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Old 20th September 2012, 09:54 PM   #51
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As a general rule, if a field in a wizard has one or more unit names below it, you need to specify the unit if you want to use other than the default.

For the case in question:
1. Paste epa's def_bassunit into an Akabak script. Leave the cursor in the data.
2. Select Def_BassUnit (Ctrl-B)
3. Note that the "Mechanical Mass Mms..." field has "47g" in it, and the legend underneath says "kg,g,..."
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Old 21st September 2012, 02:46 AM   #52
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Quote:
Originally Posted by Don Hills View Post
As a general rule, if a field in a wizard has one or more unit names below it, you need to specify the unit if you want to use other than the default.

For the case in question:
1. Paste epa's def_bassunit into an Akabak script. Leave the cursor in the data.
2. Select Def_BassUnit (Ctrl-B)
3. Note that the "Mechanical Mass Mms..." field has "47g" in it, and the legend underneath says "kg,g,..."
Seeing that it specified 'g' as an alternate unit I did write 'g' after the '47'.

At any rate, I am going to try a couple of other drivers tomorrow and see what it does - but at this point it looks flaky to me.

In what other ways does it act flaky?
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Old 21st September 2012, 04:15 AM   #53
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Every time AkAbak has given me "flaky" results it has been because I got lazy and forgot to explicitly specify a unit for a parameter. Note that in some of the wizards the input boxes allow you to specify alternate units depending on whether you have Thiele-Small parameters or mechanical parameters. Here is part of an "AkAbak for Dummies" doc I wrote a few years ago:

From the top menu select "Def -> Def_BassUnit...".
A data entry window will open, called "Definition Def_BassUnit / Calculator".

In the top row of boxes, enter the parameters for the driver you are using.
You should have everything except maybe the voice coil inductance.

Note the units choices for some of the boxes.
Akabak allows you to specify your driver in physical values (Mms, Cms, Bl etc) or Thiele-Small values (Qms, Qes, Vas etc), or a mixture of both. Right-button clicking on a box will pop up a list of parameters that Akabak will accept for that field.

For example, the second box from the right may be labelled either "Mechanical Mass (Mms)...", "Equ. vol. to compliance (Vas)...", or "Mechanical Compliance (Cms)...".
You can either change it to the value you have by selecting from the right-click menu, or just enter the value you have with the correct unit suffix. To enter Vas, specify volume units, for example in cubic feet (2.4ft3) or litres (49L). Mms, Vas and Cms have different units of measurement so Akabak will know which value you have entered.

Also, the driver "Diaphragm diameter" (dD) is more commonly specified as "Diaphragm Area" (Sd). You can enter the value as a diameter (for example, 16.5cm) or area (for example, 200cm2).

In the second row of boxes you can enter the Xmax parameter if you have it, and the volume of the enclosure. The rest of the fields can be left as they are.




Check for Typos
---------------
Press the "Evaluate" button at the bottom of the window. If all of the required values have been entered, AkAbak will populate the two rows of values at the bottom left of the window. Values such as "fc", "Qtc", and "f3" should be close to those calculated by your other program.

If the fields do not populate, look to see if the cursor has moved to one of the input fields at the top of the window. The value may be missing (and required), or AkAbak can't understand the entered value.

If the evaluated values are very different than your pre-calculated box, then Akabak has likely misinterpreted one of the input values. For example, AkAbak defaults to "cubic metres" in the "Vb" field. Entering "165" will be interpreted as 165 cubic metres. Specify the unit, for example litres (165L) or cubic feet (6.2ft3).
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Old 21st September 2012, 01:06 PM   #54
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Thanks for your reply Don. Love your tutorial - is in fact what I am using to learn the program.

I was sure I was doing something wrong as I said in post #46, but so far no one has been able to show me what that is.

Even now I am sitting here with the wizard populated and when I write in '47g' it does not accept it, and when I write in .047 it does accept it. All other values the same, paying particular attention to write '47g' as stated in the label below the box.

So I am trying a different driver - the Eminence Deltalite II 2512 - and I am getting the same results. Mms is 49g in this driver, and it will not accept '49g', but accepts '.049' just fine.

