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Doug's dual Gjallarhorn build

post #1 of 184
Thread Starter 
I figured I'd start a new thread instead of mooching off of the other threads with my questions... I have started my build for the two Gjallarhorns designed by Ricci - thanks for sharing the plans Josh! I'm building these for my 2700 cu ft living room that we use for watching movies, listening to music, entertaining, etc. Not really a "true" HT because it's the main room of our house and there are several different openings to the room, two windows, sliding glass door, vaulted ceiling, fireplace. The goal is to have this room +10 on WAF by looking like a "normal room," but with ninja-stealth, bone crushing sound coming from the shadows.

I chose the G-horn because it's output of sheer terror down to 15hz, which is as low as I care about, below 15hz doesn't do anything for me. I like to turn it up to 11, and have a history of destroying my drivers because of my generosity toward the volume knob, but also because this living room is difficult to pressurize. These will be placed in the attic, behind the vaulted ceiling and firing through to the room from the front and rear left side corners. As soon as these are finished and tested, demo on the room begins for our remodel, subs get hoisted up to the attic for placement.

So far I have the sheets of BB cut according to the plans and the horn-path drafted to the side panels. Tomorrow I will begin with attaching the first couple of panels with PL, also using the Kreg system and screws.





Here is the vaulted ceiling. After bracing and prepping the ceiling structure, the middle gets ripped out, subs go in, one goes to each corner.



Some other shots around the space. Layout will be the same after the remodel is complete





Edited by d_c - 10/20/13 at 3:17pm
post #2 of 184
Welcome to the club. When are the dual Othorns joining the party?
post #3 of 184
wow, that should be awesome! As an infinite baffle guy, I love the idea of making use of the extra space to bolster your rooms performance!

speaking of ib, why go ib instead of a horn? Horn has awesome output, takes less power but ib is easy to build and sounds amazing. I'm running 2- 18's and a crown xls 1500 and it feel like it'll rip the house off the foundation....
post #4 of 184
neat!

how do you intend to pick where to chop the hold in the ceiling?

also, might need to upgrade the mains...maybe. :-)

"speaking of ib, why go ib instead of a horn? Horn has awesome output"

you answered your own question. funny the way the brain works is what freud says. :-)
post #5 of 184
Thread Starter 
Quote:
Originally Posted by dsl1 View Post

Welcome to the club. When are the dual Othorns joining the party?

Thanks! Good to be here. Baby steps...

Quote:
Originally Posted by rr14 View Post

wow, that should be awesome! As an infinite baffle guy, I love the idea of making use of the extra space to bolster your rooms performance!

speaking of ib, why go ib instead of a horn? Horn has awesome output, takes less power but ib is easy to build and sounds amazing. I'm running 2- 18's and a crown xls 1500 and it feel like it'll rip the house off the foundation....

I love building horns, and love the sound. I'm sure IB is awesome, but I just chose a different path. It would take quite a few IB subs to match the output of these two, and that would not qualify as a +10 on the WAF (unless I built a couple of manifolds), but that is another discussion entirely. Someday I would like to include some IB subs somewhere. Lake house maybe? I need to get one first...
post #6 of 184
Thread Starter 
Here's the stack for one of the horns, minus the side pieces





I have 4 of these drawn out, then after re-reading Luke's build thread for the 20th time, I realized that I mis-measured the same corner by 1/4". Several of the numbers on the PDF were overlapped, so I misread the measurement. I think the rest are on target.

post #7 of 184
Quote:
Originally Posted by rr14 View Post

wow, that should be awesome! As an infinite baffle guy, I love the idea of making use of the extra space to bolster your rooms performance!

speaking of ib, why go ib instead of a horn? Horn has awesome output, takes less power but ib is easy to build and sounds amazing. I'm running 2- 18's and a crown xls 1500 and it feel like it'll rip the house off the foundation....

