3D printed waveguides

[augerpro]

Ok first results are SB26 5" version H. It doesn't get much better, so I'm calling the 5" done. Note whether a phase shield is included.







For fun I wanted to go with a more round mouth, so here is a 5" but with mouth aspect ratio of 1:.80







Not really anything to gain. But I will try a strictly circular mouth just to be sure I didn't go down the wrong path when went with elliptical mouths early on when the first circular mouths weren't very good.

Now the Bliesma T25B tweeter. I really like that the best response are without phase shield. I did a 5" with my normal 1:.618 aspect ratio mouth and another using 1:.80, two 6" of varying depth, and one 6.5".












A note about the high frequency spike @48khz: this is a combination of the mic calibration no longer being very accurate and the math of the FFT. None of these tweeters actually spike the high.

[augerpro]

Sometimes using just the 0 and 40 degree measurements are little clearer. Here are the Bliesma T25B results.

[augerpro]

[dlr]

How difficult is it to lay a design for a decent, basic, low volume printer? I want to build some dipole panels for various midranges and tweeters to experiment, but the tweeter is especially difficult because my goal is a very small surface, probably circular as in a section of a globe that is "sliced off", two back-to-back, not easy to do with mdf or hardwoods. Then there's the added difficulty of supporting them if they are separate pieces, my ultimate goal.

Second question, how do you lay out the 3d design to go into the printer? Common tools available or are more generic ones available?

dlr

p.s. May be answered earlier in the thread, but it's 20 pages and four years long, so I haven't read through it all.

[TN Allen]

Can you provide a sketch or photo of an existing design?

[augerpro]

How difficult is it to lay a design for a decent, basic, low volume printer? I want to build some dipole panels for various midranges and tweeters to experiment, but the tweeter is especially difficult because my goal is a very small surface, probably circular as in a section of a globe that is "sliced off", two back-to-back, not easy to do with mdf or hardwoods. Then there's the added difficulty of supporting them if they are separate pieces, my ultimate goal.

Second question, how do you lay out the 3d design to go into the printer? Common tools available or are more generic ones available?

dlr

p.s. May be answered earlier in the thread, but it's 20 pages and four years long, so I haven't read through it all.

Dave, I'm not sure what you mean exactly by "lay a design", but what you are proposing seems absolutely doable. Kind of where 3D printing excels really, so long as your CAD skills are up to the task. One complication is you must remember that it prints upward in layers with melted plastic that cools quickly. So "bridging" where it has to lay a layer out in space - perhaps because you have an overhang of some sort - can be tricky. The slicer software can generate support for this, but still something to be considered. Sort of like designing a mold for injection molding. The mold must be split and the part pulled out, so this limits the sort of shapes you can make. Maybe am illustration of what you are doing would help.

Work flow is just Fusion 360 for design, Simplify3D to slice, Ender 3 Pro to print. Simplify3D is spendy, Cura is free and also very good. Fusion 360 has a free hobbyist license, so software can absolutely be free for the whole process.

[augerpro]

Can you provide a sketch or photo of an existing design?

More than the pic in post #588?

[dlr]

Can you provide a sketch or photo of an existing design?

No, it will be of my own design, initially typical of some dipole baffles, circular baffles mounted one above the other in some fashion or an extended single piece with a narrow support section between drivers. Ideally the baffle will be two identical pieces with a flat back, a driver mounted in each, then attached back-to-back somehow. The requirement of drivers mounted back-to-back is the difficult part, since the drivers can't just be inserted from behind as done in a standard baffle. I also want minimal depth for best dipole response. The midrange and tweeter will both be back-to-back mounting.

