Quarter Wave / T-Line tutorial-UPDATED

[DHFHades]

ok, I think I'm gonna try to build one of these. for 2 JBL GT512s...yeah I know, they're not all that. but they were cheap and I can't run to much power...only got 60 amps to work with I'm gettin decent volume out of them in a bandpass box, 140db on a test tone. hopefully it'll sound a little better with this box if it even fits in my car that is...lol

[qu1cks1lver56]

so im gettin some p2's in a box from my cousin.

and i want to build a t-line for one of my old p1's.

id like to do it for both but i just dont think i have the room to do it.

ill get some dimensions that i have to work with up in the next couple days if someone wants to help with drawing me up some plans?

[aznboi3644]

Got a hold of some 15s temporarily so I get to use atleast 1 until recone parts come in, so I dusted off, and fumigated for spiders ( 40hz test tones )

And cleaned up my ole Iso loaded bandpass Tline, loaded a sub up in it, and ohh so sweet. This box transforms, so its either a iso bandpass, transmission line, ported, or standard bandpass t-line

Felt good to have some beat playing this low with authority again!!

^^ Ugly white door, I had tossed the old regular MDF door, this will have to do

I built these subs about 3 years ago, I ended up selling them to a friend about a year ago, he loved them so much, he used them as trophy pieces, waiting to find a better sub. He went thru L7s, Type Rs, and a few other subs to name a few, and always went back to these. Couldn't blow them, and couldn't find any subs that sounded better

SO, I'am just reconing these from DVC 4ohm to DVC 1ohm, and adding a 3rd spider, and longer coil winding width

Just thought I'd share

what is the 1/4 wave frequency of your bandpass line?

[raytard]

bumpin, any chance you could critique this for me? i sold my subs and need something in the meantime, i have an unused cerwin vega vega!84 kickin around, gonna throw a random 150wrms amp on it, gonna be put in my armrest hole basically, forward firing

sorry its so shitty, but the specs are there i guess, 3/4in mdf, doubled over port, outside dimensions are 8.5w, 16.25 high, 50 long

so i guess that makes the top part come out to 45inches long, the douwn part is 7 inches, and the bottom is another 45inches, 97inches total, so ~35hz (subs fs), port is going to be 7in by 7in (which i guess is ok for an 8in sub, its back at home si i never rele measured surround to surround)

t/s specs:

Free-Air Resonance: fs 35 Hz

Total Q: Qts 0.323

Mechanical Q: Qms 4.56

Electrical Q: Qes 0.865

Compliance Volume: Vas 0.7 ft 3

Maximum Excursion: Xmax 1.20" (+ 0.60")

30.4 mm (+15.20 mm)

Voice Coil DC Resistance: Revc 3.5 Ω

Volume Displacement: 0.04 ft3

should i tweak this at all (like make the port 7.1x7.1 or something? did i calculate the distance right? any suggestions on bass bost or anything, cuz i know u mention that in the write up, or shud i just mess with it?

[Forevrbumpn]

what is the 1/4 wave frequency of your bandpass line?

I made and designed this box about 3 years ago, and after the 06' season, I got rid of my blazer, and threw it in the garage. I measured it wrong, and thought this whole time it was about 32- 34hz, but after some better calculations, I came to the realization its more towards 36hz

It still plays loud lowly with EASE!

I do have another blue printed project that will fit my Denali from side to side, about 1.5" taller, and about 8" deeper, same design, but a 18" in a 30 hz bandpass t-line. With what I'am seeing at only 350 w/rms now, I cant wait to see this box done and tested. I plan on getting either the Sundown 1200 ( or higher) on it, or try one of the Hellfire's out during tax time

I haven't metered it yet, but with the same sub I have in there now, and 1800rms, I did a 146.## music, and a 148 burp, I think now I' am doing a solid 142-143db at a pretty low frequency

[Forevrbumpn]

bumpin, any chance you could critique this for me? i sold my subs and need something in the meantime, i have an unused cerwin vega vega!84 kickin around, gonna throw a random 150wrms amp on it, gonna be put in my armrest hole basically, forward firing

sorry its so shitty, but the specs are there i guess, 3/4in mdf, doubled over port, outside dimensions are 8.5w, 16.25 high, 50 long

so i guess that makes the top part come out to 45inches long, the douwn part is 7 inches, and the bottom is another 45inches, 97inches total, so ~35hz (subs fs), port is going to be 7in by 7in (which i guess is ok for an 8in sub, its back at home si i never rele measured surround to surround)

t/s specs:

Free-Air Resonance: fs 35 Hz

Total Q: Qts 0.323

Mechanical Q: Qms 4.56

Electrical Q: Qes 0.865

Compliance Volume: Vas 0.7 ft 3

Maximum Excursion: Xmax 1.20" (+ 0.60")

30.4 mm (+15.20 mm)

Voice Coil DC Resistance: Revc 3.5 Ω

Volume Displacement: 0.04 ft3

should i tweak this at all (like make the port 7.1x7.1 or something? did i calculate the distance right? any suggestions on bass bost or anything, cuz i know u mention that in the write up, or shud i just mess with it?

That should make a killer sub for a t-line. Is this one of them old 99'-00' Vega series subs? those were sweeet! I loved them. How are you mounting a 45"+ deep box? or wide box?

[raytard]

50in deep

its sliding through the armrest hole in the back and extending all the way to the back of the trunk, its going to stick out an inch or two, but wtvr=) my trunk is like 43/44 inches and the seat is ~6in thick, and it just so happens the opening is 8.25 inches wide and like 20 high, so all it needs is a 4inch pretty panel on top

and yea, its an older and unused one, 99/00 sounds right, it was a display in the store i work at apparently since they've opened, and that was 99 i believe. i guess noone wanted an open box vega 8in, and we were cleaning and my boss told me 25$, so i took it for a home theater replacement, so this box is prob going in my room off a 150watt plate amp when i go big in the trunk this summer

i just wanted to make sure all my calculations were right before i started cutting wood, the separator at the center is getting rounded off as is the port opening, and probably the whole box, its not going to be around long enough to warrant carpet/paint/covering of any sort, so its staying mdf

[raytard]

yea, so uh, i need a design that will work, i know u said in the chat you'd sketch something for me, but i need like exact dimensions, this is getting built the week after christmas

like i said, port and sub on same side, 8.5x20 is the biggest i can go, may be 8.5x18 or 8.5x17, i havnt taken the back seat out to see where the trunk floor connects yet so idk...somewhere thereabouts

50 is the maximum distance i can get

you said something about tapers or something, if you could figure out that tuning and dimensions and whatnot, even if you just send me a crap ms paint drawing with arrows and numbers like i drew, i'll paypal u 20$ =)

if you want to get exact and want the sd of the driver, i'll post it up tomorrow night when i go home and have the sub in my hands

[BigPimpin91]

For those looking for awesome T-Line subs.

Check Sound Splinter.

Their RL-P series are fucking Crazy.

FS 18.8hz

QMS 2.26

QTS 0.219

And the RL-I's listed in this ad would kill too.

http://www.soundsolutionsaudio.com/forum/i...=18628&st=0

Qts - 0.247

Qms - 2.521

Fs - 18.563 Hz

[Forevrbumpn]

man, I was expecting to see a build log on those