I remember thinking that about my DD-18...and then my single 5400...and then my dual 5400s...and then my quad 5400s... =)

The Ghorns give new meaning subwoofer violence...my concrete foundation hates me.
post #8 of 184
Quote:
Originally Posted by d_c View Post

Here's the stack for one of the horns, minus the side pieces





I have 4 of these drawn out, then after re-reading Luke's build thread for the 20th time, I realized that I mis-measured the same corner by 1/4". Several of the numbers on the PDF were overlapped, so I misread the measurement. I think the rest are on target.


There were a couple angles I had to re-draw quite a few times to get it right as well.

An easy way to tell if you have it right is that if you start at the beginning of the horn path, the beginning of the path will be smaller than the end of that path before the next turn, and the end of that path will be smaller than the beginning of the next path in the fold. If not, something's not right =)
post #9 of 184
Thread Starter 
Thanks Luke, I found that a good way to check my work as well. Ricci's plans mention starting at the baffle and working outwards, bracing as you go. I notice that you went the opposite way. Any reason or was that a change in the plans?
post #10 of 184
Awesome dude!

I am looking forward to your impressions when you fire those bad boys up!! cool.gif
post #11 of 184
I feel bad for the spine that carrys those boxes to the attic. subbed in for ultimate sub violence that achieves a PLUS10 WAF smile.gif
post #12 of 184
Thread Starter 
The first panel is already freaking heavy without anything glued to it! I envision putting my extension ladder to the attic with plywood strapped to it. 2x2 tracks for a furniture dolly screwed to the plywood. Horn strapped to the furniture dolly and hoisted up to the attic on the tracks with a wench or Z-rig, and 3 guys on each side guiding it, two in the attic to receive. I will have two 4x8 sheets of 15/16 decking down in the attic next to the vault to work on already for putting the bracing and sub mounts together. I always have lots of craft beer in the fridge, so people are always eager to help. This is going to be fun.
post #13 of 184
Quote:
Originally Posted by d_c View Post

The first panel is already freaking heavy without anything glued to it! I envision putting my extension ladder to the attic with plywood strapped to it. 2x2 tracks for a furniture dolly screwed to the plywood. Horn strapped to the furniture dolly and hoisted up to the attic on the tracks with a wench or Z-rig, and 3 guys on each side guiding it, two in the attic to receive. I will have two 4x8 sheets of 15/16 decking down in the attic next to the vault to work on already for putting the bracing and sub mounts together. I always have lots of craft beer in the fridge, so people are always eager to help. This is going to be fun.

We changed the venue for our GTG in August just so we didn't have to move the Ghorns up the stairs...I don't envy this task of yours at all. I'm guessing the cabinet without the 80lb driver weighs around ~300lb's...
post #14 of 184
the password is moving/lifting straps. :-)
post #15 of 184
Quote:
Originally Posted by LTD02 View Post

the password is moving/lifting straps. :-)

Uhhh...these are 45" long and 45" tall...so for us it was more that we would have had to remove the metal railing on top the stairs in order to make the turn out the door =)
post #16 of 184
Thread Starter 
Oh boy... 1st panel (G) for the baffle (32 7/8") is 5/8 too long and I don't see the angled piece anywhere in the plans - Are my measurements correct on the side panel?

Shows how far over the baffle piece is compared to my panel mark (10 5/16" from the edge)




do I cut this angle piece from scrap? Is 2.5 the correct distance from the edge?

Edited by d_c - 10/21/13 at 9:24am
post #17 of 184
Doug, you did see this pic I uploaded, correct?

Capture_zps0f74ba46.jpg

Hope it helps!
post #18 of 184
Quote:
Originally Posted by d_c View Post

Oh boy... 1st panel (G) for the baffle (32 7/8") is 5/8 too long and I don't see the angled piece anywhere in the plans - Are my measurements correct on the side panel?


Shows how far over the baffle piece is compared to my panel mark (10 5/16" from the edge)




do I cut this angle piece from scrap?

