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-   -   Open source Waveguides for CNC & 3D printing! (https://www.diyaudio.com/forums/multi-way/318190-source-waveguides-cnc-3d-printing.html)

ggetzoff 28th October 2018 01:49 PM

Brandon,

It seems like smaller radii domes benefit the most from a wg (i.e. 90 degree to flatish transducers), Is that correct? If that's the case, the phenomenal ring domes would potentially be the best candidates, correct?

Cheers,

Greg

augerpro 28th October 2018 06:27 PM

The SB21 dome is actually nearly a half-circle, the SB26 is much flatter, so it didn't quite turn out that way. Ring radiators work well, but I think that has more to do with the phase plug of the Scans and Vifa. I'm personally not a big fan of the XT25, had it in my theater speaker for years, so I haven't bothered with it. The Scans would be more interesting.

mbrennwa 28th October 2018 07:01 PM

Quote:

Originally Posted by augerpro (https://www.diyaudio.com/forums/multi-way/318190-source-waveguides-cnc-3d-printing-post5585510.html#post5585510)
The Scans would be more interesting.

You will have one in your hands soon (Scan R2904/7000). It should be on the way to me... in the meantime you could send me your address details by PM so that I can send it to you.

augerpro 18th November 2018 04:18 AM

More waveguides results! I just changed my soundcard so I can now measure out to 48khz and capture these metal dome breakups a bit better. I'll keep updating over the next few days as I have a lot of waveguides. Up first are the 5" waveguides.

I knew the CSS LD22 could measure a lot better with a smaller throat, and these results definitely prove that out:

https://i.imgur.com/lM5l642.png

Looks damn good!

Next are the RST28's. First the fabric dome with no phase shield:

https://i.imgur.com/fGVipUy.png

Now the RST28A with the standard .25" diameter phase shield I've been using, it is about 1/8" from the dome:

https://i.imgur.com/UOqe7AY.png

Holy breakup! I think there is room to play with the PS to hopefully get a null to land on the breakup. I won't post all of the variations I tried, but I moved the PS closer and farther away, used a .47" dia PS, added an outer ring and played with ring size. The ring looks to be an improvement when comboed with the .25" dia PS, not so much when comboed with the .47" dia PS though it was the best result of any other .47" variant. Here are the best three results of the experiements I did:

https://i.imgur.com/PF3oZz5.png
https://i.imgur.com/W86MrWP.jpg?2

And also the RST28A without a phase shield:

https://i.imgur.com/nefT7PA.png

Will get the SB21 and SB26's up tomorrow, I now have three variants of the SB26: aluminum, ceramic/anodized Al, and fabric. I also have some 4" and 8" waveguides.

augerpro 18th November 2018 02:02 PM

BTW, does anyone know how to setup wavelet analysis in SE?

​​​​​​​https://i.imgur.com/M8xHpSJ.png

next667 18th November 2018 03:29 PM

thanks!
Looking forward to sb26 fabric on 8" wg test :) Should be relatively high sensitivity result (with its top end peaking),narrow surround and high xmax. Could you maybe run HD sweeps for some of the bigger wg combos please?

augerpro 18th November 2018 04:52 PM

Quote:

Originally Posted by next667 (https://www.diyaudio.com/forums/multi-way/318190-source-waveguides-cnc-3d-printing-post5605112.html#post5605112)
thanks!
Looking forward to sb26 fabric on 8" wg test :) Should be relatively high sensitivity result (with its top end peaking),narrow surround and high xmax. Could you maybe run HD sweeps for some of the bigger wg combos please?

I don't have my old setup that was surrounded by absorption to clean up the HD sweeps, so I probably won't be doing that now. Maybe next summer when I build another monster baffle in the garage.

ergo 18th November 2018 05:19 PM

Keep up the good work Brandon. This is all most interesting and enlightening :)

augerpro 18th November 2018 08:38 PM

Somehow I managed to not get printed the newest 5" and 8" for the SB26 :( But since I have three dome variants now and can measure out to 48khz, I thought I'd revisit the 5" vG and 8" vC. None these will have phase shields as I already cut them off months ago.

First is the fabric dome SB26STAC:

https://i.imgur.com/Qg5OMG4.png
https://i.imgur.com/nmdxzEB.png

Aluminum done SB26ADC:

https://i.imgur.com/n3cYb0Z.png
https://i.imgur.com/f7eqo8e.png

Ceramic dome SB26CDC:

https://i.imgur.com/6M9eOz4.png
https://i.imgur.com/41vXnrJ.png

I wanted to revisit using an ellipse as the profile for the flare. Like this:

https://i.imgur.com/VTTlNfw.png
https://i.imgur.com/m4OnbSc.png
https://i.imgur.com/LBHCTwy.png
https://i.imgur.com/CpwUXfe.png
https://i.imgur.com/LxKn7Pb.png
https://i.imgur.com/CLY4xBs.png

Interesting results, I'll have to dig into this later.

Next is the little SB21SDC:

https://i.imgur.com/3vcVJwX.png

And last, the 8" RST28 designs:

https://i.imgur.com/qUm340U.png
https://i.imgur.com/27ZMtpo.png
https://i.imgur.com/aNb2qKl.png

Up next will be some 4" designs. I see some value in a small waveguide used to cross higher to a smallish mid. Benefits: still matches mid directivity, allows mid to cover much of vocal range without a wonky polar response, acoustic centers align.

After that I need to play with phase shields in shims and see what happens. I'd really like to get lucky and notch out those metal dome breakups.

augerpro 18th November 2018 08:52 PM

Noticed the fabric SB26 has a small felt ring on top of the pole piece, while the metal versions do not:

https://i.imgur.com/CfcrwLC.jpg?1

Let's see if this new phone can capture these waveguides better:

https://i.imgur.com/IvmTzPM.jpg?2
https://i.imgur.com/GudbSv7.jpg?2


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