BTW, I also assembled the new EXAR 400 and failed badly this time. I first glued together the petals to make the two halves of the horn, and even though everything seemed fine during the assembly, I found out at the end that they don't fit at all to each other - they were just twisted too much.
So, petal by petal, as shown here, is really the best procedure, as it doesn't allow the inaccuracies to add up. It's not a big problem to handle all the small imperfections separately with a suitable glue. I will update the kit so it includes the central jig for this. It simplifies the whole process a great deal.
So, petal by petal, as shown here, is really the best procedure, as it doesn't allow the inaccuracies to add up. It's not a big problem to handle all the small imperfections separately with a suitable glue. I will update the kit so it includes the central jig for this. It simplifies the whole process a great deal.
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I can make a purely round version as well, that's the least problem. The real problem is that seldom the printed parts will be so accurate that they form a perfectly round horn without the seams apparent. That was the idea behind the segmented shape in the first place - make the seams intentionally sharp so the dimensional imperfections don't show up so obviously. I can make a round version, but I had to warn you. It depends on what you expect.
BTW, the round version is already available. Not an STL kit yet, "just" the drawing (DXF file) and a printable template : https://cults3d.com/en/3d-model/various/ath-550ex
First quick measurements of EXAR 550. The angles can be roughly 0/10/20/30 but not exactly.
HF1440 and ROSSO-65CDN-T
Maybe for the HF1440 it could be shorter. Hmm, still to be surprised.
Both should do 500 Hz crossover with ease. I don't have a DSP at hand now but both will be very clean after EQ to flat between 500-10k.
HF1440 and ROSSO-65CDN-T
Maybe for the HF1440 it could be shorter. Hmm, still to be surprised.
Both should do 500 Hz crossover with ease. I don't have a DSP at hand now but both will be very clean after EQ to flat between 500-10k.
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I will measure the electrical impedances, free air and with the horn, if there's some kind of hint. This must be possible to design in advance, it's just that I'm still hesitant to dive deeper. For me, this means still to learn so much of the theory...
HF1440 has quite an atypical main resonance for a compression driver (not a lot damped), that's well known.
HF1440 has quite an atypical main resonance for a compression driver (not a lot damped), that's well known.
Here are the HF1440 and ND3T measured in a non-extended waveguide, only a bit smaller: https://www.diyaudio.com/community/...-design-the-easy-way-ath4.338806/post-7427264
In the extended horn, the resonance of HF1440 drops from 900 Hz to 500 Hz. This makes me think that a shorter extension would only move the resonance up, but the shape of the response would not change much.
In the extended horn, the resonance of HF1440 drops from 900 Hz to 500 Hz. This makes me think that a shorter extension would only move the resonance up, but the shape of the response would not change much.
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No, I still haven't found anything suspicious (see the raw ND3T below). But in my workroom I have only about 4 ms reflection-free time, so that's still quite limited. I was just impatient to see the overall frequency response. Going to measure also some of the smaller waveguides today.
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