60x40 - MEH - DE250 - 4NDF34 - 3D Printed project - Mid/Hi - 600hz to 20khz

[Psytron]

Hi
I have been out of the speaker building game for quite a while and wanted to spice up the top section on my MT122 (speakerplans.com). I have already been running them with an added DE250 but want to split up the 12' section into separate cabs and make a MEH with 2x 4NDF34 and 1x DE250 to go on top.

Previous DIY for me has mainly been bass subs(bandpass horns / tapped horns) and some bass reflex tops.

This will be a completely open sourced project where I share everything via Github

Currently I am getting (re)familiar with modelling software (Akabak and hornresp) and trying to get a smoothish workflow for prototyping, happy for suggestions and links to add to my collection.

Hopefully have some plots of the horn and CD soon.

 

[arcgotic]

Hello,
What are you loading the mid-bass section of MT122 with? Do you have a measurement please? Thanks!

 

[Psytron]

The P.Audio SN12b.
I don't have a measurement of mine however you can find one here (forum.speakerplans.com) made by Rog

 

[fluid]

I ran an ABEC sim of your configuration file as you seemed to be having trouble getting a result. This is what it looks like normalized to 10 degrees off axis.
Infinite baffle is not a bad way to start but it will look different in freespace.

 

[kipman725]

as the coverage angle is only 60x40 you might want to consider a larger throat compression driver if output is important and perhaps 4x 4NDF34. I think the maximum operating frequency of your mids will be about 1.5kHz from others results with this driver.

 

[Psytron]

I ran an ABEC sim of your configuration file as you seemed to be having trouble getting a result. This is what it looks like normalized to 10 degrees off axis.
Infinite baffle is not a bad way to start but it will look different in freespace.

View attachment 1177155

View attachment 1177156

Thanks fluid.
I am working out what I have to add to the Akabak mesh after importing as the imported project does not give me an output. I am finding the learning curve quite steep at the moment but that just makes it more of a challenge.
Currently working through it starting with getting ath 4.8.2 to talk to gmesh without getting "Unknown control point 1 in GEO curve 1" type issues. Most likely its my horn cfg

Fluid, can you quickly summarise which files you used and the process? Dot points is fine, I am just wondering if I have software config issues or its my horn description.. TIA

 

[Psytron]

as the coverage angle is only 60x40 you might want to consider a larger throat compression driver if output is important and perhaps 4x 4NDF34. I think the maximum operating frequency of your mids will be about 1.5kHz from others results with this driver.

You might be right, I currently plan to have a single 12, 2x 4 and 1x CD, if i can get the mids up to 1.5kHz I think I will call it a success, If I start going through diaphrams I will move up to a 2'CD.

 

[fluid]

Fluid, can you quickly summarise which files you used and the process? Dot points is fine, I am just wondering if I have software config issues or its my horn description.. TIA

I used your config file in ABEC straight from Ath. The observations are different between ABEC and Akabak so importing the ABEC project from Ath still needs some manual input. Marcel has a link to the ABEC installer on his website, my advice is to use ABEC with Ath generated projects unless you understand how to drive Akabak. Having said that it is not hard to create your own observation options in Akabak but it has to be done manually.

Trying to generate STL’s directly in the later versions of Ath doesn’t work, but they are not really much use and can be exported from ABEC if you really want one.

 

[Psytron]

I used your config file in ABEC straight from Ath. The observations are different between ABEC and Akabak so importing the ABEC project from Ath still needs some manual input. Marcel has a link to the ABEC installer on his website, my advice is to use ABEC with Ath generated projects unless you understand how to drive Akabak. Having said that it is not hard to create your own observation options in Akabak but it has to be done manually.

Thank you, I watched a video on YT that has allowed me to add the mesh and specify the domains etc and after enabling fixed driving I have some plots. I will have a look at ABEC and see if that makes life a little easier.

 

[kipman725]

You might be right, I currently plan to have a single 12, 2x 4 and 1x CD, if i can get the mids up to 1.5kHz I think I will call it a success, If I start going through diaphrams I will move up to a 2'CD.

ah ok this makes sense if your not trying to make something with monstrous output. I would guess 4*12" would be needed to match a 2" throat comp.... BMS do comps that are 1" throat and capable of 1kHz crossover.