Either VituixCAD diffraction tool, the easiest, or the Ath Mesh.Enclosure and LFSource?
What about the reflection of the low/midrange sound wave off the throat? Shouldn't it be as close as possible to the throat also for this reason? The sound emitted by the midrange ports doesn't propagate only towards the mouth.
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I think that something similar in size to the waveguide, or a little smaller, will always turn out as best. That's a proven rule of thumb. Even the smallest of the Gen horns still has more than 6 dBDI around 600 Hz, the bigger ones are like 7.5 dB. You need something of a comparable size to keep up.
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I printed the A520G2 and T520-25-STD-1 and here are the results with BMS 5530ND and B&C DE360 (4 ms gate, no smoothing):
My conclusion is that the 5530ND is smoother and has better output around 1 kHz. Distortion is very similar.
@mabat: Could your DE360 be damaged somehow?
One note: I noticed during assembly that the petals had lifted off of the build plate at the end closest to the throat. This has probably affected the final shape a bit and I'll try printing a new set.
My conclusion is that the 5530ND is smoother and has better output around 1 kHz. Distortion is very similar.
@mabat: Could your DE360 be damaged somehow?
One note: I noticed during assembly that the petals had lifted off of the build plate at the end closest to the throat. This has probably affected the final shape a bit and I'll try printing a new set.
I can redo my measurement of the DE360, yours is quite different indeed. What surprises me are all the small wiggles in the HF response of the 5530ND. I never saw this in any of my (gated) data. What would be your explanation?
The on-axis dip around 2.2k in the response of the DE360 is also strange - this shouldn't depend on a driver, IMO. Would be interesing to trace this back.
- Otherwise the 5530 looks pretty similar to my measurements of the 4554 in A520G2 / T520-36-STD-1.
The on-axis dip around 2.2k in the response of the DE360 is also strange - this shouldn't depend on a driver, IMO. Would be interesing to trace this back.
- Otherwise the 5530 looks pretty similar to my measurements of the 4554 in A520G2 / T520-36-STD-1.
Comparable size of LF to the horn itself would dictate a 15". I am not happy with that for a XO of 600Hz.
What about a smaller one in a waveguide for best match? For such low frequency quite easy. I remember there is a tool (it was named ATH or so...) that makes it very comfortable 🤣
In that case it would be cool to match it to the HF horn. Like theese waveguides...just with horns. You get the idea?
What about a smaller one in a waveguide for best match? For such low frequency quite easy. I remember there is a tool (it was named ATH or so...) that makes it very comfortable 🤣
In that case it would be cool to match it to the HF horn. Like theese waveguides...just with horns. You get the idea?
Yes, I guess that would work pretty much the same, maybe better. I once considered this an option myself, then forgot about it. It's just a lot more laborous. What woofer size would you use then?
Actually, this would be a waveguide more than a horn 🙂
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I'm guessing that it's the warped print causing a bad transition between the base and the petals. It could also be the table the waveguide was resting on I guess. I'll try a better measurement setup next time.
How much a bad transition if I may ask? Will a mm of edges not meeting perfectly make for such a result?
20k -> 17mm ....
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20k -> 17mm ....
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A horn is a design that optimises on output level while a WG is one that optimise on directivity.
?
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There's no border, really. Call it what you like, it's both all the time.
In my mind the only difference is the objective when designing it. A horn is to amplify sound, while a waveguide is to control directivity.
mabat: Here are some measurements that I hope help you design a 5530ND version of the extended adapter. Photos for reference, not actual measurement.
The end of the throat connected to the diaphragm is around 19.5 mm and at the start (where the channels come in from the sides) it's 16.3 mm.
The hole in the magnet assembly closest to the phase plug is 20 mm:
The opening on the other side, where it meets the waveguide is 24.8 mm (not 25.4):
The thickness of the entire magnet assembly is 20 mm:
There is also a 0.7 mm step where the foam gasket (on top of bug screen) was placed.
A photo down the throat after removing bug screen:
This photo also shows the 0.7 mm step for the foam gasket.
mabat: Here are some measurements that I hope help you design a 5530ND version of the extended adapter. Photos for reference, not actual measurement.
The end of the throat connected to the diaphragm is around 19.5 mm and at the start (where the channels come in from the sides) it's 16.3 mm.
The hole in the magnet assembly closest to the phase plug is 20 mm:
The opening on the other side, where it meets the waveguide is 24.8 mm (not 25.4):
The thickness of the entire magnet assembly is 20 mm:
There is also a 0.7 mm step where the foam gasket (on top of bug screen) was placed.
A photo down the throat after removing bug screen:
This photo also shows the 0.7 mm step for the foam gasket.
I would also need to know the depths of all the different sections that have different wall slopes.
- Could you perhaps try to make something like this?
I had to do this with the 4554 - to print a few iterations of such "template" and only after it fitted perfectly I could continue, as the first try based on the measured numbers was still not accurate enough.
- Could you perhaps try to make something like this?
I had to do this with the 4554 - to print a few iterations of such "template" and only after it fitted perfectly I could continue, as the first try based on the measured numbers was still not accurate enough.
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I'll try!
The red line is 10 mm long (that's how deep you go, right?) and the green line is 11.5 mm long.
I assume that everything that has to do with the membrane side is identical to the 4554.
The red line is 10 mm long (that's how deep you go, right?) and the green line is 11.5 mm long.
I assume that everything that has to do with the membrane side is identical to the 4554.
Please do, it would made the process as effective as it gets. The 4554 adapter goes to about half the red line I think, and it has an angle change (it ends at approx. ø17 mm inner diameter). It partly covers the diaphragm assembly. The deeper the better, I would think.
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Would you say there is an angle change between the conical section in the diaphragm assembly and the conical section through the magnet for the 4554? Looking at the 5530ND I can't see any of that. This is what I would say the cross-section looks like:
I believe you could live with the 0.1-0.2 mm gap above the red part and thereby not make the geometry more complex by avoiding the step:
I believe you could live with the 0.1-0.2 mm gap above the red part and thereby not make the geometry more complex by avoiding the step:
There's definitely an angle change in 4554 (and probably even bigger in 4555). But that's not important.
As you draw it, this should be perfect. And if you were actually able to move the bottom end even lower / deeper that tiny extra bit, it could be even better. 👍
As you draw it, this should be perfect. And if you were actually able to move the bottom end even lower / deeper that tiny extra bit, it could be even better. 👍