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Dual GJALLARHORNs!

60K views 795 replies 79 participants last post by  lukeamdman 
#1 ·
A trip over to RMK’s place a couple days ago got the wheels turning. Long story short, two JTR Orbit Shifters, which combined is two 18” drivers and 8kw of power, gave my quad 18’s and 16kw of power a run for their money! To be more specific, I feel his setup had greater output above 30hz, and mine had greater output from the mid 20’s on down.


The efficiency of the horn design definitely impressed me, so I started to look around. It didn’t take me long to find the GJALLARGORN on Ricci’s data-bass.com. From his measurements, just one gjallarhorn will outperform all four of my sealed 5400s from 16-40hz-ish, and obviously with far less power.


The plan is two build two of these, and re-use two of the 5400s from one of my sealed cabinets. That means I’ll still have two other sealed 5400s powered by a LG clone, which can help cover the top 60-80hz portion where the gjallarhorn may need some help. The only investment for me is the cost of the wood.


Ricci already emailed me the detailed plans, so all I have to do is find 4x8 sheets of quality Baltic birch and I’ll get started:)



UPDATE:



















































http://s1121.photobucket.com/user/lukeamdman/media/Misc/20130826_172928_zps7a75d8b9.jpg.html
 
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#227 ·
Sorry...there are probably a few errors in there. I probably put too much detail in. I am currently trying to update the plans for both the Othorn and the GH. Cleaning things up and making a few improvements...just take your time and double check me. Once you get the layout on a side panel the rest should really just be a matter of common sense building and looking at the basic panel placement.
 
#228 ·

Quote:
Originally Posted by Ricci  /t/1443947/dual-gjallarhorns/210#post_22967121


Sorry...there are probably a few errors in there. I probably put too much detail in. I am currently trying to update the plans for both the Othorn and the GH. Cleaning things up and making a few improvements...just take your time and double check me. Once you get the layout on a side panel the rest should really just be a matter of common sense building and looking at the basic panel placement.

No problem Josh!

We appreciate all you do!
 
#229 ·

Quote:
Originally Posted by Ricci  /t/1443947/dual-gjallarhorns/210#post_22967121


Sorry...there are probably a few errors in there. I probably put too much detail in. I am currently trying to update the plans for both the Othorn and the GH. Cleaning things up and making a few improvements...just take your time and double check me. Once you get the layout on a side panel the rest should really just be a matter of common sense building and looking at the basic panel placement.

Yes, apologize immediately for doing all the work in making these awesome subwoofer designs and testing them. lol
 
#230 ·

Quote:
Originally Posted by lukeamdman  /t/1443947/dual-gjallarhorns/210#post_22968396


Yes, apologize immediately for doing all the work in making these awesome subwoofer designs and testing them. lol

Or that!
:D
 
#233 ·
It would a bonus if there were a tall/narrow version of this design, ala THT LP style.


Anyone interested in tackling it?


I would gladly do it if I had even 2% of the know how.
 
#234 ·
So It looks like I'm out of luck, I cannot find anyone to build this beast, I've been turned down now by 23 different shops and custom furniture makers lol Every single response has been the same. "The plans are to complicated and they have no idea how to put it all together with the plans provided" They all were saying about having to do the conversions for the butt joints and so on.


lukeamdman how did you do the conversion to make all the pieces fit for butt joints on the cut lists? it looks like you'd have to convert all the measurements to make it work? I'd have no idea where to start.


The last guy I'm talkign to seem willing to give it a try but says he needs useable shop drawings with panels labeled and useable measurements to even consider building one lol
 
#235 ·

Quote:
Originally Posted by N8DOGG  /t/1443947/dual-gjallarhorns/210#post_22973413


So It looks like I'm out of luck, I cannot find anyone to build this beast, I've been turned down now by 23 different shops and custom furniture makers lol Every single response has been the same. "The plans are to complicated and they have no idea how to put it all together with the plans provided" They all were saying about having to do the conversions for the butt joints and so on.


lukeamdman how did you do the conversion to make all the pieces fit for butt joints on the cut lists? it looks like you'd have to convert all the measurements to make it work? I'd have no idea where to start.