Really - no one else has this problem? I mean, I'm not going to cry about it if it's the only bug in the program, but it does seem quirky to me, no matter how you slice it.
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Old 23rd September 2012, 12:52 PM   #55
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Quote:
Originally Posted by LafeEric View Post
... I was sure I was doing something wrong as I said in post #46, but so far no one has been able to show me what that is.
...
Well, I marked and copied the bassunit spec from post #46 and pasted it into a new AkAbak script. I put the cursor in it and pressed Ctrl-B. The wizard came up OK, and pressing "Evaluate" populated the solution boxes at the lower left.
I deleted and typed in "47g" and also tried "0.47". They both evaluated the same. See the attached screenshot and compare it very carefully with your screen.

Edit:
I've just looked carefully myself. Vb should not be zero. Try specifying the enclosure volume.
Attached Images
File Type: png Beyma 12MI100.PNG (32.6 KB, 119 views)

Last edited by Don Hills; 23rd September 2012 at 12:59 PM.
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Old 23rd September 2012, 08:57 PM   #56
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... Oops, it was late at night, for "0.47" read "0.047".
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Old 24th September 2012, 01:26 PM   #57
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Quote:
Originally Posted by Don Hills View Post
... Oops, it was late at night, for "0.47" read "0.047".
I figured.

Stranger and stranger....

Thanks for your investigations Don. I went back and copy/pasted the parameters listed in post 46 into a new script and hit Ctrl-B and sure enough it populated the Bass Unit Wizard with an Mms of "47g", accepting either '47g' or '.047'. Okay.

It is true that I hadn't written a Vb in post 46, however I had been trying it with and without Vb values in trying to get it to work. FYI, I settled on a Vb of 3L for a f3 of 199 Hz. The evaluation problem was there whether or not I entered a Vb.

Strange thing - that value does not work with the script generated in that fashion. With this script, it takes 4L for an f3 of 200 Hz. With a Vb of 3L this script gives an f3 of 214Hz. Also, if I go back to the Def-Bass Unit wizard and enter the values manually, it still will not accept '47g', but does accept '.047'. If I fill the wizard manually, 3L still gives an f3 of 199Hz - with all values appearing the same.

I am considering two possibilities at this point; Perhaps there is something wrong with my installation. Perhaps at some point when I was first playing with the program I screwed up some setting somewhere that is playing havoc with parameter entry. Or, perhaps there is something wrong with these numbers. Even though I got the numbers from WinISD, which is also famously finicky when entering T/S data, there is something about the numbers it just doesn't like, and is able to interpret the numbers somewhat differently depending on how they are entered.

Really though, I have no idea.

Last edited by LafeEric; 24th September 2012 at 01:30 PM.
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Old 24th September 2012, 09:25 PM   #58
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OK, I tried it "manually" and saw the problem. It appears to want the Vas instead of the Mms value. I'll play with it some more in my "copious free time" (ha, ha). It is probably sensitive to the order in which the parameters are entered. It only occurs on manual entry, I found that if I do a def_driver and then do a def_bassunit with the cursor in the driver parameters it also works OK.

I doubt it will ever be fixed, it'll just have to be worked around. I suspect I haven't seen the problem because I try to work in one parameter space or the other - either all Thiele-Small or all electro-mechanical.
E-M: Mmd, Mms, Cms, Rms, Sd, B, L, Re
T-S: Vas, Fs, Qms, Qes, Qts
Years ago I wrote a note to myself in my workbook:
"Suggested entry order for auto-calculators such as WinISD and LspCAD:
Qes, Qms, Fs, Vas, Re, Le, Xmax, Pe"
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Old 25th September 2012, 04:14 AM   #59
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Quote:
Originally Posted by Don Hills View Post
I deleted and typed in "47g" and also tried "0.47". They both evaluated the same.
Interesting, the manual lists the values that have alternate terms and Mms isn't one of them.

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Old 25th September 2012, 02:44 PM   #60
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Aaah. That's it - and it makes sense. My printout of the tutorial has been notated accordingly.

Thanks so much for your efforts - they are much appreciated!
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