A Bookshelf Multi-Way Point-Source Horn

Founder of XSA-Labs
Joined 2012
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Being a sucker for punishment, I decided to stay up late and see if I could actually model a fibonacci spiral back chamber.... turns out you can! (+/-10%)
I will buy anybody a very large beer at the pub if they can work out how to 3D print this. ;)

Ps. Notice the pockets in the adaptor, plan would be to stuff with absorption.
Pps. Change .txt to .f3d


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Nice work! I think you can add 10% support matrix and infill to the void and let that act as the “stuffing”. It will serve as the support the structure and as the damping material. To do it just add a very thin solid wall that you can perforate later and peel off.
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Founder of XSA-Labs
Joined 2012
Paid Member
A 5 sided pyramidal back chamber filled with fiberglass (aka “Dagger”) rear chamber works very well. This is more compact and cooler technology though.

Benefits of absorbing the rear wave is less muddy sound for more clarity because the back wave doesn’t interfere with the front wave by bouncing off chamber and coming back out the front. It sounds like an open baffle speaker but it’s not.
 
Nice work! I think you can add 10% support matrix and infill to the void and let that act as the “stuffing”. It will serve as the support the structure and as the damping material. To do it just add a very thin solid wall that you can perforate later and peel off.
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I think I get it, although I just had another idea to flip the spiral so the rear of the drivers cone fires down the axis of the spiral... More soon
 
If you ever think about printing your own horns, the long running ATH thread is a must visit!
There's even some Synergy/Unity variants made with that crazy cool ATH tool. Just take a look here and here to see some very cool implementations.

These horns (generated with ATH) are quite worth looking in to, making a Unity/Synergy out of them would/could be the next step.
Preferably with woofers to have a very good horizontal plus vertical pattern control.
 
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Thanks lads, I was keeping up with ATH for the first 50 odd pages and lost track about 6 months back. It is on the books for the next horn, after I learn a bit more modelling/printing/horn skills.
Until then, I did an approximate (+/- 1degree)(+/- 1mm) model of the H280 from the outside, now I can model the woofer mounts for 3d printing.
Yes, I did have to fudge the loft from the 35mm throat to the horn walls but its not critical for this part of the exercise.

My calc tell me that I need the woofer ports to be within 172mm of the SB65 to maintain 1/4 wavelength @ 500hz. I believe I can get them as close as 145mm, at the start of the second flare in the pic.



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Made some headway, woofer mount for both sides printed in two parts in case I need to change Xmas clearance or port size.

Notice the m6 bolts clamping the mounts around the horn, this will take much of the woofer weight off a smaller glue/bonding area.

Next is up is die grind the woofer ports, cleanup and surface the plastics, mount everything with 3mm Eva gaskets and mount all the drivers.

Then fire it all up without enclosure using minidsp 2x4 and 4xTPA3255.
 

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Well that took most of the day but we have a single completed and ready for testing unit.

I may replace some of the 3mm gaskets with 1 or 1.5mm but enough for today.

Cold beer is calling.
 

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