Ribbon Unity Horn

[Patrick Bateman]

Here's the STL print for this waveguide

There's some plastic on the bottom of the waveguide that must be cut off with a scissors when it's finished. The plastic is there to keep the print from coming off the print bed

You'll need two prints to make one waveguide. Just flip one upside down and then epoxy the two of them together.

I took a much different approach with this waveguide, than with most of my waveguides. This waveguide is designed to be printed with 100% infill. A lot of my old waveguides had very thick walls, and sometimes I even printed them with zero infill. The reason that I went the opposite direction with this waveguide, is that I found that the hot Vegas sun was warping my waveguides, even when I printed them out of PETG.

If you want to go the extra mile, you can bake the print in salt, which is what I did:

 

[Patrick Bateman]

The tweeter in this speaker is an Airborne RT-5002

The woofer is a Dayton DC130B-4

Airborne, RT-5002 - Meniscus Audio

 

[Patrick Bateman]

As of last year, Mabat's brilliant "ATH" software can simulate ribbons.

So I want to see how a BG NEO3 behaves on a waveguide.

Attached are pics.

Here's the details on the waveguide:


C:\Users\johnv\Downloads\ath-beta-4.9>ath.exe demos\07012023-1.cfg

Ath 4.9.0-pre-release-221114
-------------------------------------------------
Free version for personal non-commercial use
Marcel Batik <author@at-horns.eu>, 2018-2022
-------------------------------------------------

-destination directory: c:\Users\johnv\Downloads\Ath-beta-4.9\output\\07012023-1
-calculating profiles
-creating 2-profile geometry
adapter aspect ratio: 0.667 (1.500)
constraints for k = <0.1,100>:
min.diagonal angle: 41.55 deg
->horizontal angle: 26.18 - 14.71 deg
->vertical angle: 36.40 - 48.13 deg
-writing ABEC project
-writing geo file bem_mesh.geo
-average mesh throat angle: 0.000 deg
-running 'c:\Users\johnv\Downloads\gmsh-4.8.4-Windows64-sdk\bin\gmsh bem_mesh.geo -'
Info : Running 'c:\Users\johnv\Downloads\gmsh-4.8.4-Windows64-sdk\bin\gmsh bem_mesh.geo -' [Gmsh 4.8.4, 1 node, max. 1 thread]
Info : Started on Sat Jul 01 03:04:24 2023
Info : Reading 'bem_mesh.geo'...
-running 'c:\Users\johnv\Downloads\gmsh-4.8.4-Windows64-sdk\bin\gmsh mesh.geo -'
Info : Running 'c:\Users\johnv\Downloads\gmsh-4.8.4-Windows64-sdk\bin\gmsh mesh.geo -' [Gmsh 4.8.4, 1 node, max. 1 thread]
Info : Started on Sat Jul 01 03:04:27 2023
Info : Reading 'mesh.geo'...
Done.

Device width x height = 302.52 x 300.36 mm (11.910 x 11.825")
Mouth aspect ratio = 1.007 (0.993)
Device length = 70.00 mm (2.756")

 

[Patrick Bateman]

Here's the measured polar response of the KEF R3, courtesy of erinsaudiocorner

Here's the predicted polar response of my waveguide from the last post. I intentionally used the KEF as a "goal" largely because it's well regarded. My waveguide goes about an octave lower because my enclosure and waveguide combo is nearly twice as wide as the KEF. Beamwidth is about the same: about 120 degrees.

 

[Patrick Bateman]

Attached is the normalized and unnormalized horizontal response of the waveguide from post 83

I think it looks pretty good. It doesn't have a crazy amount of gain, because the waveguide angle is wide (120 degrees) and the throat is relatively large. But there's still a solid six decibels of gain on axis, from 300Hz to 7khz. That should improve the dynamics and power handling of the NEO 3, which is already quite dynamic due to it's 90dB sensitivity.

Next thing I want to check out, is what happens if I make the baffle very tall, similar to the KEF Blade