K-402 horn - worth the effort to DIY?

BlueVUMeters

BlueVUMeters

Active Member
I've been considering building some K-402 clones or something similar. I would be pairing them with my peavey FH-1 clones and running a 2-way setup probably with a sub to fill out the bottom end. Does anyone have detailed measurements or drawings of the horn construction? I'm fairly happy with my current 3-way setup but just feel like experimenting a bit. I have the tools to 3d print them in sections but probably more practical to just construct them out of Baltic birch and solid maple/birch for the curved sections. I'm also open to other similar designs if there's a better option out there?
 
Register to hide this ad
Using different materials/densities, I'd be concerned about picking up unexpected resonances, but it's an interesting idea . . .
 
Some where I have files I found online from someone who had meh 402's cut from mdf and assembled. If you look around there out there.
 
tadawson said:
Using different materials/densities, I'd be concerned about picking up unexpected resonances, but it's an interesting idea . . .
Click to expand...
I don't think that is an issue. The latest iteration of the 402 from Klipsch is very thin in my opinion. There were three versions of these I know of. The first one was some sort of hard brittle plastic and if you dropped them they would shatter. The second version was decent flexible plastic and about a 1/4" thick. The third version was much thinner then version two. All three however sound good and do what only the 402 horns will do. Count yourself really lucky if you ever run across a used set.

I don't know what a new set would cost but I would probably go this route for a personal set of speakers. What you get with that are drivers designed to work with that horn. The 1132 driver now comes with a tractrix printed internal phase plug and I have had the printed and the cast phase plug models. There is a clear improvement with the tractrix and you will only get that from Klipsch. There is also a secondary phase plug that goes in between the driver and the horn and these should be stock with the new set. I have a set of these on my Super MWM's and they are outstanding.
 
Last edited:
But none of that addresses whether there will be resonances in a 3d printed horn. It's quite possible that the density/thickness/etc. on the two factory versions were tested and designed to avoid them. We just don't know, but it certainly would be ugly of a horn had a structural resonance in it's working frequency range. Coult it be addressed? Likely . . . just don't assume that just because someone released a set of STLs that that has been considered . . .
 
Last edited:
that file is designed to have the void filled with gypsum so it should be about twice as dense as solid ABS. and if you didnt want to do infill and print them the solid then it should be about the same. filaments with glass or carbon fibers would be stiffer and the same density. so i don't see any reason the resonances would be higher in frequency than originals due to the material given the same thicknesses.
 
TheAbide said:
that file is designed to have the void filled with gypsum so it should be about twice as dense as solid ABS. and if you didnt want to do infill and print them the solid then it should be about the same. filaments with glass or carbon fibers would be stiffer and the same density. so i don't see any reason the resonances would be higher in frequency than originals due to the material given the same thicknesses.
Click to expand...
You assume that everyone will use the specified material, and not just what they have . . .

I admit, I didn't look that deep. Sounds like it was (somewhat atypically these days) though of.
 
Yeah. I'd assume anyone with a printer that has a 400mm bed and the capability to finish that whole thing will indeed. It's not just going to be a spool of whatever. Thats going to take multiple kg of filament that anyone I know that prints would be making an order for and not just using whatever is on the shelf because it's going to end up being all sorts of colors if they did. I found a guy on FB that 3d scanned one though and I'm trying to contact him about it.
 
Hmmm. . . . I had thought that I had seen a note that they had files to print it is smaller sections for those who did not . . . that's what triggered my comment . . . that doesn't sound like a terribly solid part done that way.
 
It is. Those "small" sections are still larger than your average printer. Your average printer has a 255mm print bed Most larger ones are moving to a 350mm these days. This is designed for a 400mm. So while it's smaller chunks it still requires a relatively large printer which isn't that common(not necessarily more expensive than a smaller printer though). The assembled pieces are not an issue either. Using abs you can just weld with acetone or use epoxy for just about anything. You'd probably want to use some sort of filler to smooth and hide the seams then paint them at the end though.
If you know what you're doing you could probably buy a kobra max, filament, and other materials and still make 2 for less than buying real k402s as long as you toss your own labor value out the window.
 
TheAbide said:
It is. Those "small" sections are still larger than your average printer. Your average printer has a 255mm print bed Most larger ones are moving to a 350mm these days. This is designed for a 400mm. So while it's smaller chunks it still requires a relatively large printer which isn't that common(not necessarily more expensive than a smaller printer though). The assembled pieces are not an issue either. Using abs you can just weld with acetone or use epoxy for just about anything. You'd probably want to use some sort of filler to smooth and hide the seams then paint them at the end though.
If you know what you're doing you could probably buy a kobra max, filament, and other materials and still make 2 for less than buying real k402s as long as you toss your own labor value out the window.
Click to expand...
The cost of hiring someone to do this or funding equipment and supplies to do this would be far greater then just buying a new set where your labor is opening the box. Plus you have a serial number they will honor for replacement parts. I bought a set of 402 horns years ago from JWC next to Atlanta. He sold them to me for $220 each which was the Klipsch cost for just the horns about eight years ago. He had a serial number to get them though. Somehow people get this idea these printers are magic and can do anything but have never actually used them. I have been a machinist and CAD designer since 2003 and I get a big chuckle over conversations like this one. Now if I were to do this I would get a laser scan. Probably $500 or so. I have software that can take scan data and make a solid model to work off of. No software you have to hire the scanner dude to do that too if he can and there goes another $500 I would imagine. From that I could take the horn solid and do a boolean remove and have an exact solid of the inside of the horn I could then machine a solid wood model from. This then could be used to create fiberglass horns from and be reusable for more then one. If you could find someone willing to let you use their horn to make a cement form from I suppose you might do that. I know you won't get my horn to do that with though.

