Spreadsheet for Folded Horn Layouts... - Page 5 - diyAudio
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Old 14th August 2010, 05:25 PM   #41
Khron is offline Khron  Romania
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Greetings,

First of all, a big "thank you" to you, Brian Steele, for putting in the effort and man-hours into this spreadsheet

A few... requests or tips, however you wanna call'em, though:

- Maybe put some short descriptions of the dimensions to their right (the current names are a bit... interpretable. I mean, to me, it sounds like "mounting width" would be the driver mounting hole diameter, and the "frame width" would be the outside diameter of the frame. On the sketch, i can only get a speaker-looking thing if the "mounting width" is about twice the numerical size of the "frame width")

- Maybe include an "operating manual" on a second sheet within the .xls, for greater ease-of-access
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Old 14th August 2010, 05:44 PM   #42
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I mean, to me, it sounds like "mounting width" would be the driver mounting hole diameter, and the "frame width" would be the outside diameter of the frame.
That's correct.


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On the sketch, i can only get a speaker-looking thing if the "mounting width" is about twice the numerical size of the "frame width")
Yup, a bug. Looks like I was using frame radius instead of frame diameter in my plot calculations for the driver. I've fixed this in the attached spreadsheet.
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File Type: zip Stepped TH 1.3.1.zip (23.2 KB, 63 views)
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Old 14th August 2010, 05:58 PM   #43
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Originally Posted by Brian Steele View Post
That's correct.




Yup, a bug. Looks like I was using frame radius instead of frame diameter in my plot calculations for the driver. I've fixed this in the attached spreadsheet.
Grrr - forgot to turn back on some of the plots...
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File Type: zip Stepped TH 1.3.1.zip (23.6 KB, 75 views)
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Old 15th August 2010, 02:04 AM   #44
Khron is offline Khron  Romania
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Hmmm... I think some numbers are still slightly fudged in the driver sizes section...

Using the dimensions from this driver, i'm getting some "unnatural" driver shapes in the sketch
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Old 15th August 2010, 03:30 AM   #45
soho54 is offline soho54  United States
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Originally Posted by Brian Steele View Post
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.
The problem was two fold. The over sized panels which I didn't notice until I tried to get the last one (the baffle board) to line up correctly. When it didn't I just went off of the graph you posted on your web page.

Click the image to open in full size.

In it there is only ~4.8cm at the throat.

The graphs in your actually spread sheets are a lot better, so this shouldn't be a normal problem.

The possible panel length errors are an easy fix. You could make it a non-issue by posting the vertical and horizontal distances to define the first corner in space. As you are already checking those lines it shouldn't be a big deal to add in a box to list them. The extra length on the exit is not that big a deal.

Last edited by soho54; 15th August 2010 at 03:35 AM.
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Old 15th August 2010, 05:33 AM   #46
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Originally Posted by Khron View Post
Hmmm... I think some numbers are still slightly fudged in the driver sizes section...

Using the dimensions from this driver, i'm getting some "unnatural" driver shapes in the sketch
Yeah, it looks like I fixed the wrong dimension. Ok, fixed the right one this time. See attached (v 1.3.2)
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File Type: zip Stepped TH 1.3.2.zip (23.6 KB, 90 views)
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Old 15th August 2010, 06:08 AM   #47
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Originally Posted by soho54 View Post
The problem was two fold. The over sized panels which I didn't notice until I tried to get the last one (the baffle board) to line up correctly. When it didn't I just went off of the graph you posted on your web page.

Click the image to open in full size.

In it there is only ~4.8cm at the throat.
Yeah, something's not quite right with that graph. I've corrected it, thanks. The dimension at the throat should be 6.5 cm, not 4.8 cm. It looks like that version of the spreadsheet shifted the internal panels 1.7 cm (or one panel thickness) too high in the graph. The TH as built measures 6.5 cm at that point. The attached image is a closer match to what was actually built.

I made a few other errors with that build though that I'm not happy about, so I'm going to redo it next week. POC #2 part deux
Attached Images
File Type: gif Dayton PA310-8 TH (22).gif (38.8 KB, 428 views)
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Old 15th August 2010, 11:10 AM   #48
Mark Kravchenko --- www.kravchenko-audio.com
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Hi Brian

I've been messing around with the latest and greatest. It seems it will fold a bowtie type unhorn. I think it is doing what it should. I still have to work out the driver dimensions to make it look like a driver! But have you ever come a long way in user friendliness. Much more intuitive.

I'll throw in a couple more types of tapped horns into the mix and post some screen shots to see what you think.



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Old 15th August 2010, 04:36 PM   #49
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Originally Posted by mwmkravchenko View Post
Hi Brian

I've been messing around with the latest and greatest. It seems it will fold a bowtie type unhorn. I think it is doing what it should. I still have to work out the driver dimensions to make it look like a driver! But have you ever come a long way in user friendliness. Much more intuitive.

I'll throw in a couple more types of tapped horns into the mix and post some screen shots to see what you think.
That's curious, because it was designed with only one particular folding in mind, the idea being that I'd add additional worksheets to the workbook to cover other types of foldings (I might take a try at JBell's folding next, once I sort out the bugs with this one).

I ran into another bug with the optimization routine last night. Seems it only likes boxes with square cross-sections. Going to have a look at that later today.

Unfortunately vacation ends from tomorrow and they're calling me from work already, so I may not have a lot more time to devote to this project.

I've attached an example of what the spreadsheet looks like with the parameters for my POC #2 (with the correct dimensions for panels E and I). "L3" shows the predicted length of the horn, which is a very good match for my measurements. Some fudging aroudn with d and h suggests that I'll have to increase them to just over 60 cm to get the effective path length to the target of 245 cm. I might try that for my next POC
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File Type: gif Dayton PA310-8 TH (23).gif (40.6 KB, 426 views)
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Old 15th August 2010, 06:32 PM   #50
Mark Kravchenko --- www.kravchenko-audio.com
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Hi Brian

I'll say it like I think it.

Anything that is as usefull and as well intentioned and thought out as this spread sheet is worth waiting for. If you want to push it along so that horns can be folded all the more power to you. I for one really appreciate it. And I will wait however long is required to see what you consider a finished product. Folding a horn into the most compact shape is one of the greatest chaalenges left to the designer. I'd happily pay you for a spreadsheet that helped that process along.


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