Greetings @mabat, others who printed A520G2, or have experience with printing,,
my friend was volunteered to print the above-mentioned wave-guide; however as neither he or I have much experience beyond creating an STL file and accepting the printer's software default values, I have come questions:
1. The printer bed is 12 x 12 in, is it large enough for the print?
2. What would be a preferred material and parameters, e.g., fill, print speed, nozzle, and the like for a good result?
3. How much of the pint material will be needed, so that we do not run out of it?
4. Any other suggestions or advise to issues I am missing?
I also have some question regarding the STL file(s) provided by @mabat, since I have an unusual driver - a replica of an RCA-1428. Replica in the sense that the field coil, the phase plug, the phase plug/diaphragm/voice coil assembly, and the magnetic circuit are the same, but the overall construction is different, see attached picture. As a consequence, the mounting screw pattern is non-standard.
5. As this is 1.4 in exit flush with the front face, is there an adapter that might fit, or will I have to somehow design and print my own?
6. If the former, is there some application that allows modifying the adapter’s STL file to account for the non-standard interface? I tried several times to import an STL file to Solidworks and convert it, but the results were inconsistent; for some files all the features were recognized, for others only certain features were recognized.
7. If the latter, did @mabat posted some guidance, I have not found anything? Or, is it as simple as extending the wave-guide curve to 1.4 in diameter with 0 deg entrance angle?
Kindest regards,
M
my friend was volunteered to print the above-mentioned wave-guide; however as neither he or I have much experience beyond creating an STL file and accepting the printer's software default values, I have come questions:
1. The printer bed is 12 x 12 in, is it large enough for the print?
2. What would be a preferred material and parameters, e.g., fill, print speed, nozzle, and the like for a good result?
3. How much of the pint material will be needed, so that we do not run out of it?
4. Any other suggestions or advise to issues I am missing?
I also have some question regarding the STL file(s) provided by @mabat, since I have an unusual driver - a replica of an RCA-1428. Replica in the sense that the field coil, the phase plug, the phase plug/diaphragm/voice coil assembly, and the magnetic circuit are the same, but the overall construction is different, see attached picture. As a consequence, the mounting screw pattern is non-standard.
5. As this is 1.4 in exit flush with the front face, is there an adapter that might fit, or will I have to somehow design and print my own?
6. If the former, is there some application that allows modifying the adapter’s STL file to account for the non-standard interface? I tried several times to import an STL file to Solidworks and convert it, but the results were inconsistent; for some files all the features were recognized, for others only certain features were recognized.
7. If the latter, did @mabat posted some guidance, I have not found anything? Or, is it as simple as extending the wave-guide curve to 1.4 in diameter with 0 deg entrance angle?
Kindest regards,
M
Hi mjhara,
the driver was developed by my friends as a replica of the RCA driver I mentioned above, and was produced, more or less for custom systems, by my friends' company Cogent. As it differs from the original it was designated as DS-1428, you will find more details by searching. The original DS-1428, and, as to the best of my knowledge, now a derivative is also used by OMA in some of their speakers.
Kindest regards,
M
the driver was developed by my friends as a replica of the RCA driver I mentioned above, and was produced, more or less for custom systems, by my friends' company Cogent. As it differs from the original it was designated as DS-1428, you will find more details by searching. The original DS-1428, and, as to the best of my knowledge, now a derivative is also used by OMA in some of their speakers.
Kindest regards,
M
@mefistofelez that is amazing - I saw a little snipped about those drivers on a website and they look pretty incredible. OMA speakers are actually the ones that got me into the diy hobby because I could never afford their speakers, so I’ve been on a mission to figure out how to build them on their own. If you want help with an adapter just dm me - I’d be happy to help adjust the ath adapters to your driver if @matbat you don’t mind
Hi @mjhara,
On a slightly different note, I found a link that shows one of the best systems that I have ever heard. Steve was a musician, a professional piano tuner for inter alia the Crystal Cathedral, and as such had a fine ear. But the main reason for posting the link is that when you scroll down, you will see the construction of the driver. https://audiofederation.com/hifiing/2006/Cogent/500/
BTW, what is dm? Is that the same as pm?
Kindest regards,
M
I really appreciate your offer.
