These are really good horns mabat!
I'm not sure if anyone has done this already, but I'm experimenting with an alternative synergy horn concept.
Instead of making holes and bandpass chambers on the midrange drivers, I decided to mod a couple of 2" drivers I had laying around.
I removed the membrane and 3d printed one that matches the contour of the horn out of light weight pla that foams while printing.
Then I cout out a hole in an old horn and mounted the driver behind it. The new membrane weighs about 3g.
This is a very shabby first attempt. However with some tighter tolerances and membrane mass adjustment I think it might actually lead to something decent and justify some of the larger horn sizes here
I'm not sure if anyone has done this already, but I'm experimenting with an alternative synergy horn concept.
Instead of making holes and bandpass chambers on the midrange drivers, I decided to mod a couple of 2" drivers I had laying around.
I removed the membrane and 3d printed one that matches the contour of the horn out of light weight pla that foams while printing.
Then I cout out a hole in an old horn and mounted the driver behind it. The new membrane weighs about 3g.
This is a very shabby first attempt. However with some tighter tolerances and membrane mass adjustment I think it might actually lead to something decent and justify some of the larger horn sizes here
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I would try a coax this way.
As we already know, there's in general no problem even with a long tube in the throat of a WG (the EXT-1 adapter above is 135 mm deep), that can go through the whole magnetic system of a much larger midrange driver. The larger the diaphragm area, the smaller the excursion, the better, IMO.
25-EXT-1
As we already know, there's in general no problem even with a long tube in the throat of a WG (the EXT-1 adapter above is 135 mm deep), that can go through the whole magnetic system of a much larger midrange driver. The larger the diaphragm area, the smaller the excursion, the better, IMO.
25-EXT-1
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Basically what Genelec does. It wouldn't need to go very high, so maybe it would be manageable. To have 200 - 800 Hz this way would be sensational. Maybe even some simple foam suspensions would do the trick, otherwise they would need to be printed new - just some thin flexible rings. That's the kind of MEH I would be immensely interested in.
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OK, now I see a problem - the reflected sound that would go down to the compression driver diaphragm and back... This can't be a long distance. You'll probably get the first cancelation at a too low frequency this way. You would need to place the diaphragm as close to the throat as possible and/or go really low with the compression driver.
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The way I see it - the midrange will additionally load the CD at the lower end of things if they are in phase, which they can be at most frequencies of interest with the help of a fir filter
Besides, the MF's high frequency output would like to go where the impedance is low - outwards.
Or is my intuition wrong?
The compression driver has nothing to do with this. It's the sound radiated by the midrange diaphragm that gets reflected back at the end of the throat. But I gave up acoustic intuition a long time ago, maybe it's worth a try, even if it didn't work quite perfectly. An open-cell foam filling the throat would certainly help (to a degree).
In general, you would need to get below λ/4 with these things, but that's not always possible - and then you're in trouble no matter what.
In general, you would need to get below λ/4 with these things, but that's not always possible - and then you're in trouble no matter what.
Dead project, but I had some similar thoughts in the past.
https://www.diyaudio.com/community/threads/18-90-deg-os-wg-coaxial-design.261511/page-4#post-4116362
So you mean, the outer driver/diaphragm of the coaxial should be more like an annulus with relatively large ID, as opposed to looking like a regular woofer with a somewhat-large voice coil?
That would actually make the fabrication of a custom diaphragm a bit easier... that's kind of where the project stopped for me, I really did not want to get into forming & shaping a sheet metal part with such exacting precision. But the larger voice coil also makes things tricky too.
That would actually make the fabrication of a custom diaphragm a bit easier... that's kind of where the project stopped for me, I really did not want to get into forming & shaping a sheet metal part with such exacting precision. But the larger voice coil also makes things tricky too.
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That's what I meant. Details may vary, I would place the upper suspension (the "surround") between the new diaphragm and the waveguide. This would reduce the moving mass quite a bit. Also with the lower suspension, it could be a flexible ring placed at the joint, leaving no cavities. The existing spider could stay, I guess. The aim would be to keep the excursion at minimum, and the required diaphragm area would need to be found out.
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Would be practical for testing purposes but I don't think the performance with a 3D print (at least, with FDM or SLA) would be very good.
Also, depending on SPL requirements, one might find that the diaphragm does in fact need to be very big in order to stay below some arbitrary threshold of Xmax (i.e. 0.5 mm peak-to-peak) to avoid modulation/diffraction effects and/or excess strain on one or both "surrounds". Trying to remember off the top of my head, the ~18" diaphragm size was what was needed in order to hit ~105 (maybe 110) dB @ 1 m when crossing at 250 Hz or something like that, with Xmax < 0.5 mm.