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Discussion Starter · #1 ·
Long.... but completely out-of-the-box {no pun intended}

http://www.passdiy.com/speakers.htm


These 'Transmission Line" subwoofers (preferably sono-tube style) seem almost too simple, and too good to be true...... Yet, I have been surfing the internet all evening long, looking for simple guidelines, for the optimum diameter and length of the tube to be used, based on sub woofer specs, and I'm just coming up completely empty handed :-(


Anybody here ever put a sub in one end of a tube, and just shake the freaking house down ?


I just have to know more about these !!!


Fish
 

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Discussion Starter · #4 ·
youngho, they did not recommend 24" diameter, 12ft long tubes for every type of transmission line speaker. This is just what they used for a pair of 21" subs to begin with, and then for one 21"er after they overpowered and blew out two of their four subs.

On another site, an audio purist used two 8" subs, with a 12" x 6ft tube. That particular individual didn't even care how loud it was. He just wanted it to be the "sweetest sounding bass he could get..... and in the end, he felt like he found it, with his TL setup.


Steve C, flat to 13 Hz is not low enough for you ??? http://www.passdiy.com/projects/el-pipe-o-8.htm


Come on guys, don't be scared ! ;-)


It's okay to think out of the box sometimes.


Peace,

Fish
 

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Discussion Starter · #6 ·
I was off on a few of the numbers, but that is the one audio purist I mentioned.


Pretty cool, huh ?


I swear I'm fixing to try this with a pair of Titanic 15"s, about 700 wts each, and an 18" tube..... and I don't care if it has to be 14 feet long ;-)


Peace,

Fish
 

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Quote:
Originally Posted by Fish Chris /forum/post/0


Long.... but completely out-of-the-box {no pun intended}

http://www.passdiy.com/speakers.htm


These 'Transmission Line" subwoofers (preferably sono-tube style) seem almost too simple, and too good to be true...... Yet, I have been surfing the internet all evening long, looking for simple guidelines, for the optimum diameter and length of the tube to be used, based on sub woofer specs, and I'm just coming up completely empty handed :-(


Anybody here ever put a sub in one end of a tube, and just shake the freaking house down ?


I just have to know more about these !!!


Fish

Hey Chris.


FYI, El Pipo, in certain Latin countries, i.e. France ("La Pipe") sorta means an oral method of intercourse. So, I guess, that "Out of the Box" may be technically accurate, but morally questionnable.
 

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Discussion Starter · #10 ·
Phillyfisher, nope. The house I live in now is not mine to cut holes in, and I will likely be moving within a few months, most likley to a cabin style home with no attic or basement.

Honestly though, I really like the craziness / brashness factor, of a big ol' imposing tube better anyway :) I've never been one to "hide much of anything" :)


Hey Eagletree... Ha ! Ha ! :) ROTF over here ! Learn something every day, huh ? :)


Fish
 

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Quote:
Originally Posted by Fish Chris /forum/post/0


Yet, I have been surfing the internet all evening long, looking for simple guidelines, for the optimum diameter and length of the tube to be used, based on sub woofer specs, and I'm just coming up completely empty handed :-(


Fish

Transmission line designs are one part science and one part art. Adherence to exact specifications is not as important as with other sealed or ported designs. I've built two TL subs a few years back and love the sound they give me. I get definition and detail from them at a level I've never heard from a retail sub. They go low too.


Find yourself a nice driver designed for a ported enclosure and build to the resonant frequency of the driver.
 

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Discussion Starter · #14 ·
well then you certainly know more than most people do, about TL designs.


I'm still looking at these subs: http://www.partsexpress.com/pe/pshow...number=295-420


So, lets say I was going to use one of these 15"s, strapped straight to the bottom of a tube. What diameter sonotube would you likely start with ? I'm assuming I'd have to buy a whole 12ft or 14ft length of the sonotube, anyway (cheap enough) but how long of a piece do you think I might end up using ?