The last guy I'm talkign to seem willing to give it a try but says he needs useable shop drawings with panels labeled and useable measurements to even consider building one lol

I'm not using the cut list. From page 5 on the PDF I converted each measurement to the nearest 32nd of an inch. I then drew the template onto the side panels as seen in the previous pictures.


From the drawn template I can measure the angles of each cut. Basically, I'm making these one piece at time.


Honestly, it's not going to be that bad. I'll post pictures step by step in case anyone is curious.


This would have been overwhelming if it were my first DIY project for sure.
 
#237 ·
Ricci, does this picture show all the cross-bracing they used, or did add more later like the pdf shows?




Here's the PDF:




Thanks!
 
#239 ·
It is really not as hard as it seems at all. You have to remember I originally tried to make this a kit to be cut on a cnc and then lock together perfectly. Luke has it right... Forget all of that to the umptenth precision on the measurements and the dado's etc...It is really not that hard...I'm not surprised most cab shops won't touch it though, too much work on something they are unfamiliar with. I mean every panel has exactly what it should be and it is not that hard to put together. It is just not worth it for them to fool with it when they can just build another kitchen cabinet or table.


1. You cut the 2 side panels and mark out the path on one. (This is the hard part.) Everything else stems from there and is built upon that panel.

2. Every internal piece from there except for bracing will have the same 22.5"-22.6" width. (exactly what is not important so long as they are the same. )

3. Cut the length of each panel followed by the angles on the ends of the panels somewhat close then just make sure they are centered on the path layout and glue and screw the **** out of them. (if you are 1/4" off on your length of the bend panels it won't amount to anything acoustically. Don't worry about perfection.

4. Use butt joints for everything if you want.

5. Start from the driver baffle and internal bend panels and work your way out. Add bracing as you go. It is bracing it doesn't have to be perfect. It is bracing. PL the hell out of it and screw em in if possible. Get crazy put extra in...Whatever just don't block the air flow. The edge of every brace should always be in the path not the side.

6. Continue with the rest of it.


The hardest part will probably be the driver access panel but it is not that difficult with a decent router and jig. It doesn't have to be exactly that size just get it where your driver fits in. Hell you can just jigsaw cut a big hole and scab a whole other piece of material over the hole if you want.


Again this is being way over thought. The critical component is getting the horn path correct. I can't stress that enough. That is the main key thing. After that it should be easy to go piece by piece. The rest is just building it solid, sealed up and well braced.


Luke,

Yes more bracing was added towards the end. Actually I am revamping the design a bit and simplifying it a bit and adding even more bracing. Instead of a center brace internally I am using 2 equally spaced braces on each internal panel. All except for at the mouth area.
 
#240 ·

Quote:
Originally Posted by Ricci  /t/1443947/dual-gjallarhorns/210#post_22974908


It is really not as hard as it seems at all. You have to remember I originally tried to make this a kit to be cut on a cnc and then lock together perfectly. Luke has it right... Forget all of that to the umptenth precision on the measurements and the dado's etc...It is really not that hard...I'm not surprised most cab shops won't touch it though, too much work on something they are unfamiliar with. I mean every panel has exactly what it should be and it is not that hard to put together. It is just not worth it for them to fool with it when they can just build another kitchen cabinet or table.


1. You cut the 2 side panels and mark out the path on one. (This is the hard part.) Everything else stems from there and is built upon that panel.

2. Every internal piece from there except for bracing will have the same 22.5"-22.6" width. (exactly what is not important so long as they are the same. )

3. Cut the length of each panel followed by the angles on the ends of the panels somewhat close then just make sure they are centered on the path layout and glue and screw the **** out of them. (if you are 1/4" off on your length of the bend panels it won't amount to anything acoustically. Don't worry about perfection.

4. Use butt joints for everything if you want.

5. Start from the driver baffle and internal bend panels and work your way out. Add bracing as you go. It is bracing it doesn't have to be perfect. It is bracing. PL the hell out of it and screw em in if possible. Get crazy put extra in...Whatever just don't block the air flow. The edge of every brace should always be in the path not the side.

6. Continue with the rest of it.


The hardest part will probably be the driver access panel but it is not that difficult with a decent router and jig. It doesn't have to be exactly that size just get it where your driver fits in. Hell you can just jigsaw cut a big hole and scab a whole other piece of material over the hole if you want.


