Spreadsheet for Folded Horn Layouts... - Page 4 - diyAudio
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Old 13th August 2010, 03:51 AM   #31
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Quote:
Originally Posted by soho54 View Post
I will need the temp where you were at the time you took the measurement, and altitude as well to see what a difference it will make.
Temp=29C
Altitude=~75 ft above sea level
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Old 13th August 2010, 04:49 AM   #32
soho54 is offline soho54  United States
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OK, for 29c at 22.86m above sea level I get a speed of sound of 348.444m/s, with an air density of 1.165009649kg/m3.


Here is the default AkAbak sim on the left, and the adjusted constants on the RIGHT.
Click the image to open in full size.

Last edited by soho54; 13th August 2010 at 05:06 AM.
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Old 13th August 2010, 01:39 PM   #33
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Originally Posted by Brian Steele View Post
Vol (1) is calculated using S1, S4 and L, and it's not dependent on any of the measurements of the box, so it's somewhat misleading at this point.
My fault Brian! I knew about the Vol (1) calculations. I should have stated {Vol (2) = Vol (1)}.

Is the centerline version available for download?
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Old 13th August 2010, 03:40 PM   #34
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Originally Posted by BP1Fanatic View Post
My fault Brian! I knew about the Vol (1) calculations. I should have stated {Vol (2) = Vol (1)}.

Is the centerline version available for download?

Version 1.2.0 attached.

1. Plot options added for driver (top-mount and bottom-mount), centerline, advanced centerline, minimum length, maximum length.

2. Goal-seeking for effective length is now included (default is advanced center line, but the other options are also provided). This unfortunately complicates the operation of the spreadsheet a bit - I'm going to check to see if it can be simplified.

3. I've cleaned up the format of the spreadsheet a bit.
Attached Files
File Type: zip Stepped TH.zip (21.4 KB, 102 views)
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Old 13th August 2010, 04:07 PM   #35
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Forgive my manners - I forgot to thank "Soho54" for the "advanced-centerline" idea to determine the effective length of the horn. After reviewing each of the different methods yet again, that method seems to produce the closest match to the results that I obtained with POC #2.

I forgot to mention that I also fixed two minor bugs with the calculations for the panel dimensions. One bug made the driver's baffle slightly too long, and the other made the internal panel on the other side of the mouth slightly too long as well. These are corrected in v1.2.0
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Old 14th August 2010, 04:36 AM   #36
soho54 is offline soho54  United States
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Hey thank you, for taking the time to putting this spreadsheet together.

I'm glad you caught the two odd panel lengths. They were the reason I asked for you to verify my model was what you built.
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Old 14th August 2010, 05:03 AM   #37
soho54 is offline soho54  United States
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I also finished up the Hornresp model.

As this fold is a "digitized" fold of a single flare rate horn it has several straight sections that will give HR a minor hiccup. Mainly the middle impedance spike will hit a couple hertz higher, and the resonate frequency will be a little bit higher. There is also the case of the drivers mounting sections, but it's effects are minor in the scheme of things.

I also noticed once you get done it will be easy to get the data to put into HR or AkAbak. Very nice sheet.

I don't know why I had that voltage in there?
Click the image to open in full size.
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Old 14th August 2010, 02:01 PM   #38
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Originally Posted by soho54 View Post
I also finished up the Hornresp model.

As this fold is a "digitized" fold of a single flare rate horn it has several straight sections that will give HR a minor hiccup. Mainly the middle impedance spike will hit a couple hertz higher, and the resonate frequency will be a little bit higher. There is also the case of the drivers mounting sections, but it's effects are minor in the scheme of things.

I also noticed once you get done it will be easy to get the data to put into HR or AkAbak. Very nice sheet.

I don't know why I had that voltage in there?
Click the image to open in full size.
Eek - how did you end up with 198.72 cm^2 for S1? My target for S1 was 270 cm^2
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Old 14th August 2010, 02:12 PM   #39
Mark Kravchenko --- www.kravchenko-audio.com
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Quote:
Hey thank you, for taking the time to putting this spreadsheet together.
I am remise in adding my thanks as well. I can only vaguely understand how work went into this Brian. If you keep tweeking it it will be a very powerfull piece of code. THank you very much for your work!

I'm still playing with it.

Mark
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Old 14th August 2010, 05:23 PM   #40
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Originally Posted by soho54 View Post
Hey thank you, for taking the time to putting this spreadsheet together.

I'm glad you caught the two odd panel lengths. They were the reason I asked for you to verify my model was what you built.
I didn't think the panel length errors would cause to much issues. Panel F was about 1~2mm too long and Panel I was about 5mm too long. There are some approximations involved with Panel F's position, so it's best to lay out the rest of the horn, then use Panel F to join Panel G to Panel A.

I've attached v1.3.0 of the spreadsheet - this version allows the user to highlight specific panels in the graph. I've indicated in the plot which panels were incorrectly sized.
Attached Files
File Type: zip Stepped TH 1.3.0.zip (23.8 KB, 88 views)
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