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Old 7th January 2013, 07:29 AM   #1
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I know this is going to sound crazy but… I find the best way to learn about something I know absolutely nothing about, is to write a program about it.
To get my head around how the SPL rolls off based on baffle width, I have decided to write an app that allows me to simulate virtually any baffle shape (flat only at this time).

I know I am probably reinventing the wheel, and there is probably an app already out there that does exactly what I want to do, as I generally find out something exists right after I invent it.

Anyway who knows even if it has been done before I might come up with some new features that no one has tried before. So here goes…
The plan is to design any baffle I want and place the speaker anywhere I want and be able to calculate the frequency it begins to roll off.

Here is a quick mock-up of what the app might look like. Things like adjustable baffle size, edge points etc. are going to be features, so designing a baffle a 100m long should be doable.
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Old 7th January 2013, 11:19 AM   #2
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Still putting together some GUI ideas, but for a start I am looking to start with something like this.

The intial baffle points will be defined using two text boxes,but at a later date I will look at possibly sliders or mouse click to position the baffle point.

This is just a framework with little code behind it.

I would like to do an animated radar circle expanding from the driver until it touches the baffle boarder to show the contact point, and give some idea where it is going to touch, but that is probably way down the track.
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File Type: jpg New App 2.jpg (129.0 KB, 224 views)

Last edited by Silent Screamer; 7th January 2013 at 11:23 AM.
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Old 7th January 2013, 11:58 AM   #3
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Quote:
Originally Posted by Silent Screamer View Post
Still putting together some GUI ideas, but for a start I am looking to start with something like this.

The intial baffle points will be defined using two text boxes,but at a later date I will look at possibly sliders or mouse click to position the baffle point.

This is just a framework with little code behind it.

I would like to do an animated radar circle expanding from the driver until it touches the baffle boarder to show the contact point, and give some idea where it is going to touch, but that is probably way down the track.
Wish I had your programming talent! Good luck with your project. I believe EDGE is similar in concept, not sure if there's a radar plot though...
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Old 7th January 2013, 09:40 PM   #4
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Yes I have played around with Edge before, and it does seem to do a similar kind of thing by virtue of it allows you to place the speakers anywhere on the baffle, but it produces a graph output, where as I am trying to determine baffle size / shape and work out what Hz it rolls off.

I really don’t fully understand the concept of this effect, and I am sure by the time I write the app it will have brought in enough research that the concept sticks in my head whereas just reading a passage about it may not have the same long term effect.

Also I haven’t written anything for a while and I am getting rusty, so I need to get some coding in to brush up. Not sure how I am going to do the radar part just yet but the Graph object in VB gives me enough flexibility to draw up the baffle shape and allow it to be changed dynamically.

I will probably have to overlay the radar part as a separate paint object.

Edit:
Any suggestion / ideas for inclusion are welcome.

Last edited by Silent Screamer; 7th January 2013 at 10:01 PM.
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Old 7th January 2013, 10:47 PM   #5
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Another one that I am aware of is Quarter Wave by Martin King, see Baffle Step Sizing for an overview. Anyway, I think you should start a new thread in the speaker forum (may be the full-range one)? There are some real experts that hang out there. Good luck with your project.
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Old 7th January 2013, 11:07 PM   #6
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Thanks for that… with a quick look the formula for calculating F3 seems to be consistent with the one I found on the web. Until the other day I didn't even know what F3 was for.

Not sure how far I want to venture down the path of providing information about building correction circuits. At the moment I want to create an app that is more about being an aid to determine the best baffle shape to provide roll off information. Down the track I might want to get involved in the correction side of things.

Have decided this morning that I will use the vertical and horizontal slides in conjunction with the text boxes, as a means to make more detailed changes to the numbers. If I have it update the graph in real time, the text boxes will make the big movements the sliders will make the fine adjustments.
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Old 11th January 2013, 02:31 AM   #7
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Quick update... Have now coded all the controls on the left of screen dynamically (as apposed to statically popping them on the form).

I prefer to to this so when I resize the screen it is easier to maipulate the size of the controls and move them around.

I have made it so when I change either of the baffle points or driver count it will update the drop down box with the right amount of items.

If the baffle points radio button is checked. the first and last drop down box entries will result in the X & Y coordinate textboxes and slide control being disabled, as the first and last points must be at 0,0 to close off the baffle shape.

I have added a slide control to allow the size of the baffle to be altered, but there is not code behind it other than the code to draw it on the screen.

Here's a progress picture...
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File Type: jpg New App 3.jpg (121.4 KB, 176 views)

Last edited by Silent Screamer; 11th January 2013 at 02:34 AM.
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Old 11th January 2013, 12:57 PM   #8
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Too bad that a flat panel baffle model from say Sketch-up couldn't be loaded into one of these programs. Complex baffle shapes are a PITA to model in Edge .. as it works now.
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Old 11th January 2013, 11:42 PM   #9
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The plan is to eventually try and crudely model in 3D down the track, so I can evaluate things like H and U baffles, but I want to start in 2D to begin with just to get the basic concept down first.
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Old 11th January 2013, 11:57 PM   #10
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A large part of the graphical side is already completed (easy code)

The tough bit now begins... while I can draw the shape to screen, the values I will be using to measure the distance from the driver location to the nearest boundary will be quite diffacult.

To draw a line I only need to know 2 * X,Y points, but to measure from another point to any point along that line is going to be quite tricky.

I have decided to make the scaling of the baffle non infinate. at 1:1 the baffle will be 1 meter tall by .5 meter wide at 100:1 the biggest baffle possible will be 100 meters tall by 50 meters wide making it big enough to cover even fairly crazy baffle sizes.
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