On a slightly different note, I found a link that shows one of the best systems that I have ever heard. Steve was a musician, a professional piano tuner for inter alia the Crystal Cathedral, and as such had a fine ear. But the main reason for posting the link is that when you scroll down, you will see the construction of the driver. https://audiofederation.com/hifiing/2006/Cogent/500/
BTW, what is dm? Is that the same as pm?
Kindest regards,
M
the difference explained:
a pm is a message you write to another user on a message board, and a dm is a message you write to another user on social media.
yours truly
p.s.: quite the esoteric driver
Only the last one added to the full ring will tell you how accurate they are 🙂
But it looks perfect indeed, congrats.
If you provide the numbers, I can make a new adapter, even if for just this driver, it's no big deal.
The exact adapter shape can make surprisingly big differences. I always do this by running an optimization algorithm, it's unlikely to find the best one manually, there are still several degrees of freedom. The only problem is that even for a known exit angle and diameter, the internal expansion is typically unknown, so there will always be a bit of luck needed.
Anyway, do it as recommended, that is assemble the full petal ring at once with a slow (and preferably filling) glue. That's the best way to overcome any geometrical imperfections. The worst way is probably to make two halves glued separately and then try to fit them together (been there).
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Will do it , just reflecting if I should simply put more infill in the petals , without hassling myself with something to pour inside, on the horn mouth is doable , but the petals are pretty thin, and everything would weight a lot more
I would keep the petals lightweight and only cover the whole waveguide with a coat of something that will make it stronger.
Thank you, I was asking because I didn’t know how to proceed and if it would have some noticeable impact on the resonances of the horn, I might as you suggested keep the petals lighter , and fill the horn and the extended throat with something because it is Easyer .
As for the throat parts, it's probably a good idea to make them as rigid as possible. That means a heavier infill, and if you can print using some more sturdy filaments (have the printer and the nozzle), I wouldn't hesitate to do so. For the base just some moderate infill is probably good enough, provided the petals are light.
So, there's an easy pattern - go from heavy and more solid to something more lightweight and well-damped as you go from throat to mouth.
So, there's an easy pattern - go from heavy and more solid to something more lightweight and well-damped as you go from throat to mouth.
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I will follow your tips! As I have the printer itself I can make multiple version and experiment some stuff!
Hello, yesterday I found some time to make a measurement with Akabak. I was already despairing with gmsh and finally managed to control the resolution of the mesh.
I made a measurement with the waveguide from mabak with a housing.
Unfortunately I get some artifacts or let's say results that I can't explain.
Does anyone of you have an idea why the frequency response above 15kHZ looks like this? Is it a flaw in the cabinet design? Is it due to the mesh resolution or the Akabak sim setup?
I am grateful for any help
I made a measurement with the waveguide from mabak with a housing.
Unfortunately I get some artifacts or let's say results that I can't explain.
Does anyone of you have an idea why the frequency response above 15kHZ looks like this? Is it a flaw in the cabinet design? Is it due to the mesh resolution or the Akabak sim setup?
I am grateful for any help
This typically happens when the mesh is too coarse for that frequencies. I would maybe suggest to distribute the mesh density more evenly across the front face of the enclosure. It seems very high near the tweeter, this may not be necessary. Try to spread it more evenly.
Overall, I'm a bit surprised how worse it gets in such enclosure. At least it seems worse.
Overall, I'm a bit surprised how worse it gets in such enclosure. At least it seems worse.
Hi @sheeple,
thank you for the explanation of dm and pm. So, from the practical perspective, they are the same.
Indeed, very esoteric driver. The original design was tested on Plain wave tube (PWT) between 100 - 13,000 Hz.
Hi @mabat,
Kindest regards,
M
thank you for the explanation of dm and pm. So, from the practical perspective, they are the same.
Indeed, very esoteric driver. The original design was tested on Plain wave tube (PWT) between 100 - 13,000 Hz.
Hi @mabat,
Thank you very much for the offer. Although it may not be a big deal for you, it is a big deal for me because as I understand from following this thread;
Regarding the "internal expansion" I have an accurate CAD drawing of the phase plug, so if you could advise, how to calculate the expansion, and it would be helpful, I could do it.
Kindest regards,
M
That would be very interesting to find out. I could then add this segment into the model to see what effect it has.
You would need to calculate the areas of the air channels(s) at least at a few different distances from the diaphragm towards the exit - the more data points the better.