Sundown E8 Tline

[fritosaregood 0]

all of that sounds like it would work good, but doesnt the line of a tline have to be either the fs of the driver, or the boost frequency on the amp?

Nothing to do with either.

The length determains the cutoff, that's it...

Read up on Martin Kings (www.quarter-wave.com) white papers, you'll save yourself alot of time and headache.

Additionally, diysubwoofers.org has a short, yet to the point explanation of a T-line.

To be honest, most "T-lines" you see here, or any car audio site for that matter, aren't T-lines at all....

i think youve said this to me before, and ive read most of the things on those sites, and asked questions on here before and thats the answer on line length that i got out of it.

[95Honda 486]

Don't ask questions on a car audio board about 1/4 wave line length....

Table 1 here gives you line length:

http://www.quarter-wave.com/TLs/Alignment_Tables.pdf

Notice driver Fs and bass boost aren't part of it. Seriously, if you are interested in T-lines, read this entire document....

[akjay907 0]

Nice work!

[fritosaregood 0]

i got the building of the box all finished up today, waitin on the carpet for now. I did run in to some problems towards the end though

pics.

time for the plexi glass, this was my first time so it took me about an hour on a scrap piece to get the right holes for the screws.

after all this i tested the boxes and is sounded like i had lots of air leaks. so i had to take the top off and seal things up. tested again, and still sounded like are leaks. so i put in on the floor with the openings on the floor and no sound or air leaks as i tilted it up, it seemed like all the unwanted noise was coming from the back chamber line. my thoughts are maybe not enough space between the back of the sub and the wall. the magnet has about a half inch to play with. also the sub is sort of double baffled( i saw another thread where bigjon was askin a question of whether this would choke the air from the backwave, maybe thats wats happening). here is a vid of how it sounded like that.

http://s369.photobucket.com/albums/oo133/F...nt=MOV07635.flv

I grabbed a book and covered up the the opening of the line for the back of the sub, and it sounded alot better, so i cut some mdf pieces to block off the opening. here is a vid of that.

http://s369.photobucket.com/albums/oo133/F...nt=MOV07636.flv

So now,(P Dizzle, this is for you) i have turned this into a bandpass style box, It gets pretty loud now, but there is still some unwanted noise, so Im goin to flare the ends of the lines and see what that does. Also the sealed chamber is around 1.12 cubes, im thinkin thats another reason for the bad sound. Any recommendations on what volume i should put the sealed chamber at?

[P-Dizzle 1]

You could probably seal it off pretty small. 0.2-0.4 cuft.

Edited December 19, 2008 by P-Dizzle

[fritosaregood 0]

ok. i was thinkin around somethin around .5ish

[95Honda 486]

Were both lines on each side of the woofer the exact same length? If they were, they were cancelling each other within the pass band of the line... I didn't realize until I saw the last pictures what you were actually doing.... You had 2 identical outputs, about 1' from each other 180 degrees out of phase.... Not a good thing for much below 80Hz or so.....

Trying building a straight forward 1/4 wave stuffed line.... Then you will hear what a T-line is supposed to sound like...

You'll lose alot of efficency making a bandpass with a T-line on one side vs. a standard port do to line loss...

[fritosaregood 0]

Were both lines on each side of the woofer the exact same length? If they were, they were cancelling each other within the pass band of the line... I didn't realize until I saw the last pictures what you were actually doing.... You had 2 identical outputs, about 1' from each other 180 degrees out of phase.... Not a good thing for much below 80Hz or so.....

Trying building a straight forward 1/4 wave stuffed line.... Then you will hear what a T-line is supposed to sound like...

You'll lose alot of efficency making a bandpass with a T-line on one side vs. a standard port do to line loss...

it did start to sound alright at higher frequecies, but it it still loud for some 8's with this wierd bandpass tline box(once i blocked off one line).

next up is a regular tline, then a regular ported box for 4 of the 8's.

do you have a recommendation one what my line length should before regular tline?

[95Honda 486]

do you have a recommendation one what my line length should before regular tline?

Read the white paper(s).

30Hz? Shoot for 5-6ft stuffed. Finish at Sd. Start at 1.25x Sd.

That's a T-line...

If you aren't stuffing, it needs to be alot longer than that (A LOT longer), that is why ALL proper T-lines are stuffed....

T-Lines ARE NOT for SPL, there are NOT as efficient as a ported enclosure above resonance....