The tweeter is the more difficult since as it isn't obvious to me how to cut a small baffle for two tweeters mounted back-to-back with a flush mount for the tweeters. Small is the goal, to have true dipole operation as high as possible. It will be a four way, so the tweeter crossover can be fairly high. I would like to test a fair number of very small tweeters as well, so a printer would be ideal. Depth (baffle thickness) will have to vary for each one with some experimentation on the baffle edge shape.

dlr

[dlr]

Dave, I'm not sure what you mean exactly by "lay a design", but what you are proposing seems absolutely doable. Kind of where 3D printing excels really, so long as your CAD skills are up to the task. One complication is you must remember that it prints upward in layers with melted plastic that cools quickly. So "bridging" where it has to lay a layer out in space - perhaps because you have an overhang of some sort - can be tricky. The slicer software can generate support for this, but still something to be considered. Sort of like designing a mold for injection molding. The mold must be split and the part pulled out, so this limits the sort of shapes you can make. Maybe am illustration of what you are doing would help.

CAD skills are minimal. For now. By layout, I mean creating the input for the printer. I still tend to use old-school wording at times, from back when I had to "lay out" a control panel in a factory by hand drawing it. Tedious to say the least.

Work flow is just Fusion 360 for design, Simplify3D to slice, Ender 3 Pro to print. Simplify3D is spendy, Cura is free and also very good. Fusion 360 has a free hobbyist license, so software can absolutely be free for the whole process.

Thanks for the references. I'll have to check them out. Of course the next step will be choosing a printer. Very low volume as I don't have plans to do a lot with it.

dlr

[TN Allen]

"No, it will be of my own design, initially typical of some dipole baffles, circular baffles mounted one above the other in some fashion or an extended single piece..."

Sounds interesting, if you're not in a hurry, I may be able to help you make start with design and printing and/or milling. That may help you explore possibilities before putting much into learning software and buying a printer.

I think I understand your idea, a sketch will help though. The above would be free of charge in the interest of research.

[augerpro]

Thanks for the references. I'll have to check them out. Of course the next step will be choosing a printer. Very low volume as I don't have plans to do a lot with it.

dlr

I highly recommend the Ender 3 Pro. Perfect entry into 3D printing for the price.

[ani_101]

Hey Brandon

The wave guides are looking very impressive. Is there any notable difference between circular, 1:8 and 1.66 mouth on the horizontal axis?

Any rule of thumb that can be generalized for most tweeters? for eg, mouth / throat diameters, curve from moth to throat and the angle at the throat? Trouble areas to look out for that may rule out suitablility of any tweeters?

I also took a look at the ender 3 Pro, looks like it's available for 199 at Micro center - that is a really good price - thinking of getting one. Any basic mods you recommend?

[dlr]

"No, it will be of my own design, initially typical of some dipole baffles, circular baffles mounted one above the other in some fashion or an extended single piece..."

Sounds interesting, if you're not in a hurry, I may be able to help you make start with design and printing and/or milling. That may help you explore possibilities before putting much into learning software and buying a printer.

I think I understand your idea, a sketch will help though. The above would be free of charge in the interest of research.

I posted a reply, it just...disappeared. Anyway, my thanks for the offer, I'll continue with the PM. As it had said, I'm inclined to get the Ender 3 Pro, it's on sale, but I'll followup at some time later.

dlr

[augerpro]

Hey Brandon

The wave guides are looking very impressive. Is there any notable difference between circular, 1:8 and 1.66 mouth on the horizontal axis?

Any rule of thumb that can be generalized for most tweeters? for eg, mouth / throat diameters, curve from moth to throat and the angle at the throat? Trouble areas to look out for that may rule out suitablility of any tweeters?

I also took a look at the ender 3 Pro, looks like it's available for 199 at Micro center - that is a really good price - thinking of getting one. Any basic mods you recommend?

Horizontally, I use the same profile for a given width. So they are the same in that direction. Hard and fast rules have been tough to come by. But smaller throats are good. Tighter angles at the throat seem better on average. Bigger and deeper works best, with the smaller waveguides big throats or wide surrounds on the tweeter are too tough to deal with. I've made the mistake of tweaking a bunch of stuff on a printer before you have it running, my advice would be just to build as is. As issues crop up, solve them one at a time.

[ani_101]

Thanks Brandon, now that decent printers are accessible, making tweaks should be relatively easier.