Again this is being way over thought. The critical component is getting the horn path correct. I can't stress that enough. That is the main key thing. After that it should be easy to go piece by piece. The rest is just building it solid, sealed up and well braced.


Luke,

Yes more bracing was added towards the end. Actually I am revamping the design a bit and simplifying it a bit and adding even more bracing. Instead of a center brace internally I am using 2 equally spaced braces on each internal panel. All except for at the mouth area.

If you think more bracing is needed, and you did imply more was needed before, I'll incorporate your idea and have two braces parallel to each other evenly spaced.


One last question. Any gasket tape needed between the driver and the plate? I see you left that black rubber surround thingy on the 5400 when you bolted it in.
 
#241 ·

Quote:
Originally Posted by Ricci  /t/1443947/dual-gjallarhorns/210#post_22974908


It is really not as hard as it seems at all. You have to remember I originally tried to make this a kit to be cut on a cnc and then lock together perfectly. Luke has it right... Forget all of that to the umptenth precision on the measurements and the dado's etc...It is really not that hard...I'm not surprised most cab shops won't touch it though, too much work on something they are unfamiliar with. I mean every panel has exactly what it should be and it is not that hard to put together. It is just not worth it for them to fool with it when they can just build another kitchen cabinet or table.


1. You cut the 2 side panels and mark out the path on one. (This is the hard part.) Everything else stems from there and is built upon that panel.

2. Every internal piece from there except for bracing will have the same 22.5"-22.6" width. (exactly what is not important so long as they are the same. )

3. Cut the length of each panel followed by the angles on the ends of the panels somewhat close then just make sure they are centered on the path layout and glue and screw the **** out of them. (if you are 1/4" off on your length of the bend panels it won't amount to anything acoustically. Don't worry about perfection.

4. Use butt joints for everything if you want.

5. Start from the driver baffle and internal bend panels and work your way out. Add bracing as you go. It is bracing it doesn't have to be perfect. It is bracing. PL the hell out of it and screw em in if possible. Get crazy put extra in...Whatever just don't block the air flow. The edge of every brace should always be in the path not the side.

6. Continue with the rest of it.


The hardest part will probably be the driver access panel but it is not that difficult with a decent router and jig. It doesn't have to be exactly that size just get it where your driver fits in. Hell you can just jigsaw cut a big hole and scab a whole other piece of material over the hole if you want.


Again this is being way over thought. The critical component is getting the horn path correct. I can't stress that enough. That is the main key thing. After that it should be easy to go piece by piece. The rest is just building it solid, sealed up and well braced.


Luke,

Yes more bracing was added towards the end. Actually I am revamping the design a bit and simplifying it a bit and adding even more bracing. Instead of a center brace internally I am using 2 equally spaced braces on each internal panel. All except for at the mouth area.

i dunno, I think the same thing as you but apparently they don't lol. I think they are worried that there is no "where to place every panel" type instructions and maybe are worried about putting something where it doesn't belong. When Luke posts up more info, maybe I can take it back to the willing guy I have. I'm assuming the CNC plans are what is scaring them.
 
#242 ·
Luke the rubber ring should be fine.


I will send you updated plans as soon as I can just so you can see what I did with the bracing. You can use that or some of it or whatever. I'm just going for overkill on it. Unfortunately I am out of country for a few weeks and won't be able to get you that for awhile. I don't have that stuff on my laptop. Basically I doubled up the bracing we already talked about to split the path into thirds instead of halves. I made the mouth brace a little longer to get more of the bottom panel, I added another set of braces right by the driver in the throat by the first turn. I also beefed up the triangle shaped corner panel into 2 identical pieces that connect into the driver baffle and contact the bottom panel a little more.
 
#247 ·

Quote:
Originally Posted by jpmst3  /t/1443947/dual-gjallarhorns/240#post_22981114


Would there be an advantage to adding foam to the inside corners or each fold?


I see some designs with it added and others without it....

Each time I've tried it, it has not helped where I wanted it to. In some cases, it actually cost me SPL.


I don't add damping material inside my horns any more.
 
#248 ·

Quote:
Originally Posted by lilmike  /t/1443947/dual-gjallarhorns/240#post_22983146


Each time I've tried it, it has not helped where I wanted it to. In some cases, it actually cost me SPL.


I don't add damping material inside my horns any more.

Interesting.


Thanks for the reply!
 
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