Next, if I were to use two of these 15" drivers, attached to the bottom like they were with El-Pipo, how would this change things ? They used two 21" drivers with EL-Pipo, with a 24" x 12ft sonotube. So, does an 18" x 9ft tube sound like a decent guess for two 15"s ?


I'm just trying to get some kind of ideas on where to start. Sonotube is cheap anyway.... and I promise I wouldn't blame you BMaugans, if my first (or for that matter, my 9th) attemps failed :)


Heck, if worst came to worst, I could always throw these drivers in a boring old tuned port enclosure. I just hate to follow the crowd though. Y B Norm L ? ;-)


Peace,

Fish
 

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If I understand the article correctly I believe they indicated a 14' pipe resonated at 20hz and a 6' pipe at 40hz. I would imagine intermediate lengths would have sweet spots somewhere in between.


I may give one a try with 10" driver I have laying around doing nothing and an 8' length of tube, just to see.


While we're on the subject of alternative/cheap ways of doing things, I've been considering using my old Pioneer receiver/amp to power a second (this) sub, just running a splitter to it's line levels.


Any major problems with that idea? I wouldn't need to push the amp hard but I'm wondering if there's a significant difference between a regular amp and a sub amp?
 

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Hi Fish,


It's good to see someone on here interested in TL design. Anyone who gave you a hard time about TL design complexity, size, or practicality has probably never heard a TL, or they'd be giving you the thumbs up.


The El-Pipo is a pretty incredible design, but there's certainly no need to go that extreme unless you have drivers that size and music with content down in the 15Hz range.


There are some really good traditional TL design rules available but this budget system won't let me post links, so let's see if we can find a way around it:


speakerbuilding(com)/content/1011/page_7(php)


More cutting edge work is being done by Martin J. king, and a general overview of his work can be found here:


t-linespeakers(org)/design/MJK-for-dummies/index(html)


Martin J. King has a page of his own, but some people find the content to be a little technically heavy:


quarter-wave(com)


Usually the line area is equal to the Sd of the driver at the exit point, and about 1.5-2 times Sd at the end where the driver mounts. In this regard, I would use a 16"-18" diameter pipe for a 15" driver, or a 13"-14" pipe for a 12" driver. Since Sonotube doesn't taper, you'll have to use a straight line, or make a wedge shape of some sort to taper the straight pipe. Either method works very well, although most people tend to prefer the sound of a tapered pipe.


The main problem you'll face is the stuffing material and density. I know 40lbs of Dacron doesn't sound like a lot, but it really is a massive amount of stuffing. Enough to fill a room if you fluff it up. It's also costly when you're buying it in small amounts from the local sewing supply store. Go out and get an idea of the cost of the stuff before you set out. It's expensive enough that it shouldn't be an afterthought.


In all honesty, people complain about the "black magic" of TL design, but it's really not that complicated. Most people are afraid to get out a calculator and a pencil and work out a few things. They want the certainty of a computer program or a suggestion from a website, but trust me, it's better to get a basic grasp on the subject and work it out for yourself. Get the basics down, put the woofer in a pipe that is somewhere around the right length, stuff it, and I know for a fact that the result will sound a whole lot better than a woofer in a ported or sealed box. You can spend the rest of your life messing about with stuffing density, woofer placement, line length and taper, but you'll get 95% of the incredible TL sound just following the basic guidelines.


I'll be building my sixth TL design over the next few weeks, which consists of a Mach 5 Audio MAW-15 in a 16" Sonotube with a piece of wood to taper the line. It'll be tuned to 28Hz-30Hz, and intended primarily for music reproduction. If you're patient enough, I can get it built and report back to you with design info and measurements.


I wish you all the best in your TL adventure. If nothing else, at least give it a shot with a piece of Sonotube and some stuffing. I promise you'll like what you hear!


Regards,

Owen
 
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