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Multi-Way Conventional loudspeakers with crossovers

Nexus - World's Easiest Controlled Directivity Loudspeaker
Nexus - World's Easiest Controlled Directivity Loudspeaker
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Old 15th January 2020, 03:40 AM   #71
Patrick Bateman is offline Patrick Bateman  United States
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Here's my Waslo Cosynes, with their 24" waveguide, and the polar response I measured.

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Here's my Kali Audio LP6, with their 6" waveguide, and the polar response I measured. This iteration of the speaker has a 4.5" roundover on each side.

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Here's Nexus Three, with it's 21" waveguide. These measurements show the polar response, the phase and frequency response, and the distortion.

The measured response of Nexus Three ins't perfect, but it's pretty good, IMHO. I think I can improve the response by deadening the waveguide, sealing it, and putting it on a baffle.

It seems to be doing what it's supposed to be doing, which is provide performance comparable to the Waslo Cosynes in a smaller package.

Next up... need to put it on a baffle.
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Old 15th January 2020, 03:48 AM   #72
Patrick Bateman is offline Patrick Bateman  United States
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My waveguide is fairly close to the JBL 4367.

Something that I discovered, after WAY too much trial and error, is that sometimes the *horizontal* polars get better when you 'squash' the horn on the vertical axis.

I think what's happening when you do that, is that when the horizontal beamwidth is very large, the wavefront simply can't see the walls at all. In my measurement of the Cosyne you may notice this; see how the waveguide is basically omnipolar in the octave and a half from 4500hz to 13500Hz? I think what's happening there is that the wavefront can't "see" the waveguide walls.

What's interesting about this is that a great deal depends on the wavefront shape at the exit of the compression driver. For instance, if the exit of the compression driver has a diverging wavefront, the wavefront is more likely to be constrained by the walls of the waveguide. If the compression driver has a converging wavefront, the wavefront is LESS likely to be constrained by the walls of the waveguide.

To make a long story short: I think that "squashing" the waveguide vertically is improving the horizontal polars.

The waveguide was designed with ATH4.

Last edited by Patrick Bateman; 15th January 2020 at 03:50 AM.
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Old 15th January 2020, 03:54 AM   #73
Patrick Bateman is offline Patrick Bateman  United States
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Here's the response of the midrange and the tweeter, with the xover and the EQ.

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Here's the response of the midrange and the tweeter, with xover on the tweeter and no EQ on either driver. You can see that the compression driver is REALLY efficient. I'm padding the tweeter down by 8dB to match the midrange.

Note all of these are without a baffle. Things will be better once I put everything in a box.
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Old 15th January 2020, 03:58 AM   #74
bwaslo is offline bwaslo  United States
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Nexus - World's Easiest Controlled Directivity Loudspeaker
Nexus three looks really good, natural directivity down to 500Hz. Might do lower if the drivers could go down there.
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Old 15th January 2020, 04:52 AM   #75
Beau is offline Beau
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What mid is in this version Patrick?
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Old 15th January 2020, 05:15 AM   #76
Patrick Bateman is offline Patrick Bateman  United States
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Quote:
Originally Posted by bwaslo View Post
Nexus three looks really good, natural directivity down to 500Hz. Might do lower if the drivers could go down there.
It'll use the same trick as your "Small Syns." Basically wrap the woofers around the waveguide.

Click the image to open in full size.

Click the image to open in full size.

I did this with Nexus One, and it worked nicely. You can see that my waveguide suffers from the issue I described earlier today, basically the waveguide is expanding so fast, the wavefront can't "see" the walls, causing the very wide beamwidth in the octave from 5khz to 10khz. It's almost like the waveguide isn't there.

Click the image to open in full size.

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I did the same with Nexus Two. It didn't work as well; basically I tried to push the midbasses further out, and by doing so, the pattern starts to beam badly in the midrange. Even worse, I wound up using six dB of EQ in the midrange to tame a peak.

Click the image to open in full size.

Click the image to open in full size.

Nexus Three is much better behaved than Nexus One or Two. Not that they're terrible, but going for a three-way seems to help.

Click the image to open in full size.

For comparison's sake, here's a SEOS 24 loaded with a BMS coax. I think this is a nice solution, but I like the Unity horn better for a couple reasons:

1) it's 4X cheaper

2) If you look at the response of the JBL M2 and the SEOS 24, they have a heck of a time controlling the polar response when the throat gets bigger than the wavefront. The beamwidth narrows dramatically. By comparison's sake, my waveguide's beamwidth is well behaved all the way to 24khz.

I think JBL understands these shortcomings, hence why they're making all these waveguides with 16mm compression drivers... which is exactly what I did.

Note that the SEOS 24 response has been normalized electronically. My response curve was trial and error, so I could do better with some additional work. And a baffle would help a lot.

Last edited by Patrick Bateman; 15th January 2020 at 05:20 AM.
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Old 15th January 2020, 05:26 AM   #77
Patrick Bateman is offline Patrick Bateman  United States
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Originally Posted by Beau View Post
What mid is in this version Patrick?
tweeter: BMS 4526HE

midrange: Celestion TF0410MR

midbass: MCM 55-1870 x 4

It should be possible to build one for around $350-$400.

The tweeter is a bit of a "splurge", at some point I'll probably figure out a crossover using a cheaper tweeter.
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Old 16th January 2020, 04:39 AM   #78
Synnove is offline Synnove
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What sort of yield did you get with printing such a large horn? Is it difficult to achieve a reliable print?

Also brings to mind an idea I've been wondering about: if you 3d printed the mouth of the horn with landings that plywood could mount to via fasteners, could you then 3d print the other sections of the horn, mounting them to the plywood with screws? I imagine this would ease the joining process as the 3d printed pieces wouldn't have to supply their own rigidity, and you could print in smaller sections for better yields.
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Old 16th January 2020, 05:17 AM   #79
BradH is offline BradH
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Looking good. Glad you went with a large format.
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Old 16th January 2020, 08:37 PM   #80
Brinkman is offline Brinkman  United States
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Nexus - World's Easiest Controlled Directivity Loudspeaker
Assuming high efficiency was a priority, do you think a larger diaphragm compression driver or two could sub for the mids? Iím thinking maybe coupled to the waveguide via something along the lines of a ribbon emulation manifold.
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