[fritosaregood 0]

today i took it back apart and blocked of the back chamber at .3cubes it sounds alot better, i put both boxes in my car just now and it sounds great, it's the best 8's ive heard so far.

[P-Dizzle 1]

Cool. When it comes to enclosures everything is based on theory. I have built some crazy chit in my day that never should have worked but turned out great. On the other hand, you can build a box to exact specs with poor results.

Edited December 20, 2008 by P-Dizzle

[aznboi3644 2]

Were both lines on each side of the woofer the exact same length? If they were, they were cancelling each other within the pass band of the line... I didn't realize until I saw the last pictures what you were actually doing.... You had 2 identical outputs, about 1' from each other 180 degrees out of phase.... Not a good thing for much below 80Hz or so.....

Trying building a straight forward 1/4 wave stuffed line.... Then you will hear what a T-line is supposed to sound like...

You'll lose alot of efficency making a bandpass with a T-line on one side vs. a standard port do to line loss...

exactly what I was trying to figure out...basically you are free airing the sub around tuning and output is weak.

What you should have done is have one side tuned low and the other side tuned 1/3 octave higher or so.

Should have done more research.

[fritosaregood 0]

Were both lines on each side of the woofer the exact same length? If they were, they were cancelling each other within the pass band of the line... I didn't realize until I saw the last pictures what you were actually doing.... You had 2 identical outputs, about 1' from each other 180 degrees out of phase.... Not a good thing for much below 80Hz or so.....

Trying building a straight forward 1/4 wave stuffed line.... Then you will hear what a T-line is supposed to sound like...

You'll lose alot of efficency making a bandpass with a T-line on one side vs. a standard port do to line loss...

exactly what I was trying to figure out...basically you are free airing the sub around tuning and output is weak.

What you should have done is have one side tuned low and the other side tuned 1/3 octave higher or so.

Should have done more research.

ive done some research,.. i just wanted to try somethin

[dbjunior 0]

by sealing off the back you have turned it into a 4th order bandpass tline. try shifting the sub over one row in the box like i said earlier you should have a better sound and more output than the 4th order.

[fritosaregood 0]

by sealing off the back you have turned it into a 4th order bandpass tline. try shifting the sub over one row in the box like i said earlier you should have a better sound and more output than the 4th order.

what im going to do is use just one box put the subs on the outside of the sides, the use stuffing to decrease the frequency tune. if that works out good ill try to do one for 4 of the 8's

also ive been playin the guess wat i have in my trunk game, ppl are sayin 2 12's a 1 or 2 15's(i think those ppl didnt know anythin) and 1000 watts... then i say 2 8's 350 watts

[fritosaregood 0]

so i know its been said alot that tlines arent meant for spl, but what about them makes that happen, is it because its basically like having a free air sub

[Echo42987 0]

Very nice so far! Great job!

[fritosaregood 0]

updates.. its not done yet.. i might have time tomorrow to finish. I shrunk it all down to fit in one box.

[dbjunior 0]

should sound a lot better.

[fritosaregood 0]

i did a little test today, is that the right way to stuff the line? It seems like there is hardly any sound.

the sub has about a 3/4" space between the foam because its mounted on the outside of the wood, with the magnet out. should i have more room between the foam or should it be close like that. Also, is this the right thing to stuff with?

[dbjunior 0]

is it the crispy stiff board foam. it should be a soft cotton like foam and id leave the middle one out plus they look a little thick i say a 1/4in to 3/8 cotton or poly cloth like pad stappled to the walls.

[Bigpimpin91 0]

Poly Fill is your friend.

That looks like packaging foam.

[dbjunior 0]

Poly Fill is your friend.

That looks like packaging foam.

cant be regular poly fill though it has to be the batting/padding style or it will be difficult to work wih in this app.

[fritosaregood 0]

its just some craft foam I got from walmart, it says 100% urethane foam, ill try takin out the middle and see wat happens. I also ordered some Acousta-Stuf polyfill from PartsExpress earlier today.

oh and the foam is 3 layers of 1" thick foam. I thought i was suppose to fill the entire area of the line,

[95Honda 486]

its just some craft foam I got from walmart, it says 100% urethane foam, ill try takin out the middle and see wat happens.

Is this a joke? Seriously, you need to read those white papers and go through Martin Kings site before you waste more time or damage your drivers.

They spell everything out. Especially the kind of line dampening to use.

i say a 1/4in to 3/8 cotton or poly cloth like pad stappled to the walls.

This is absolutely NOT how you dampen a T-line...