MJK's 'Classic TL' paper

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
I'm trying to work through this paper, http://www.quarter-wave.com/TLs/Alignment_Tables.pdf ,
a little difficult given my limited maths...
First Question, is 'rho' in the formula at bottom of p3 merely standard air pressure, or is Martin using it to deal with stuffing density (or does he just assume a standard value for stuffing density throughout the paper)?
(I'm not sure which paper is referred to on p2 when he mentions "page 6 of the "Method Derivation" section")

If I understand the paper correctly, then to simplify Martin's 41 pages down to a few lines:D, the design method is as follows:

1: Choose SL/So
2: Lookup Leff, Dz, Dr (Tables pp10-12)
3: Calculate So/Sd (formula bottom p3)
4: Calculate Lactual (formula p14)
5: Choose offset.

How am I going so far?
 
PeteMcK said:
First Question, is 'rho' in the formula at bottom of p3 merely standard air pressure, or is Martin using it to deal with stuffing density (or does he just assume a standard value for stuffing density throughout the paper)?

The rho in the formula at the bottom of page 3 is the density of air, use 1.21 kg/m^3. A standard "constant" in acoustics is the expression (rho x c) where rho is the density of air and c is the speed of sound.


(I'm not sure which paper is referred to on p2 when he mentions "page 6 of the "Method Derivation" section")

That would be the following document.

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


If I understand the paper correctly, then to simplify Martin's 41 pages down to a few lines:D, the design method is as follows:

1: Choose SL/So
2: Lookup Leff, Dz, Dr (Tables pp10-12)
3: Calculate So/Sd (formula bottom p3)
4: Calculate Lactual (formula p14)
5: Choose offset.

How am I going so far?

I think you have it correct. If you follow the sample problem on page 13 and 14 those are the steps.

Hope that helps,
 
Intermediate Q values

attached is Martin's table3 in Graph form; the relationship isn't linear, but should be close enough for intermediate values of Qtd and Dz?
 

Attachments

  • tl intermediate qs.jpg
    tl intermediate qs.jpg
    76.6 KB · Views: 289
Classic TL calculations spreadsheet

I've created a simple spreadsheet which make the calculations from Martin's paper easier. It still requires the user to use the lookup tables.

Apparently I can't attach an Excel spreadsheet here :xeye: ...
If anyone wants a copy send me an email
petermckelvie at optusnet dot com dot au
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.