I have given this topic thought over time. If I were serious about doing this I would get a good cad model and break it down into four sections. Left and right, top and bottom. I would go to a sheet metal shop that could cut the blanks needed and have them form these up on a cnc Press Brake. I think they could get real close and then I would bring them back to my shop and weld them up. But then you see I own the $12,000 software package you need to do this with and none of you do. And I have decades of TIG welding experience too.

Anyway it is great fun to pass the time of day coming up with all this and I enjoy reading it.
 
I print a lot for fun and make parts for people. They aren't magic but I do use one all the time. I'd totally agree if you could find a set that cheap. I'm talking about vs the cost of buying new from Klipsch which would definitely be cheaper for me to make than buy 3. I have plenty of experience on a haas, fusion, and tigging as well. I also have solidworks for hobbyists and access to full versions as well as access to a cnc router and laser table. I worked for the guy that bought some chorus parts from you years ago to make his own. My thought is to actually modify a scan model to already include the mounts and throats for 15s to make a MEH. Fiberglass molds would definitely be the cheapest way to replicate them but I just hate dealing with the stuff.
If you can still buy just the horns for under 1k a piece that's still the best route I just don't see that happening unless you get really lucky and I would need 3 for my uses. I have no desire to use the celestion axi in it and would rather go with a b&c dcx. Last I heard they weren't selling them without drivers unfortunately.
The laser scanner is where I think people get the wrong idea. Unless you have a high dollar one they are not as capable as their marketing would imply. The ones I've used were in the 1-2k price range and are great for small parts but don't work as well on large scans as you'd expect, and you better have a solid PC with tons of ram(which is getting prohibitively expensive by the day thanks to AI) to run it.
But they have also already been scanned. I did get a message back from someone who has but not sure if he's interested in sharing or selling it yet. Will keep you guys updated if it's something he wants to make available.
 
It seems more feasible to build out of wood in my opinion. I found some STL files for the MEH version posted on another forum. Everything is in Russian so it's a little hard to follow, but the dimensions seem fairly accurate. I'm thinking the flat sections could be made with 3/4 baltic birch, and then I'd have to make some large pieces of molding out of solid maple for the flare. The curved section looks to be around 6" wide, so these might need to be done in 2 sections on a shaper.

meh-1.png


meh-2.png
 
TheAbide said:
Yeah. I'd assume anyone with a printer that has a 400mm bed and the capability to finish that whole thing will indeed. It's not just going to be a spool of whatever. Thats going to take multiple kg of filament that anyone I know that prints would be making an order for and not just using whatever is on the shelf because it's going to end up being all sorts of colors if they did. I found a guy on FB that 3d scanned one though and I'm trying to contact him about it.
Click to expand...

Me, not knowing much about how the 3d printing works, am presuming you to be saying "you better have enough when you start or you will be using whatever you have on hand AND, the colors might be different"

Though you say 'spool' and I have no idea what that is. I'm thinking of the liquid that gets lasered to solidify. If that's the case then maybe putting a bunch of different colors in at the start, might make it a psychodelic looking horn with all the colors interwoven.

I might be totally misunderstanding but I thought that might also be cool if that were the case.
 
TheAbide said:
I print a lot for fun and make parts for people. They aren't magic but I do use one all the time. I'd totally agree if you could find a set that cheap. I'm talking about vs the cost of buying new from Klipsch which would definitely be cheaper for me to make than buy 3. I have plenty of experience on a haas, fusion, and tigging as well. I also have solidworks for hobbyists and access to full versions as well as access to a cnc router and laser table. I worked for the guy that bought some chorus parts from you years ago to make his own. My thought is to actually modify a scan model to already include the mounts and throats for 15s to make a MEH. Fiberglass molds would definitely be the cheapest way to replicate them but I just hate dealing with the stuff.
If you can still buy just the horns for under 1k a piece that's still the best route I just don't see that happening unless you get really lucky and I would need 3 for my uses. I have no desire to use the celestion axi in it and would rather go with a b&c dcx. Last I heard they weren't selling them without drivers unfortunately.
The laser scanner is where I think people get the wrong idea. Unless you have a high dollar one they are not as capable as their marketing would imply. The ones I've used were in the 1-2k price range and are great for small parts but don't work as well on large scans as you'd expect, and you better have a solid PC with tons of ram(which is getting prohibitively expensive by the day thanks to AI) to run it.
But they have also already been scanned. I did get a message back from someone who has but not sure if he's interested in sharing or selling it yet. Will keep you guys updated if it's something he wants to make available.
Click to expand...
You are a rare animal with access to all that stuff as you know. It would be an enormous point cloud for the scan. I have wondered how the new camera like scanners would work?
The KPT-942/4 current production has the 402 horn with the 1132 driver. You do not have to get the Celestion.
Have you tried the B&C DCX? I got a set of those along with B&C's big horn and crossovers and they sounded like a PA system to me.
 
You must log in or register to reply here.
Back
Top Bottom