes a difference.) When the tone generator sweeps through the resonant frequency the voltage drops. I don't remember if putting the negative lead from the multimeter at a ground point or on the negative driver post is better, but I don't think it will mess anything up if you got that part wrong. Hopefully someone on here knows for certain.

Hope that helps!

HD

[HellionDarklord]

invert the driver into a sealed chamber at the other end.

I don't know what that would do for sure, but maybe it would make it like a bandpass enclosure. The problem with most bandpass enclosures is that they have a tiny frequency range. A tline might solve that little problem nicely!

If all else fails,

TRY IT!

Then if at first you don't succeed...

YOU FAIL!!!

HD!

[JMZNeal]

lol. okay so band pass on the T-line not happening. I'm still guessing the FS is high since it's only a 4" driver. the box it was in seamed to be ported about 55hz i think. I can always shorten it if it sounds bad and is to low right. a fail is only preparing you for the win, and if you don't fail then you don't know what it takes to win.

I've also go a design for an 8 at 40hz with a single fold. I'm really stoked about knowing the concept of designing them. Now i just have to practice.

I want the 6ft. long horn as a prototype to show ppl that the concept is. Should i even try to tapper it or just leave it straight? I really want SPL out of it for a little wow affect cuz i want to build t-lines for ppl on a reg basis one day. i'll post pics but vids suck on my phone and the GF has my camera.

[elastic]

where do i find a calculator for the tline box?

[KIRK_ADAMS]

Has anyone tried a single T212D2 in a TLine...?

[JMZNeal]

where do i find a calculator for the tline box?

read post 1 of this thread.

it's calc by 1/4 length of the wave your tuning to

so 1130ft per sec / Fs of sub / 4 (to make it 1/4) =ft of port lenght (div by 12 to get inches)

port area = SD(conearea) of sub so there's 0 back pressure.

round your corners so you don't create a standing wave.

no net volume to calc just port. easiest boxes to make if you know the FS of sub.

bass boost on amp can be a bitch though if it's used alot and is diff than Fs of sub. That's why I'm leaving my T1's in a ported 45hz box cuz the boost on the amp is at 45hz also, and Fs is 33.