Greeting all,
having acquired Heil as per may other post and being inspired by others, @Cask05, @pelanj, @xrk971, I dusted-off my meager Solidworks skills, and started working on a wave-guide. The current plan is to make it form a 5 mm foam board sandwiched between two 2 mm plywood. So even with the rather smallish dimensions 15.5 in x 11 in x 6 in (planned to be eventually extended), it will be relatively heavy.
I have been contemplating how to attach it to the Heil, without having to mutilate the Heil. I was contemplating a flange at the throat of the wave-guide and brackets between that and the existing holes through the top and bottom; another flange positioned at the bask of the Heil and screws tying the two flanges together, but they both seem rather inelegant. I am also not sure whether any non-permanent glue, e.g., silicon would adhere to the Heil plastic.
So, any creative ideas would be appreciated.
Kindest regards,
M
having acquired Heil as per may other post and being inspired by others, @Cask05, @pelanj, @xrk971, I dusted-off my meager Solidworks skills, and started working on a wave-guide. The current plan is to make it form a 5 mm foam board sandwiched between two 2 mm plywood. So even with the rather smallish dimensions 15.5 in x 11 in x 6 in (planned to be eventually extended), it will be relatively heavy.
I have been contemplating how to attach it to the Heil, without having to mutilate the Heil. I was contemplating a flange at the throat of the wave-guide and brackets between that and the existing holes through the top and bottom; another flange positioned at the bask of the Heil and screws tying the two flanges together, but they both seem rather inelegant. I am also not sure whether any non-permanent glue, e.g., silicon would adhere to the Heil plastic.
So, any creative ideas would be appreciated.
Kindest regards,
M
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My plan to mount the AMT to the next horn/MEH is very similar - I would build a small box around the AMT that is fixed to the flange and then use a rectangular frame with foam and bolts to press the AMT against the horn throat. The box will also have an option to mount a "dagger" style back chamber if I find it necessary.
Hi TNT
Hi pelanj,
thank you for your answer.
Kindest regards,
M
I do not understand your question.
Hi pelanj,
thank you for your answer.
Thank you for the suggestion. That is similar to my second option, as it would allow for the back chamber, if found necessary.
Kindest regards,
M
Hi Drummer2005.
I would have never guessed from the formulation, but the horizontal angle is 90 deg, which is set by the Heil's expansion in that direction, the vertical is 80 deg. The latter should not not restrict the vertical dispersion since, as I understand it, it is again set by the Heil to 30 deg.
I had chosen the vertical directivity because (i) I neded to start somewhere, (ii) I wanted to close the wave-guide for potential inclusion of mid-range drivers à la MEH, while not interfering with the Heil's dispersion - some people reported negative subjective impressions, and (iii) to potentially reuse the vertical portion for potential stacking.
All this may change once I build the first one and measure it.
Kindest regards,
M
I would have never guessed from the formulation, but the horizontal angle is 90 deg, which is set by the Heil's expansion in that direction, the vertical is 80 deg. The latter should not not restrict the vertical dispersion since, as I understand it, it is again set by the Heil to 30 deg.
I had chosen the vertical directivity because (i) I neded to start somewhere, (ii) I wanted to close the wave-guide for potential inclusion of mid-range drivers à la MEH, while not interfering with the Heil's dispersion - some people reported negative subjective impressions, and (iii) to potentially reuse the vertical portion for potential stacking.
All this may change once I build the first one and measure it.
Kindest regards,
M
One way to approach it would be to include a base plate for the whole contraption. You could build off that to make a shelf the Heil sits on/is bolted into. That way it's not hanging off the waveguide. Similarly, you could run all-thread rods up from the base and through the Heil (assuming those holes go all the way through - I'm not sure if they do).
However you approach it, I'd try to get a flat plane on the back of the waveguide that you can interface to. With enough epoxy, Liquid Nails, Bondo, whatever you like, this could be added to the waveguide without a precise fit on all its complicated angles.
I would not glue anything to the Heil. If you want to seal things, weather stripping can be applied to the waveguide. When I'm prototyping, I also use a lot of masking tape to hold and seal things. Not the most permanent solution, but that's the point. It's pretty much the fastest gap sealer/assembly method for things that don't need to support much weight. Early on, most of what I'm doing gets rapidly undone, and I don't want to invest a bunch of time or material until it's justified.
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If you have access to a 3D printer, I can send you the STL or F360 file for this AMT interface https://www.diyaudio.com/community/...eter-faitalpro-3fe22-mids.400527/post-7389250
Hi mattstat,
thank you for the reply.
Hi pelanj,
Kindest regards,
M
thank you for the reply.
This is a great idea, I think that I will do it in this manner. I knew there were people smarter than I.
