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Yeah I think our coming to different positions on whether hard domes are easier or harder to work with, was due to the path we took at the beginning. You used off-the-shelf waveguides, which tend to be some form of quasi-OS, so your struggled with hard domes, but soft domes worked well. I started with wanting to 3D print, so I had to learn CAD. With little CAD skill, it was easier for me to model profiles based on a simple circle. Which simply by chance worked well with hard domes, but not soft. I think that itself might be a worthwhile lesson to anyone following along. And I will state with some certainty that hard domes do better with circle-based wall profiles, not just from my own measured results, but also the results of working with ABEC to try different contours, including an actual OS.
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Refined a couple of the previous designs and measured them today. Also added the first variant for the Peerless DA25TX. I'm surprised by the Peerless, it's a small dome which has worked well for me, but this has a big dip on axis. I would have expected it to measure very close to the SB26ADC given how similar the domes are. I may have to start working in ATH/ABEC for this one to figure out what works.
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I removed the screen on the Peerless, and the faceplate on the Scanspeak.Comment
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Here are some measurements of the Bliesma T25A, to see how it measures on the waveguides I made for the T25B. The domes are very different, the A version is much taller. Clearly there is an issue here, which is disappointing.
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Thanks for the reply the other day, missed that you had these posted. Thanks to everyone involved in these projects, massive help to us less knowledgeable/able diy'ers.
Anyone think they would do decent firing straight back in a car? So I'd be approximately 45° off axis from the drivers side and 30° of axis form the passenger side. Perhaps the null between 0-10° may be beneficial since they would be in the sails panel area firing straight back at the door/window frame.
Any plans to test the T25S-6? Have a pair I may be able/willing to loan out
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Originally posted by augerpro View Post
Have you tried any waveguides with planars/ribbons, and or AMT air motion transformers? Any thoughts as what type(s) of curvature(s) and throat angles might be appropriate?"Our Nation’s interests are best served by fostering a peaceful global system comprised
of interdependent networks of trade, finance, information, law, people and governance."
- from the October 2007 U.S. Naval capstone doctrine
A Cooperative Strategy for 21st Century Seapower
(a lofty notion since removed in the March 2015 revision)Comment
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I'd really like to get around working with AMTs. Just haven't had time. No idea what contour would work, but I think they might be able to be treated as plane wave sources, which makes design easier to model in something like ABEC. OS or conical would probably work well.Comment
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I've tried a few WGs with planar tweeters that provided adequate, but not outstanding results. I'm curious about others experience.Originally posted by JRT View Post
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Ignore my comment on the post, wasn't sure how this forum works.Originally posted by augerpro View PostHere are some measurements of the Bliesma T25A, to see how it measures on the waveguides I made for the T25B. The domes are very different, the A version is much taller. Clearly there is an issue here, which is disappointing.
Thanks for the reply the other day, missed that you had these posted. Thanks to everyone involved in these projects, massive help to us less knowledgeable/able diy'ers.
Anyone think they would do decent firing straight back in a car? So I'd be approximately 30° off axis from the drivers side and 45° of axis form the passenger side. Perhaps the null between 0-10° may be beneficial since they would be in the sails panel area firing straight back at the door/window frame.
Any plans to test the T25S-6? Have a pair I may be able/willing to loan outLast edited by The Oneness; 01-08-2022, 10:29 PM.Comment
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Here are two more variants of the T34B waveguides, and a new Scanspeak R2904/7000 waveguide. I'll be adding the T34B designs to my website in a few weeks.
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'm making a test cabinet to do some research on edges before I start final designs on a family of speakers. This gave me a chance tonight to try my routing template. Worked as expected, so I'll get them posted on the website soon. This will require changing all of the waveguides a bit, so if you are relying on using the routing template, I would hold off on downloading any waveguide files right now. You'll know when you can download them when the template files are available, and I always have a revision log at the top of every page where I note updates.
I tried using double-sided tape to hold the template in place, but it didn't stick well. I ended up using a finish nailer to attach. I thought about integrating screw holes into the design, but I like that the finish nail leaves a tiny mark that is easy to fill. Any other ideas for attaching them before I do a final template design?
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Do a search for blue tape and super glue method or blue tape and CA glue method.
Also, maybe try a different double sided tape. The most recent stuff i got from Menards was way too sticky and would actually pull up the mdf. I settled on a compromise and used the blue tape with the overly sticky double sided tape in between.Comment
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I'd rotate the SB woofer 90 degrees counter-clockwise
Craig
I drive way too fast to worry about cholesterol.Comment
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I like the blue tape on both pieces with CA glue in between. Small marks at the bottom of the template hole makes it easier to align the template. The router bushing rides higher than the marks or rides over any indentations.Comment
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I've finally added router templates for elliptical waveguides to my website! You'll need 5/16" OD and 1" OD template guide bushings to use them. There are holes that will accept #4 sheetmetal screws, or you can use a finish nailer, or double-sided tape to attach them. https://www.somasonus.net/waveguidesComment
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