Transmission Line Modelling Software

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#44
schmeet said:
Well eg is the voltage that we are talking about which is derived from sqrt(Power * Resistance). We are discussing what value to take from resistance Re or Znom.

I think I am going to stick with Re as that is what is used by Thiele and Small in their papers.
Click to expand...

We drive speakers with voltage from constant voltage sources AKA amplifiers. Because the impedance of the loudspeaker varies greatly with frequency loudspeakers are generally rated with a nominal impedance. 2v/4Ω=1w 2.83v/8Ω=1w and so on... This makes comparisons of speakers based on nominal power based voltage sensitivity very straight forward. If you were to see the power dissipated by a loudspeaker in real time you would likely be very surprised. What sort of music do you listen to?
 
#45
Just tried version 2.5.1 and compared it to Augspurger's TLwrx. The results were very, very close, likely within expected differences of scaling and rounding off.

Quibbles:
The scale of some of the parameter inputs is odd. MilliHenries is more common, as is liters for Vas.

The 'always on top' behavior of the auxiliary windows is annoying.

The default amp power should probably be one watt. (since I used a rather efficient speaker to test, with 200 watts the system output was literally 'off the chart'! 🙂)


Still, as I say, "quibbles", and you've created an easy to use program with some clever options and abilities that TLwrx lacks. Bravo!
 
#46
NEO Dan said:
Sigh 🙁
Why would you want to base power calculations on Re Pete?
Click to expand...

Hi Dan, mind if I ask are you Dan Wiggins?

I'm sure you know this but I'll just state it so people know where I'm
coming from:
The whole power vs. voltage issues in speaker analysis and
simulation probably bothered me for about 5 years or so, now I'm used
to it. We either use voltage, or we use a voltage stated as power into
some resistive value, that being Re as defined by T&S. I suggest Re
just to be consistent with the papers and the majority of the other
simulators.

The theory is all based on the idea and most common use
where we drive speakers with voltage sources. I believe that the only
use of the actual calculated power in most of these simulators is to
determine if the driver is thermally or excursion limited and using Re is
obviously a gross approximation but thermal ratings are not generally
accurate anyway and I view T&S analysis as mainly for small signal.

There are a few simulators that calculate thermal characteristics in order
to determine thermal compression curves these must use the actual
impedance versus frequency. This was not part of T&S analysis.
 
#50
PB2 said:
Pete, wondering about your resistance/stuffing model, is it constant versus frequency or did you build in any frequency dependency?
Click to expand...
Very good question.


More work for you:

The most common use of modeling programs is to try a design, then tweak it. Some way of comparing two (or more) variations at the same time (short of opening another copy) would be a wonderful thing.
 
#51
I'm comparing to a posted design done in MJKs worksheets and it seems that he
does not include the effect of Le which allows us to see the passband better.
Or perhaps he has a check box for it - I don't remember.
It is simple enough to zero Le, but then the driver parameters are not right.
Some software has a check box to include the effect or not. It is also nice
to note it on the response graph, Le effect included or not.

Thanks for the changes you've made and making this available!
 
#52
Keriwena said:
Just tried version 2.5.1 and compared it to Augspurger's TLwrx. The results were very, very close, likely within expected differences of scaling and rounding off.

Quibbles:
The scale of some of the parameter inputs is odd. MilliHenries is more common, as is liters for Vas.
Click to expand...
First of all, thanks for testing. Good to know it is quite close.
As for the 'scale'. Simple really. I'm an engineer and I always use SI units. It avoids mistakes and confusion. I could make a function to switch between units but that will be far down on my list...

Keriwena said:
The 'always on top' behavior of the auxiliary windows is annoying.
Click to expand...
Yes I agree, I'll change that.

Keriwena said:
The default amp power should probably be one watt. (since I used a rather efficient speaker to test, with 200 watts the system output was literally 'off the chart'! 🙂)
Click to expand...
Again, I agree and its a quick change.

Keriwena said:
Still, as I say, "quibbles", and you've created an easy to use program with some clever options and abilities that TLwrx lacks. Bravo!
Click to expand...
Thanks!
 
#53
Also,

There is no 'new project'. You can just save as and then start a new design. A 'new project' would just reload the default, which is really easy to do, I'll add it.

Undo the last 'update' is possible, I'll give it a shot.

re the stuffing model, I'll explain how it works later but I'm really struggling with that. It seems to be OK at low freq but not at high. I think I need to do it emperically.

A comparison option is possible and I agree would be very useful I'll give it a shot..

Thanks for comments and suggestions guys, keep em coming!
 
#55
Pete, at the moment it works like this:

If you have selected (highlighted) one of the driver library files then click Save, it will save over the file. If you click Save As it will save it to a new file. However if you don't have a file selected then it will just default to Save As.

So it doesn't actually remember what file you actually used it just loads up the driver information.

I think I can make this a bit simpler and more intuitive though...
 
#56
Something like this may be of some use...
Not the exact syntax (cut and paste from some of my code) but could be used for save / save as.

Private mySets AsNewMySettings

PublicFunction Find_Access_Database() AsBoolean
IfNot System.IO.File.Exists(mySets.accdbPath) Then
Dim ofDlog AsNewOpenFileDialog()
ofDlog.Filter = "Access Database Files|*.accdb"
If (ofDlog.ShowDialog() = Windows.Forms.DialogResult.OK) Then
mySets.accdbPath = ofDlog.FileName.ToString
mySets.Save()
Else
MsgBox(" A required database file has not been selected." & vbNewLine & _
" Without it the program can not continue to load." & vbNewLine & _
" The program will now close.", vbCritical, "Missing Database")
ReturnFalse
EndIf
EndIf
ReturnTrue
EndFunction
 
#59
Did the update to 2.6 and I notice when you click on "Save Project" the "Save As" dialog box opens... I realise that it is probably just a cut and paste as a place holder, but just wondering why any dialog box would open instead of just saving.

If you have used the "Open Project" button the file path is known (file path stored or captured after clicking OK button of the "Open dialog box), if you start a new project using the "New Project" button the Save Project option should be greyed out until such time as the Save As option has been used, and then it would be enabled.

If (ofDlog.ShowDialog() = Windows.Forms.DialogResult.OK) Then
mySets.accdbPath = ofDlog.FileName.ToString
mySets.Save()

Ideally you would start with no project loaded and both the Save and Save As options greyed out...
 
#60
Silent Screamer said:
Did the update to 2.6 and I notice when you click on "Save Project" the "Save As" dialog box opens... I realise that it is probably just a cut and paste as a place holder, but just wondering why any dialog box would open instead of just saving.
Click to expand...

If you open the program from scratch and then click save then it will open the Save As dialog because you are not yet working from a file. If you have opened a file and click Save then it will just save to that file.

Silent Screamer said:
if you start a new project using the "New Project" button the Save Project option should be greyed out until such time as the Save As option has been used, and then it would be enabled.
Click to expand...
This is not normal practice. In almost all applications, if you start a new document, the 'Save' option is not greyed out but will just act as a 'Save As' button.

Silent Screamer said:
If (ofDlog.ShowDialog() = Windows.Forms.DialogResult.OK) Then
mySets.accdbPath = ofDlog.FileName.ToString
mySets.Save()
Click to expand...
Thanks. I know how to use Dialog boxes... 😛

Silent Screamer said:
Ideally you would start with no project loaded and both the Save and Save As options greyed out...
Click to expand...
You start with the default project loaded. I don't see an advantage to having nothing loaded, it just means there will be loads of Null errors that need dealing with until the user has entered something into every box.

Again. No application ever has Save or Save As greyed out when you open a new project.
 
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