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Discussion Starter #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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Hey Luke,


You can use 5x5 panels too. You may have to change some of the cut sheet layouts but that is sort of what I meant in my last email. If you have questions let me know. i have lots of pictures and cad files.
 

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Awesome idea, tuned in. It is intriguing for sure.


On the face of it, more output is the allure, I get it. Josh's build is epic, period. However, fewer, higher output sources, vs. higher numbers of lesser output sources, doesn't always end up being advantageous when the acoustics of small rooms are involved.


But hell, I'd build it too! Especially having the benefit of the previous build, Josh's knowledge and hindsight.


Have fun and best of luck, this will be one to watch.
 

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That's gonna be potent set up! It'll be interesting to see if the 2 sealed will be enough to keep up in the 60 - 80 range.
 

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Discussion Starter #8
I think I already know the answer, but I thought I'd throw it out there anyway.


For a 4x8 sheet of this "Arauco" plywood at Menards, it's $40.




Or, I found a supplier that has 5x5 sheets of 13-ply, void free, baltic birch for about $72. Top quality stuff that I've used before.


That Arauco any good, or "you get what you pay for" and I should use BB?
 

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Actually his 4 LMS sealed drivers will do about 107 dBs and dual GH's will do 96 dBs.
 

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Discussion Starter #14

Quote:
Originally Posted by MKtheater  /t/1443947/dual-gjallarhorns#post_22675936


Actually his 4 LMS sealed drivers will do about 107 dBs and dual GH's will do 96 dBs.

You referring to 10hz?
 

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Quote:
Originally Posted by Decadent_Spectre  /t/1443947/dual-gjallarhorns#post_22675810


The GH is a DIY design by Ricci.

Thanks, didn't realize that, amazing. I'm catching up.



This is going to be an awesome build, lukeamdman.
 

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Quote:
Originally Posted by lukeamdman  /t/1443947/dual-gjallarhorns#post_22676091


You referring to 10hz?

Yes, at 10hz, sorry, I was on my phone which seems to auto correct to the wrong text. Quad sealed LMS 5400's will get you 120 dBs at 20hz and the GH will get you 128 dBs. So we have the sealed system doing 120 hz and 107 dBs where the GH will be doing 128 and 96. I don't know but the sealed system will be much flatter lower and still have enough output for any movie. I can tell you I had dual DTS-10's which had 122 at 20hz and 96 at 10hz and now my system has 107 dBs at 10hz and 123 dBs at 20hz. The sealed system absolutely rocks my theater and I ran sine wave testing higher than ever before. Having increased 16-80hz does nothing when you already have 130 dBs capable with the sealed system. You should have run those OS on scenes with known ULF only and then compared the two as you would have had at least 9 dBs more capable output at 10hz. Systems do wow you when they have lots of 20hz and up but imagine having the whole bandwidth at the same levels.
 

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Quote:
Originally Posted by MKtheater  /t/1443947/dual-gjallarhorns#post_22676598


Yes, at 10hz, sorry, I was on my phone which seems to auto correct to the wrong text. Quad sealed LMS 5400's will get you 120 dBs at 20hz and the GH will get you 128 dBs. So we have the sealed system doing 120 hz and 107 dBs where the GH will be doing 128 and 96. I don't know but the sealed system will be much flatter lower and still have enough output for any movie. I can tell you I had dual DTS-10's which had 122 at 20hz and 96 at 10hz and now my system has 107 dBs at 10hz and 123 dBs at 20hz. The sealed system absolutely rocks my theater and I ran sine wave testing higher than ever before. Having increased 16-80hz does nothing when you already have 130 dBs capable with the sealed system. You should have run those OS on scenes with known ULF only and then compared the two as you would have had at least 9 dBs more capable output at 10hz. Systems do wow you when they have lots of 20hz and up but imagine having the whole bandwidth at the same levels.

Actually I already went over all of this with Luke. He has 4 sealed LMS already which technically should be enough for anything sane. He knows what he is doing and doesn't really care a whole lot about
 

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Hey I am all for giant horns if one wants or needs to use less power, less subs, and 12hz is the bottom. It will be very impressive nonetheless.
 

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Siiiiick...


Ricci, this thing is an animal. Truly impressive. Will the dual sealed keep up in the upper bass and would the two extra lms's be better as two single sealed co-located? I suppose measurement would better dictate that...
 
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