Hello pelanj,
The model I'm sharing with people are generic, and the idea is to giver user freedom to adjust the models to any driver size like from 6" to 21", so the user just need to adjust the dimensions.
Almost all current available models use parabolic as horn flare so they are straight panel, see below a post from @David McBean when I was asking him about non parabolic flares.
"Any rectangular cross-section horn can have two parallel sides, it's just that with a parabolic flare horn the other two non-parallel sides will be straight panels because the overall area expansion rate of a parabolic horn is linear. For all other horn types, if two sides are parallel then the other two non-parallel sides will be curved rather than straight, to maintain the required area expansion rate of the horn in question."
https://www.diyaudio.com/community/threads/hornresp.119854/page-659#post-7155609
From my side, I kind of polynomial equation would need to be defined to better fit curved horns, but I don't know if it would be reliable. Currently there are two models available that could benefit from this approach, the Altec816, but rather then use curved flare I user 3 parabolic flare in alternative to the original project and the ModernDualVB2 witch is currently using exponential flare.
Probably I'm not following this route anymore.
For sure FreeCAD can import a set of points exported from hornresp to draw a horn profile, probably it will require a macro to do it. The thread below might be a good start for you.
https://forum.freecadweb.org/viewtopic.php?f=8&t=5176
also this one
https://forum.freecadweb.org/viewtopic.php?t=7828
The model I'm sharing with people are generic, and the idea is to giver user freedom to adjust the models to any driver size like from 6" to 21", so the user just need to adjust the dimensions.
Almost all current available models use parabolic as horn flare so they are straight panel, see below a post from @David McBean when I was asking him about non parabolic flares.
"Any rectangular cross-section horn can have two parallel sides, it's just that with a parabolic flare horn the other two non-parallel sides will be straight panels because the overall area expansion rate of a parabolic horn is linear. For all other horn types, if two sides are parallel then the other two non-parallel sides will be curved rather than straight, to maintain the required area expansion rate of the horn in question."
https://www.diyaudio.com/community/threads/hornresp.119854/page-659#post-7155609
From my side, I kind of polynomial equation would need to be defined to better fit curved horns, but I don't know if it would be reliable. Currently there are two models available that could benefit from this approach, the Altec816, but rather then use curved flare I user 3 parabolic flare in alternative to the original project and the ModernDualVB2 witch is currently using exponential flare.
Probably I'm not following this route anymore.
For sure FreeCAD can import a set of points exported from hornresp to draw a horn profile, probably it will require a macro to do it. The thread below might be a good start for you.
https://forum.freecadweb.org/viewtopic.php?f=8&t=5176
also this one
https://forum.freecadweb.org/viewtopic.php?t=7828
Hi LordSansui
I stumbled upon your work and it quite impressive.
If I may suggest another design for your collection then the Altec 817. It is the Voice of the Theater horn.
I stumbled upon your work and it quite impressive.
If I may suggest another design for your collection then the Altec 817. It is the Voice of the Theater horn.
Hello 27ph, thank you, I would be happy if it can serve you in any means.
I would not say the models are mine, they were made using opensource tool and they are freely available, people can use, share, modify, publish. The only think I ask is if people build the box, share the data with others, so everybody won.
I found the attached plan for the Altec 817, is it OK to use it as reference with the JBL 2226 driver?
Do you prefer to have a single driver model or as the original design with 2-drivers model?
Attachments
Why JBL drivers are so expensive if they are not powerfull by today standards, the 2226 is rated at 600 watts and Xmax is only 7.6
Thank you, probably the original box were sold using this driver, but now a days I'm not sure if using Altec 815 make sense. Can you still find brand new Altec 815 in the market? is it a good option?
JBL 2226 is still on sell
https://www.parts-express.com/JBL-2226H-15-High-Power-LF-Driver-8-Ohm-294-470?quantity=1
https://www.parts-express.com/JBL-2226H-15-High-Power-LF-Driver-8-Ohm-294-470?quantity=1
570+ usd for a 7.6 xmax driver.....
you can get this for less with more power handling and more xmax
Once 27ph asked for a new model, I'm trying to understand his needs in order to satisfy it. The models available for download are just a starting point, not the destination 🙂 The major part of the models use Snake HPX2150 that isn't available anymore in Brazilian Market.
Backing to Altec 817, I read that some guys liked the performance of JBL 2226 in the original design, so it can be a safe place to start.
If you think about the original design, those new model may not work well. If you think about adjust the design to the specific driver, so you can work.
Backing to Altec 817, I read that some guys liked the performance of JBL 2226 in the original design, so it can be a safe place to start.
If you think about the original design, those new model may not work well. If you think about adjust the design to the specific driver, so you can work.
My interest in Altec 817 is that I have four drivers that I would like to see how would perform in that cabinet configuration. They are smaller (10" Volt B2500.4) But I hope to reach 50 Hz (at least) but more interesting to me is the performance upwards as I would like the (mid)woofers to work as far as possible.
To be perfectly honest, the tool may be beyond my competency to use. But maybe with a working 817 model I could start tweaking in Hornresp.
Please don't see this as a priority, I just really dig the 817 for some reason.
To be perfectly honest, the tool may be beyond my competency to use. But maybe with a working 817 model I could start tweaking in Hornresp.
Please don't see this as a priority, I just really dig the 817 for some reason.
Nice, you are going to be able to do it, see attached the model request. Due to the lacking information for Altec817 it was needed to guess some dimensions, also for the JBL2226H driver some of the T/S parameter I used was from datasheet and others were estimated from hornresp. Attached you can also find the SPL curve I achieve, I didn't tried any otimization. The model is dual driver as the original one, but the horn is made using tree parabolic segments instead of curved profile, in this way hornresp model is more accurate, the same as I did for altec816.
To use smaller driver you need to adjust dimensions accordingly, in your case you need reduce them, they don't need to keep the aspect ratio of the original design once you are going to use different driver, so tune the rear chamber the vent and the horn as you prefer.
It's not, you just double click dimensions and change the value, nothing special. The hard-work was already made so anyone with any knowledge are able to use them.
Let me know if it worked for you so I can publish or fix any issue you find. Attached there is also a hornresp input *.txt that you can use importing from hornresp to start playing around.
Attachments
How in the h3ll am I late to this party!?!?!?! This thread deserves a STICKY. Excellent work LORDSANSUI! Now to start playing with the software.
That is chineese crap using the famous brand. But fortunately the production of hifi drivers is continued by a former employee who bought manufacturing equipment 25 years ago and is now using the name Great Plains Audio https://great-plains-audio.myshopify.com/products/515-8c-15-low-frequency-alnico-loudspeaker
Unfortunately the price were greatly increased after a recent takeover, quality and specs same as Altec
The 515 is one of the best sounding woofers ever made
I'm happy you like it. I hope you can enjoy and it may became useful for you. It has the potential to make your sketches a lot faster.
Don't worry, there are some guys that we say they have two left hands or in a soccer context we say they have two left legs LOL.
This position was chosen just because I set up the sketch in the X-Y plane and when the mouth is in the right side, when you switch to 3D environment, activating the standard isometric view you can the see the mouth, if you swap the mouth position to left side, the isometric view will show you the back of the box.
Don't worry, there are some guys that we say they have two left hands or in a soccer context we say they have two left legs LOL.
This position was chosen just because I set up the sketch in the X-Y plane and when the mouth is in the right side, when you switch to 3D environment, activating the standard isometric view you can the see the mouth, if you swap the mouth position to left side, the isometric view will show you the back of the box.