Hi pelanj,
Thank you for your generous offer. But, to paraphrase Inigo Montoya: "I do not think that the picture shows what you think it shows." I will send you a p.m. to discuss.
Kindest regards,
M
I don't know who's smarter, but one of the benefits of these communities is that lots of people have built many different things, and there are all kinds of ideas floating around both online and in people's heads.
Hot glue - that's another one you could use to gap fill/bond on poorly fitting bits.
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Hi mattstat,
Kindest regards,
M
Well, I do. 😉
I am not worried about the gaps, I know how to deal with those, just the attachment so that pieces do not fall apart.
Kindest regards,
M
I've done a lot of experimentation with waveguides on dome tweeters and other drivers. I always found that it took a lot of experimentation, i..e. many prototypes, to get to something that worked well. Because of this I ended up making waveguides out of cut cardboard (usually the stuff that comes on the back of a pad of writing paper.
It is more rigid than you would guess at audio frequencies and you can tape and glue sides together. Once you have a design that works you can duplicate it in your favorite materials, but at least you can work quickly through a bunch of profiles. (I never got a waveguide to work in less than 6 to 10 iterations).
David
It is more rigid than you would guess at audio frequencies and you can tape and glue sides together. Once you have a design that works you can duplicate it in your favorite materials, but at least you can work quickly through a bunch of profiles. (I never got a waveguide to work in less than 6 to 10 iterations).
David
Hi David,
thank you for the suggestion.
I was initially thinking about using a matting paper, but I was afraid that (i) it would be too flimsy and (ii) it would not be opaque enough.
Saying that, it was not too time-consuming to build the above. I have a nice hobby scroll saw, thus I could keep close to the line so sanding was not doo difficult. However, I might use your idea for the vertical parts as I do not fancy bending plywood.
Kindest regards,
M
thank you for the suggestion.
I was initially thinking about using a matting paper, but I was afraid that (i) it would be too flimsy and (ii) it would not be opaque enough.
Saying that, it was not too time-consuming to build the above. I have a nice hobby scroll saw, thus I could keep close to the line so sanding was not doo difficult. However, I might use your idea for the vertical parts as I do not fancy bending plywood.
Kindest regards,
M
You'll find that a lot of materials are more suitable than you would guess, at least for, say, 500 Hz and up. I made a lot of tweeter flares out of manila folder material. I got good at calculating the sections to make a multisection conical flare. The samples were good enough to measure and were used in preliminary listening tests too.
Good luck.
Good luck.
Greetings all,
Sophisticated gluing fixture:
and the result:
Kindest regards,
M
Sophisticated gluing fixture:
and the result:
Kindest regards,
M
Hi drumdoctor,
the project was finished - in a third world sort of way, as you can ascertain from the sophisticated wave-guide to Heil attachment in the pictures below.
I performed some measurements, but I am reluctant to believe them, since the response is within 2 dB from about 580 Hz to 20 kHz.
Regardless, not being a golden ear, I am so pleased with the result that I am designing a permanent interface between the wave-guide and the Heil, and once I have one 3D printed and satisfy myself that it works as intended, I will build a second wave-guide.
After some discussion with @pelanj, I started to contemplate making the wave-guide larger and adding drivers a la MEH to extend the covered bandwidth. I am also contemplating better mouth termination; however, as best as I can tell, ATH by @mabat cannot model square source. Perhaps just a big radius or a Tractrix curve would work?
Kindest regards,
M
the project was finished - in a third world sort of way, as you can ascertain from the sophisticated wave-guide to Heil attachment in the pictures below.
I performed some measurements, but I am reluctant to believe them, since the response is within 2 dB from about 580 Hz to 20 kHz.
Regardless, not being a golden ear, I am so pleased with the result that I am designing a permanent interface between the wave-guide and the Heil, and once I have one 3D printed and satisfy myself that it works as intended, I will build a second wave-guide.
After some discussion with @pelanj, I started to contemplate making the wave-guide larger and adding drivers a la MEH to extend the covered bandwidth. I am also contemplating better mouth termination; however, as best as I can tell, ATH by @mabat cannot model square source. Perhaps just a big radius or a Tractrix curve would work?
Kindest regards,
M
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Thanks so mu for your reply! That’s great
Im thinking about something similar maybe with two Heils. So this single Heil is going all the way down to 580? If so, that’s really impressive.
I bought mdf round overs from White River for another project. They might make a nice termination for the waveguide. They’re offered in a couple different sizes and are designed to attach to an MDF panel.
Im thinking about something similar maybe with two Heils. So this single Heil is going all the way down to 580? If so, that’s really impressive.
I bought mdf round overs from White River for another project. They might make a nice termination for the waveguide. They’re offered in a couple different sizes and are designed to attach to an MDF panel.