Modelling cone excursion in a TL sub

BoomieMCT · 9th May 2007, 06:41 AM

I've been reading this article on transmission line enclosures and I think I want to give one a try. I cannot, however, find any information on how to model the cone excursion for a TL enclosure. Are there any rules for this?

I normally use Unibox for my modelling, if that provides any kind of useful tool. Can I approximate this with any of the pre-canned enclosures?

MJL21193 · 10th May 2007, 01:25 AM

Hi.
What driver are you using, and what's it's Xmax? Generally speaking, a TL is not much different from a bass reflex, as far as the drivers excursion is concerned. Modeling with Unibox to check max excursion can be done by matching the box volume and port size.
Martin King developed a simulation model specifically for TL's - this is the most accurate way to model response (and excursion).

BoomieMCT · 10th May 2007, 06:48 AM

I had an extra 8" Dayton DVC lying around from when they were on sale. I used one to make a passive PR sub and for some other experiments. I figured I'd make a TL sub (since I never made one before).

I read King's website. His sheets are no longer free so I figured I'd make a cheap and easy one first and if I liked it, then I'd get his sheets.

planet10 · 10th May 2007, 09:25 AM

Quote:

Originally posted by BoomieMCT
I've been reading this article on transmission line enclosures and I think I want to give one a try.

The 1st line in that article: Editor's Note: This methodolgy is obselete and here for historical purposes.

To model a TL use Martin King's software or at least the tables (they are free). The software will show you excursion (and lots of other stuff)

dave

freddi · 10th May 2007, 04:13 PM

Hi Dave - would Bullock's TLBOXMOD be good nuff for ballpark estimate?

Freddy

BoomieMCT · 10th May 2007, 05:18 PM

Quote:

Originally posted by planet10

To model a TL use Martin King's software or at least the tables (they are free). The software will show you excursion (and lots of other stuff)

dave

Unless they are posted somewhere else, the King sheets are no longer free. That's why I've been looking for another source for information.

planet10 · 10th May 2007, 10:58 PM

Quote:

Originally posted by BoomieMCT

Unless they are posted somewhere else, the King sheets are no longer free. That's why I've been looking for another source for information.

The worksheets cost money (and not very much -- people abused the worksheets when they were free, so Martin was foced to restrict access), the tables are free... http://www.quarter-wave.com/Theory/Alignment_Tables.pdf

dave

MJL21193 · 10th May 2007, 11:00 PM

Below are two plots, first is freq. response of a 90" TL with the line cross section start at 2 x Sd, and the end .5 x Sd. It's unstuffed and shows good bass response. Below that is woofer displacement (excursion).

planet10 · 10th May 2007, 11:01 PM

Quote:

Originally posted by freddi
Hi Dave - would Bullock's TLBOXMOD be good nuff for ballpark estimate?

Freddy

I doubt it.

MJL21193 · 10th May 2007, 11:05 PM

Quote:

Originally posted by planet10

The worksheets cost money (and not very much -- people abused the worksheets when they were free, so Martin was foced to restrict access

Abuse of the worksheets for commercial gain, without compensation to Martin King. Use of the original worksheets (such as I have) for DIY is fine.

9th May 2007, 06:41 AM	#1
BoomieMCT diyAudio Member Join Date: May 2007	Modelling cone excursion in a TL sub I've been reading this article on transmission line enclosures and I think I want to give one a try. I cannot, however, find any information on how to model the cone excursion for a TL enclosure. Are there any rules for this? I normally use Unibox for my modelling, if that provides any kind of useful tool. Can I approximate this with any of the pre-canned enclosures?

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10th May 2007, 01:25 AM	#2
MJL21193 Account disabled at member's request Join Date: Mar 2007	Hi. What driver are you using, and what's it's Xmax? Generally speaking, a TL is not much different from a bass reflex, as far as the drivers excursion is concerned. Modeling with Unibox to check max excursion can be done by matching the box volume and port size. Martin King developed a simulation model specifically for TL's - this is the most accurate way to model response (and excursion).

10th May 2007, 06:48 AM	#3
BoomieMCT diyAudio Member Join Date: May 2007	I had an extra 8" Dayton DVC lying around from when they were on sale. I used one to make a passive PR sub and for some other experiments. I figured I'd make a TL sub (since I never made one before). I read King's website. His sheets are no longer free so I figured I'd make a cheap and easy one first and if I liked it, then I'd get his sheets.

10th May 2007, 04:13 PM	#5
freddi diyAudio Member Join Date: Aug 2005	Hi Dave - would Bullock's TLBOXMOD be good nuff for ballpark estimate? Freddy

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