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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)

augerpro 5th April 2019 03:44 AM

Played with some Scanspeak tweeters! I measured four designs. One 5" that is basically the same as other 5" ellipticals in this thread. A 5" that has uses a 1:.80 aspect ratio. A 6" that is basically a scaled up version of the 5" ellipticals. And the Visiton WG148.

https://i.imgur.com/rbYCBHa.png?1
https://i.imgur.com/M3SdzpM.png
https://i.imgur.com/iHDTiQq.jpg

The 5" results:
https://i.imgur.com/yalMG24.png
https://i.imgur.com/FdsMjLJ.png
https://i.imgur.com/KalnxU9.png
https://i.imgur.com/Kxffugl.png
https://i.imgur.com/uKfm35q.png
https://i.imgur.com/oIE3FcP.png

The 6":

https://i.imgur.com/uRkFWgK.png
https://i.imgur.com/3gcLZ4u.png

And the Visiton WG148:

https://i.imgur.com/1T7LkNs.png
https://i.imgur.com/tvCKXXW.png

Here are pics of how I mated to the WG148. Used some bluetac to fill in gaps and seal around the interface. I don't how I could improve the situation any further.

https://i.imgur.com/c588Z3J.png

augerpro 5th April 2019 04:02 AM

The design files:

Dropbox - 6x1 A SS.stl
Dropbox - 6x1 A SS .step
Dropbox - 5x.75 A SS.stl
Dropbox - 5x.75 A SS.step
Dropbox - 5x.75 B SS.step
https://www.dropbox.com/s/qzpq1jc3p2...%20SS.stl?dl=0

mbrennwa 5th April 2019 04:46 PM

Thank you Brandon! These look rather nice! What drive voltage did you use for those measurement (I am trying to understand the SPL gain involved with these waveguides)?

augerpro 5th April 2019 05:42 PM

I'm not sure what voltage I used, but they have been calibrated to be correct +/- 1 dB at 2.83V.

Arnandsway 5th April 2019 06:50 PM

I'm alsoy trying to figure this out because tehe SB26ADC measurements show now a lower sensitivity than without a WG. Could it be because of a lower voltage?

augerpro 5th April 2019 07:31 PM

Where are you seeing this? For this run of tests, I was only able to calibrate the SPL "through the side door". Basically take a known tweeter, measure it and set the levels so that it matches factory spec. Then other measurements should be correct too, but there is some eyeballing with that original measurement. When I get my permanent setup rebuilt now that I'm back in a house, I'll redo the calibration based off a voltage.

Arnandsway 5th April 2019 07:39 PM

Awesome to hear. Thanks for all the hard work.

On page 30 I see that the sensitivity does not really reach 90 dB, with the 5" WG.

mbrennwa 6th April 2019 07:33 AM

Quote:

Originally Posted by augerpro (https://www.diyaudio.com/forums/multi-way/318190-source-waveguides-cnc-3d-printing-post5751133.html#post5751133)
Played with some Scanspeak tweeters ...
Here are pics of how I mated to the WG148. Used some bluetac to fill in gaps and seal around the interface. I don't how I could improve the situation any further.

https://i.imgur.com/c588Z3J.png

The WG148 needs some machining to fit the Scan R2904 and D6600. The Blue Tack probably gives an air-tight seal, but you won't get a nice fit of the throat to the point where the dome / ring membrane is fixed to the tweeter assembly. I'd guess the rather poor response curves you got the from WG148 are the result of this. Also take a look at this, which allowed me to get a much smoother SPL response with the WG148.

augerpro 6th April 2019 08:37 AM

Makes sense that milling the WG148 down made for better response. You could nestle that tweeter in more with no gap around the diaphragm. Without doing that I knew the response wouldn't be that good because the throat interface just looked poor to me.

mbrennwa 6th April 2019 08:34 PM

I am considering ordering a batch of the ScanSpeak 5" version A, made on a CNC machine from aluminium, black anodized. These would fit the ScanSpeak D3004/66x0 (textile and beryllium domes), the R2904 ring radiators and most likely also the R3004 ring radiator (just replace their stock face plate by the waveguide). The waveguides might possibly also fit some of the other ScanSpeak tweeters, but I have no clue what these tweeters look like when their face plate is removed.

Getting more than just a single pair for me would get the price down quite a bit. Anyone interested?


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