Simple document for building Transmission Lines?

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enigmaticEntity.

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Joined 2009
#1
I was wondering if it would be worth trying to build TL enclosures for my full ranges (when I get some)?

Could it be as simple as:

- Choosing a (1/4 wave) line length just below Fs;
- Designing a tapered, labyrinth line that fits inside the desired enclosure shape;
- Finding the cross sectional area;
- Having to adjust the line length for stuffing?

Would I be able to do this without going through such detail as I find on most of the websites I look at?

(Sorry, I don't really understand the math, just that the 1/4 wave, stuffing and tapered line helps reduce resonance and give lower bass output.)

Otherwise I may have to settle for a stuffed, deadened ported enclosure.
 
#2
Simple answer is NO.

What you have described is classic TL design... http://t-linespeakers.org/design/classic.html

1/ you will get less bass if you tune a tapered or straight TL below Fs.
2/ a line that tapers such that the terminus cross-section is smaller than the start needs to be shortened
3/ damping has no effect on the length of the line (see 2)

You will be much further ahead just plugging a driver into Martin King's free alignment tables (available as a downloadable spreadsheet)

dave
 
#3
Thank you very much. 🙂

Just one question: "put the driver on the side of the line"

Does this mean that when I look at the driver from the front, I can see the folds of the TL (if the "side" of the enclosure was taken off)?
 

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#4
What FullRange drivers are you building an enclosure for? You may wanna see what someone here has figured out for them already. Some FR drivers will perform much better in a certain design and just ok in a simple sealed or OB. Some will not perform much better in a complicated design. Many fantastic enclosures have been designed here for Fostex FR drivers and it is a shame to put them in anything less.
 
#5
If you haven't gotten your speakers yet, the best TL suggestion I can think of is the Alpha TL in the short article of a now dated issue of Speakerbuilder. Someone may know of a place which has it in another format. Measurements are given for the Jordan 92s.

What I was curious about is the mention of tables for Martin King's calculations that you could plug in values for that is downloadable at no cost. Can someone say more about that? I'm aware of Martin's page for subscribers but not the alignment tables.
 
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#11
901Fixer said:
What FullRange drivers are you building an enclosure for? You may wanna see what someone here has figured out for them already. Some FR drivers will perform much better in a certain design and just ok in a simple sealed or OB. Some will not perform much better in a complicated design. Many fantastic enclosures have been designed here for Fostex FR drivers and it is a shame to put them in anything less.
Click to expand...

I was thinking of getting the Creative Sound Solutions fr125sr 4.5'' driver.

I'm a little attracted to the asthetics of the fr125sr more-so than the Fostex FX's (Sigma) at this stage, maybe it's because I like black better than white in speakers. The Fostex does seem to have better Qms and BL, though I'm just a little worried about the Xmax and the frequency response - it seems less flat than the CSS fr. I'll check out some of the designs to see what I think.

I put the values into the tables from Martin's site: (For the fr125)
 

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#14
enigmaticEntity. said:
I was thinking of getting the Creative Sound Solutions fr125sr 4.5'' driver.

I'm a little attracted to the asthetics of the fr125sr more-so than the Fostex FX's (Sigma) at this stage, maybe it's because I like black better than white in speakers. The Fostex does seem to have better Qms and BL, though I'm just a little worried about the Xmax and the frequency response - it seems less flat than the CSS fr. I'll check out some of the designs to see what I think.

I put the values into the tables from Martin's site: (For the fr125)
Click to expand...



you might want to also consider the CSS EL70 (by Mark Audio)

An externally hosted image should be here but it was not working when we last tested it.



http://www.creativesound.ca/pdf/CSS-EL70-data-080909.pdf

At $90 USD / pair, they are slightly lower cost than FR125, but don't have that sexy copper coloured phase plug.
 
#17
Hi Solve, does it open in your spreadsheet program, or display in the browser? If it displays in the browser, try this instead: right-click on the link and choose "Save Target as" or "Save Link As" and save to your hard drive, then open in your spreadsheet program.
 
#18
Henkjan said:
thanks for the reminder... I'll try to port my excel sheet to open office (anyone some tips on what to replace my VBA functions with in OO?)
Click to expand...

Hi Henkjan, OpenOffice uses a dialect of BASIC which is very similar to VBA. The syntax is the same, but the underlying objects are different, so you have to do a bit of renaming (and some recoding). Just for fun, try a snippet in this converter to quickly see some differences: http://www.business-spreadsheets.com/vba2oo.asp
 
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