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27th September 2012, 08:03 PM  #21 
diyAudio Member
Join Date: Mar 2008

Thanks for your comments Pete. Yes I did use VB.net to write the app.
I calculate the acoustic impedance of each element of the pipe and then add them all together in series. If you want to know in more detail I can, but maybe this thread isn't the best place. Thanks for the suggestion about enclosure volume. I will also update the t/sninput as per your comment. Cheers, Pete 
27th September 2012, 08:11 PM  #22 
diyAudio Member
Join Date: Jun 2008
Location: N.E. Ohio

Hi Pete,
Please don't abandon the parameter set you have now, but please expand with the ability to cross calculate. I too have some interest in the programming if it is open to discussion somewhere.
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Regards, Dan 
27th September 2012, 09:32 PM  #23 
diyAudio Member

I just downloaded the latest version and I can not enter Qts, Vas, etc. They are grayed out. What went wrong?

28th September 2012, 12:56 AM  #24  
diyAudio Member

Quote:
Pete you might also put a comment on the SPL graphs for the power input assumed, and really isn't it constant voltage so not really power? Giving power that is really constant voltage means we need to know the assumed load resistance or do you always use an 8 ohm reference? You might just give both, something like 100W  28.3Vrms. Once again Pete, thank you so much for this excellent tool! Last edited by PB2; 28th September 2012 at 01:22 AM. 

28th September 2012, 01:16 AM  #25  
diyAudio Member

Quote:
Here are the steps for the case with no driver offset (driver is at the start of the line) in case anyone is interested; Pete please let me know if you agree: 1. Calculate the radiation impedance of the port 2. Load the last section with the above impedance and calculate the input impedance. 3. Load the next closer section with that input impedance as the termination impedance. 4. Continue until you get to the line input impedance loading the driver. 5. Compute the volume velocity vs. frequency for the driver loaded by the first section input impedance. 6. You now have the volume velocity of the speaker cone. 7. Compute the first section volume velocity transfer function from input to output as loaded by the next section. 8. Repeat and compute all section transfer functions as loaded by the next section and finally the port. 7. Take the negative (back side of cone) of the cone volume velocity and use it as the driving source for the first section of line to compute the first section output volume velocity. 8. Repeat using each sections volume velocity transfer function until you get to the port output. 9. Plot cone and port output and vector sum them to get the total system output converting volume velocity to SPL at the assumed distance. 

28th September 2012, 01:29 AM  #26 
diyAudio Member
Join Date: Feb 2008
Location: Jackson,michigan

This a great program !!
I have tried to use the other ones for TL's but I just haven't been persistent in understanding how to use them. This one helps me to better understand changes that effect the results as I am just a Noob when it comes to TL's. Thank you!!! jer 
28th September 2012, 03:16 AM  #27 
diyAudio Member

Yes, the learning curve is about 10 minutes, probably less if you know TLs.
Amazingly well thought out! 
28th September 2012, 03:53 AM  #28  
diyAudio Member
Join Date: Jun 2008
Location: N.E. Ohio

Quote:
I do believe Pete has used the "conventional" data needed for the mathematical model. One must consider what's going on behind the curtain...
__________________
Regards, Dan 

28th September 2012, 03:58 AM  #29  
diyAudio Member
Join Date: Jun 2008
Location: N.E. Ohio

Quote:
__________________
Regards, Dan 

28th September 2012, 06:02 AM  #30  
diyAudio Member
Join Date: Mar 2008

Quote:
In the Amplifier window, you set the input power (in watts). It then uses the Re of the driver to calculate the input voltage sqrt(Re x Power). 

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