TL sweetspots

Tuukka · 22nd May 2006, 01:31 AM

I've been designing a couple sets of TL's. One set is built and I'm in the process of tweaking it with stuffing, and I've started the carpentry on another set. I used the rule of matching 1/4 wave tuning frequency to the resonance of a driver in a sealed enclosure of the same volume as the TL.

To find a reasonable tuning frequency and line taper, I used Winisd sealed enclosure simulations to perform calculations. I started with fairly low box volumes, about 1/2 Vas. Then increased the volume gradually, linearly and the Fsc ofcourse decreased, quite rapidly at first. I noticed that the rate of decrease in Fsc values lessened as well, maybe logarithmically with respect to the increase in enclosure volume. At about 2x Vas, there was already very slight decrease in Fsc.

Could there be an ideal ratio of the Vas of a driver to TL volume, a sort of sweet spot?

Scottmoose · 22nd May 2006, 07:45 AM

Time for some reading:
Martin King's site: www.quarter-wave.com

Read his 'Anatomy of a Transmission Line' article, then his 'Classic TL alignment tables'. Afterward, you might wish to download his seminal MathCad worksheets.

This is not just another set of rules of thumb. They're not rules of thumb at all. Martin is the man who's comprehensively cracked the alleged mysteries of the TL. You want to design one? This is how you do it.

A word of warning. There is heavy math involved on this site. However, don't become discouraged if you can't cope with it all. The important thing to remember is that Martin's done it all for you. All you really need to do is select the appropriate values from the tables, though it's worth persevering with the theoretical side if you can. It's well worth it, because you will then have a thorough understanding of the principles, and it might even encourage you to download the worksheets.

Regards
Scott

qi · 22nd May 2006, 07:59 AM

Read this first. It is a jump-start...

http://www.t-linespeakers.org/design...ies/index.html

Sure hope this helps...

lndm · 22nd May 2006, 01:43 PM

Does anyone know of the Augspurger articles in AudioXpress? These would appeal to many TL designers IMO and are very easy to understand. Are they available on the www? Would it be acceptable to post scans?

Scottmoose · 22nd May 2006, 01:57 PM

Probably not (acceptable to post scans). Augsperger's tables are also a bit dodgy in terms of the quanities of stuffing they suggest, i.e far too much. Martin's are considerably more accurate.

22nd May 2006, 01:31 AM	#1
Tuukka diyAudio Member Join Date: Oct 2002 Location: Suomi	TL sweetspots I've been designing a couple sets of TL's. One set is built and I'm in the process of tweaking it with stuffing, and I've started the carpentry on another set. I used the rule of matching 1/4 wave tuning frequency to the resonance of a driver in a sealed enclosure of the same volume as the TL. To find a reasonable tuning frequency and line taper, I used Winisd sealed enclosure simulations to perform calculations. I started with fairly low box volumes, about 1/2 Vas. Then increased the volume gradually, linearly and the Fsc ofcourse decreased, quite rapidly at first. I noticed that the rate of decrease in Fsc values lessened as well, maybe logarithmically with respect to the increase in enclosure volume. At about 2x Vas, there was already very slight decrease in Fsc. Could there be an ideal ratio of the Vas of a driver to TL volume, a sort of sweet spot?

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22nd May 2006, 07:45 AM	#2
Scottmoose diyAudio Member Join Date: Mar 2005 Location: UK	Time for some reading: Martin King's site: www.quarter-wave.com Read his 'Anatomy of a Transmission Line' article, then his 'Classic TL alignment tables'. Afterward, you might wish to download his seminal MathCad worksheets. This is not just another set of rules of thumb. They're not rules of thumb at all. Martin is the man who's comprehensively cracked the alleged mysteries of the TL. You want to design one? This is how you do it. A word of warning. There is heavy math involved on this site. However, don't become discouraged if you can't cope with it all. The important thing to remember is that Martin's done it all for you. All you really need to do is select the appropriate values from the tables, though it's worth persevering with the theoretical side if you can. It's well worth it, because you will then have a thorough understanding of the principles, and it might even encourage you to download the worksheets. Regards Scott

22nd May 2006, 07:59 AM	#3
qi diyAudio Member Join Date: Oct 2003 Location: .	Read this first. It is a jump-start... http://www.t-linespeakers.org/design...ies/index.html Sure hope this helps...

22nd May 2006, 01:43 PM	#4
lndm diyAudio Member Join Date: Mar 2006 Location: nsw	Does anyone know of the Augspurger articles in AudioXpress? These would appeal to many TL designers IMO and are very easy to understand. Are they available on the www? Would it be acceptable to post scans?

22nd May 2006, 01:57 PM	#5
Scottmoose diyAudio Member Join Date: Mar 2005 Location: UK	Probably not (acceptable to post scans). Augsperger's tables are also a bit dodgy in terms of the quanities of stuffing they suggest, i.e far too much. Martin's are considerably more accurate.

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