I'd be interested in the waveguide contour also. See how it compares with ones I've designed recently that are working well with the TW29TX. Someone posted that SB said the TX should measure the same as the BN on their waveguide. So the diaphragms must be similar. I made measurements of the TX to model in ABEC, I'll post them when I get home from work.
BTW, if someone has a TW29BN they wouldn't mind loaning me, I can verify that it measures the same as the TX on my waveguides.
Jim> if you can print, I can send you my best attempt so far, and you can compare it to the factory Satori waveguide.
Attached is the TW29TX diaphragm info. One wrinkle: where the surround attaches to the diaphragm is not at the same depth as where the other side of the surround attaches to the faceplate. So when I created the ATH model I put it at the same level, and widened the surround so that its height remained constant. Hopefully the picture describes it better than I can. I now realize I can adjust Z depth on all the source points, so I should have been able to model it more closely to what it actually is. Regardless, you see from the results that the ABEC model accords well with the actual measurements.
Attachments
Thanks, perhaps metric verniers are banned in the US
Any chance you could take (or have) a close up photo of the driver without the faceplate?
I have no 3D print capability. But the question may be moot for the next week or so... I injured my hand while installing a new exhaust hood above my stove. Stainless steel sheet metal can be sharp ... I have 13 stitches that will need about 10 days to heal. So until then I have 1 hand plus 2 functional fingers... But hey - I can still type and listen to music
... I have 13 stitches that will need about 10 days to heal. So until then I have 1 hand plus 2 functional fingers... But hey - I can still type and listen to music 
I have done more simulations. I have concluded that the differences between the donut and the bevel box are within the error bands of my measurements and simulations.
What I am showing here is a simulation using measured data from my SB34NRX75-6, MW16TX-4, and the two different waveguide enclosure options (bevel box and donut). For both cases I optimized the filter algorithms for the best compromise between Listening Window performance and PIR performance. My measurements are +/- 1dB at best, and my past experience has demonstrated that Vcad sims can match reality to within +/- 1 dB… Given this uncertainty, there is no meaniningful (i.e. measurable) difference between the two sims.
First the Bevel Box
Now the Donut
What I am showing here is a simulation using measured data from my SB34NRX75-6, MW16TX-4, and the two different waveguide enclosure options (bevel box and donut). For both cases I optimized the filter algorithms for the best compromise between Listening Window performance and PIR performance. My measurements are +/- 1dB at best, and my past experience has demonstrated that Vcad sims can match reality to within +/- 1 dB… Given this uncertainty, there is no meaniningful (i.e. measurable) difference between the two sims.
First the Bevel Box
Now the Donut
If I was optimizing in Vituix I would still pick the bevelled box every time
I wonder if there is something to be gained in the transition from woofer to mid. There is a directivity jump from 500 to 1000Hz and the dip in the woofer seems to be coming into play even though it is well down. Perhaps a problem for the eyes more than the ears but who knows without trying.
To me it seems the mid has some jump in directivity at about 600-700Hz. Looking at the mid enclosure pics I guess it's about 10" wide. Wonder if those two are related (I guess so).
Directivity spectrogram shows very sharp change in directivity -6dB line. Edge diffraction often shows even wider diffusion... The 12" woofer SB34 has a dip in on-axis response there, but it is at -25dB level... And it is most likely an artefact, reflection nulling.
How about changing one parameter at the time in simulation? Driver placement, diameter, baffle width... Cone concavity is not icluded in the sim, so it is not the full truth!
Qts - how can internal resonance affect directivity? What is "lower suspension" of a driver - spider?
How about changing one parameter at the time in simulation? Driver placement, diameter, baffle width... Cone concavity is not icluded in the sim, so it is not the full truth!
Qts - how can internal resonance affect directivity? What is "lower suspension" of a driver - spider?
I think the directivity changes in the 600Hz region are a function of the enclosure dimensions and driver size and occurs probably due to low-frequency diffraction.
We had seen similar radiation patterns and off-axis dips and peaks in the extensive set of simulations that fluid had done for my project.
For example, here: https://www.diyaudio.com/community/threads/a-3-way-design-study.376620/post-6836282
Regards
Vineeth
We had seen similar radiation patterns and off-axis dips and peaks in the extensive set of simulations that fluid had done for my project.
For example, here: https://www.diyaudio.com/community/threads/a-3-way-design-study.376620/post-6836282
Regards
Vineeth
The woofer response wiggle at ~550 Hz is a result of the near field measurement cancellation. It is not present when I make an outdoor ground plane measurement.
I was never able (willing) to lift this woofer cabinet up onto the rotating stand to perform polar measurements. I simply used Vcad to simulate the polar responses based on the NF measurements and the cabinet shape. And yes, the woofer wiggle at 550 Hz does affect the overall simulation by about 1 dB at 600-700 Hz, but it may or may not be a real.
https://www.diyaudio.com/community/threads/interesting-diffraction-effect.374851/#post-6727561
If I were to mount a recessed 6.5" driver under the tweeter, I don't think the beveled box data would look so nice. Unfortunately, my foam box prototype is not tall enough to do that experiment with the correct CTC driver spacing.
The current design concept would have the "donut" or teardrop tweeter housing mounted above and in front of the midrange enclosure. I would use digital delay to bring the two drivers into alignment. So the donut tweeter data is very representative of the final design because it will be mostly immune from the effects of cone driver diffraction.
Thank you for your thoughts, Fluid !
j.
I was never able (willing) to lift this woofer cabinet up onto the rotating stand to perform polar measurements. I simply used Vcad to simulate the polar responses based on the NF measurements and the cabinet shape. And yes, the woofer wiggle at 550 Hz does affect the overall simulation by about 1 dB at 600-700 Hz, but it may or may not be a real.
The beveled box data does look really good, but it is not entirely representative. The prototype box did not have a mid driver mounted, so it does not reflect the cavity effects that a real cone driver would introduce. We discussed this in this thread
https://www.diyaudio.com/community/threads/interesting-diffraction-effect.374851/#post-6727561
If I were to mount a recessed 6.5" driver under the tweeter, I don't think the beveled box data would look so nice. Unfortunately, my foam box prototype is not tall enough to do that experiment with the correct CTC driver spacing.
The current design concept would have the "donut" or teardrop tweeter housing mounted above and in front of the midrange enclosure. I would use digital delay to bring the two drivers into alignment. So the donut tweeter data is very representative of the final design because it will be mostly immune from the effects of cone driver diffraction.
Thank you for your thoughts, Fluid !
j.