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Directiva r2 monitor prototype build

Nice DI curve...
BTW the spl range in that heatmap is quite wide - you might like to narrow it down a bit, since there's hardly any information below "green" (I'm using smth like 50-90 FWIW).
Did you measure some 2- or 3-slot variant ? IME, the 2-slot sim is nicer than 1-slot - haven't measured any yet.

I have posted heat maps with different scaling and realized it could be misleading and am sticking to the +/-180 that Amir uses. The latest r2 is a single slot.

More generally, would you mind sharing some of the things you learned about correlation, or lack thereof, between sim and measurements?
IOW, what makes sim predictive or not, and what did you find discrepancies, if any, to originate from ?
(Asking for a friend ;))

The sims were done by @ctrl and the correlation is ok so far. Expect they will get better as I tweak the crossover but also may be my new test rig. Need to review with @ctrl but he has been busy lately. I also think the ultimate comparison will be with the Klippel. My current target is to refine the damping material type and quantity. I also am bit further challenged as I lack a baseline passive resistance design for comparison.
 
Was referring not to +/- 180° angle - though +/- 90 might be more revealing of small kinks - but to SPL scale.
Yeah, damping material choice and dosage seems to be among the tricky steps along the way... Since you don't really know where to start, it is a bit of shooting in the dark - hope sims provide a relevant pattern as to where to go from initial random hit & miss ;)
 
Was referring not to +/- 180° angle - though +/- 90 might be more revealing of small kinks - but to SPL scale.
Yeah, damping material choice and dosage seems to be among the tricky steps along the way... Since you don't really know where to start, it is a bit of shooting in the dark - hope sims provide a relevant pattern as to where to go from initial random hit & miss ;)

Gotcha. Have only played with the angle scaling and found it could be misleading. Not sure about SPL scale setting as did not choose. In the settings, it is set to standard 50 dB range. The sims cut off at 10 kHz but seem to be much more detailed than the actuals. I do not know if damping is fully simulated. I do not think so…

After I get the woofer spin, plan to baseline the sealed enclosure. This should help give us an idea of the enclosure’s contribution to directivity.
 
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IME you need to factor in the damping into the simulated model, otherwise you end up with a quasi-dipole in the lower range instead of a cardio pattern. Point is, when you reach the sweet spot in terms of simulated damping (about 1/3rd of the "wall impedance" range AFAICT) you still have no clue about which stuff in which quantities will get you there IRL :rolleyes:
 
Nice DI curve...
BTW the spl range in that heatmap is quite wide - you might like to narrow it down a bit, since there's hardly any information below "green" (I'm using smth like 50-90 FWIW).
Did you measure some 2- or 3-slot variant ? IME, the 2-slot sim is nicer than 1-slot - haven't measured any yet.
btw, post #179 is the original 4 slot design. Is just done on a more professional test rig and so am not sure if that is the main diff or not. I went to baseline with closed box and things really went awry. Have weekend guests so will be Monday before I can get back to it.
 
Well ended up tinkering with Denotiva as I realized I was testing r2 with the same test fixture and it is wider than the speaker. Since I had built a new turntable, needed a new fixture to test r2 on it. I also switched to my PVC pipe stand to help ensure the stand is not influencing the results. If all goes well, will have new baselines over the weekend and resume testing damping alternatives.
 
Well ended up tinkering with Denotiva as I realized I was testing r2 with the same test fixture and it is wider than the speaker. Since I had built a new turntable, needed a new fixture to test r2 on it. I also switched to my PVC pipe stand to help ensure the stand is not influencing the results. If all goes well, will have new baselines over the weekend and resume testing damping alternatives.
Is there any news? I am very interested in this project!
 
Is there any news? I am very interested in this project!

Am still juggling other projects and have had a couple of family weddings too. The work I am doing on testing various damping materials is partly to help better understand what damping (and how much) is best for r2.
 
So, r2 is next on my queue. At this stage, my plans are to wrap up the monitor in its original form as a small 2-way. I had plans to make it a small 3-way but seems best to stay with the bass module/subwoofer arrangement. Frankly, the original premise of using a passive resistance enclosure has proven to be more work than I thought. I have always build simplicity as a goal and I now see this could be a more difficult design for others to replicate.

In the team design discussions, a simpler approach to getting better directivity was proposed. This involves using a coaxial driver. As some of you know good coaxial speakers are not that common and the recommended one had availability issues so I shelved the idea. Since then, I have found a supplier and am getting samples to try. This design would have a simpler cabinet and more readily take on a woofer too. Am targeting something KEF R3-like and possibly an LS50-based approach too.

More to come but want to finish up r2 first.:)
 
Makes sense! Could you post the designs for the passive resistance enclosure that you ended up not moving forward with? I don’t think the exact measurements are in the thread (though I could be wrong)
 
Makes sense! Could you post the designs for the passive resistance enclosure that you ended up not moving forward with? I don’t think the exact measurements are in the thread (though I could be wrong)

I thought they were too, but after wrangling over slots and a cabinet with larger woofer, does not appear they got posted externally. Here is a detailed image...

1729974123819.png
 
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