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The making of: The Two Towers (a 25 driver Full Range line array)
The making of: The Two Towers (a 25 driver Full Range line array)
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Old 21st February 2021, 10:06 AM   #6671
fluid is offline fluid  Australia
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This is quite a simple one to make changes on and it doesn't take a huge amount of time to simulate, the last one took 58 minutes due to being a denser mesh that the first ones.

This would be a good starting introduction as you already understand the model so explaining what is happening in the script would be easier. You decide if or when you want to dip your toes in the water
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Old 21st February 2021, 10:32 AM   #6672
wesayso is offline wesayso  Netherlands
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New model is going in your direction, email send, a slight tweak to add the front gasket dimensions.
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Old 21st February 2021, 04:34 PM   #6673
wesayso is offline wesayso  Netherlands
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Finally some good weather over here, so I could pick up some work in the garage again. The bad thing is that the extensive break had me going nuts with extra simulations, so I made up a few extra filters, as mentioned earlier in this thread. A few bypass filters that go in parallel with only one driver in a string of 5. So instead of finally closing up the first array I was actually making more filters...

The 4 extra filters (2 per array), below the first set of filters for the second array:

The making of: The Two Towers (a 25 driver Full Range line array)-bypass-filters-jpg

and their impedance measurements against an 8 ohm resistor:

The making of: The Two Towers (a 25 driver Full Range line array)-bypass-boards-jpg
(that's all 4 of them + the resistor, good enough quality control I'd say)
Attached Images
File Type: jpg bypass filters.jpg (282.9 KB, 154 views)
File Type: jpg bypass-boards.jpg (59.4 KB, 162 views)
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Last edited by wesayso; 21st February 2021 at 04:50 PM.
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Old 21st February 2021, 09:47 PM   #6674
wesayso is offline wesayso  Netherlands
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Question for fluid,

I read a lot about the meshing of objects and ABEC can read stl.
Depending on a couple of variables I can let Inventor decide where the triangles should go. I won't have total control, but it seems smart enough not to divide the larger area's into smal triangles.

Here's a more standard way to mesh as stl:
The making of: The Two Towers (a 25 driver Full Range line array)-stl1-jpg
mesh size set to ~5mm edge length, the deviation (another variable) determines the number of slices to use for more complex shapes.
So even if I set the edge length to something like 50mm:

The making of: The Two Towers (a 25 driver Full Range line array)-stl2-jpg

Due to the surface deviation allowed, it will divide large flat faces into big pieces, and only use smaller ones to be true to the original shape.
This deviation setting is limited though. it varies from 0.003595 to 0.3595.
There are two other variables left that also determine the end outcome, but I'd have to guess what it is they do.

Would this help? I see a lot less triangles in the second example, except where it counts to stay true to the original shape.

Edit: just played with the "normal deviation variable, this one allows to create even simpler shapes decreasing the triangle count further.
The making of: The Two Towers (a 25 driver Full Range line array)-stl3-jpg

All of them are sliders, though with limited choices.
Attached Images
File Type: jpg stl1.jpg (108.2 KB, 153 views)
File Type: jpg stl2.jpg (56.2 KB, 152 views)
File Type: jpg stl3.jpg (50.9 KB, 144 views)
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Last edited by wesayso; 21st February 2021 at 09:56 PM.
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Old 21st February 2021, 10:39 PM   #6675
wesayso is offline wesayso  Netherlands
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One more quick note...
If it's needed to have a seam exactly on a quadrant, you can get it.
There's a tool available to cut the solid model (it's faces) with a plane:

The making of: The Two Towers (a 25 driver Full Range line array)-stl4-jpg

Which would make the STL file have those seams as well:

The making of: The Two Towers (a 25 driver Full Range line array)-stl5-jpg
Attached Images
File Type: jpg stl4.jpg (28.4 KB, 138 views)
File Type: jpg stl5.jpg (59.5 KB, 140 views)
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Old 21st February 2021, 10:45 PM   #6676
fluid is offline fluid  Australia
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The first one will work the best but there is way too many triangles for the surround to deal with the curvature, for a one off you could let that run and it would give good results but it would take a while.

The third one is about right for the surround but the main panels have quite large triangles.

The edge length needs to be kept below 20mm and ideally 10mm for the front baffle in order to have valid results up to 12 to 15K. Beyond the front it matters much less. Sometimes you can mesh it in two different densities and save them separately and only call specific faces at high or low resolution. That only works for square corners or rectangular surfaces of which you have none where it might work.
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Old 21st February 2021, 11:00 PM   #6677
fluid is offline fluid  Australia
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Quote:
Originally Posted by wesayso View Post
There's a tool available to cut the solid model (it's faces) with a plane:
That image is exactly what I do by splitting the bodies with the y and x planes then hiding the quadrants I don't need.

You can also model the driver separately, export the mesh from ABEC with all symmetry and use that as a template to cut the baffle or chamfer so the vertices that will be used in ABEC match those on the solid model.

In fusion I create a surface patch to cover the surround or chamfer and then use that to extrude a cut or split a body apart. By converting mesh to Brep solid tools can be used on the mesh points.

Then when meshed those vertices are kept. Inventor could probably do the same.
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Old 21st February 2021, 11:05 PM   #6678
wesayso is offline wesayso  Netherlands
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Just looking for easy ways to get the information where one would want it. I can split anywhere without too much trouble by cutting the object with a plane.
That way the two objects should be suitable to be stitched together without error.

The 3rd option, with 10mm edge size:
The making of: The Two Towers (a 25 driver Full Range line array)-stl6-jpg
Attached Images
File Type: jpg stl6.jpg (111.1 KB, 146 views)
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Old 21st February 2021, 11:14 PM   #6679
wesayso is offline wesayso  Netherlands
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Quote:
Originally Posted by fluid View Post
That image is exactly what I do by splitting the bodies with the y and x planes then hiding the quadrants I don't need.

You can also model the driver separately, export the mesh from ABEC with all symmetry and use that as a template to cut the baffle or chamfer so the vertices that will be used in ABEC match those on the solid model.

In fusion I create a surface patch to cover the surround or chamfer and then use that to extrude a cut or split a body apart. By converting mesh to Brep solid tools can be used on the mesh points.

Then when meshed those vertices are kept. Inventor could probably do the same.
The new one will , I'm still using an ancient version that lacks a lot of surface tools (but had some other important features for me, that were crippled in later versions when I was working on my Apfelbeck project).
I have/use the new one at work and it features basically everything that Fusion has.

Just trying think of ways to keep prep to a minimum .
I am used to model in solids, so having to think in surfaces is somewhat new to me . Fusion (to me) is like being in your favorite store, but someone rearranged all the products!
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Old 21st February 2021, 11:24 PM   #6680
fluid is offline fluid  Australia
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One thing that gmesh does that I suspect an stl file will not do is tag the contiguous surfaces from the step file separately. So to define the driver you might select tags 1, 2 and 3, without tags you might have to have the sections as separate STL files.

That mesh look a lot better, high element count but not ridiculous for no reason.

I feel the same about Inventor, why did they hide the sauce in the pet food aisle

Rhino seems to be the best for surfacing, but that feels like being blindfolded in a new supermarket
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