I didn't put an angle on the driver panel. I just made two sharp angles on the 1/2" piece that connect the driver panel with the front panel.
post #19 of 184
Thread Starter 
OK, I just matched my panels with your inch fractions on the Side Panel PDF in your build thread, and they are the same. I will proceed with matching my cuts to that vs. the actual measurements listed on the cut sheet, and do what you did there with the angled piece on the mouth. The 45 in the plans is too sharp for that piece. Thanks again! Back to the table saw.
post #20 of 184
Quote:
Originally Posted by d_c View Post

OK, I just matched my panels with your inch fractions on the Side Panel PDF in your build thread, and they are the same. I will proceed with matching my cuts to that vs. the actual measurements listed on the cut sheet, and do what you did there with the angled piece on the mouth. The 45 in the plans is too sharp for that piece. Thanks again! Back to the table saw.

Yeah, once I drew the template, I made all my cuts from measuring from the drawn template instead of the PDF.
post #21 of 184
Good luck Doug...I dont want to discourage you but I wish I would have given you the new fold as it is much cleaner and less cutting. I don't think I had it done at the time though. The ones you are working off of are accurate because it all fits together in Solidworks but as Luke says you can't really worry about getting it down to the last decimal place. Just make sure it is close and it'll be fine.
post #22 of 184
Nice!! cool.gif

Subscribed.
post #23 of 184
Thread Starter 
Quote:
Originally Posted by Ricci View Post

Good luck Doug...I dont want to discourage you but I wish I would have given you the new fold as it is much cleaner and less cutting. I don't think I had it done at the time though. The ones you are working off of are accurate because it all fits together in Solidworks but as Luke says you can't really worry about getting it down to the last decimal place. Just make sure it is close and it'll be fine.

Oh! If there is an improvement in performance, I will change direction. If only less cuts, I will plant more trees and continue. I'm full speed ahead otherwise. Let me know Josh, I can redraw the panels tomorrow if I need to, if it is better.
Edited by d_c - 10/21/13 at 6:45pm
post #24 of 184
Just go ahead as planned since I don't have the prints done.
post #25 of 184
Thread Starter 
A little more progress today on the first two panels. Cut the hole for the drivers - could have been 1/8-1/4" tighter, but it'll work. TC Sounds recommended cutout is a little too big for a front mount driver.

IMG_20481_zpsb3a9d099.jpg










I used this 1/8" roundover to help protect the surround when I mount the driver to the baffle later.






I pulled the glass out of our living room table so I could center the driver for marking the holes.


Edited by d_c - 10/31/13 at 8:16am
post #26 of 184
Quote:
Originally Posted by d_c View Post

A little more progress today on the first two panels. Cut the hole for the drivers - could have been 1/8-1/4" tighter, but it'll work. TC Sounds recommended cutout is a little too big for a front mount driver.






I used this 1/8" roundover to help protect the surround when I mount the driver to the baffle later.






I pulled the glass out of our living room table so I could center the driver for marking the holes.


Dang those magnets are huge...

I think it's awesome that 4 of the 5 LMS 5400s I've ever purchased will be used in Ghorns. Heck yeah
post #27 of 184
Thread Starter 
I use a punch to mark the holes for the 10/24 1.5" bolts and t-nuts. I use a 3/4 paddle bit to start the hole, but it makes it convex. Then I make a pilot hole for the bolt with 1/8" bit.





Then I use the 3/4" forstner bit to make the hole nice and flat to seat the t-nut. I don't have a drill-press, so the paddle bit happens first so the forster bit doesn't move on me. I enlarge the hole again with a 1/4" bit for the t-nut.





One too many beers and I started cutting holes for the t-nuts on the wrong side. Filled it in with some Bondo. derpy-derp






T-nuts with Gorilla Glue applied to the prong side and pulled tight with a washer on the driver side


Edited by d_c - 10/23/13 at 11:57am
post #28 of 184
Thread Starter 
I did see the PDF above Luke, thanks for posting it! I love these drivers and they are crazy heavy. We watched Ironman III the other night and realized that two are almost enough, almost. Just kidding, it's never enough!


The Kreg jig is awesome. Get one if you don't have one and you like building speakers.





I'm tacking in the rest of the panels with a brad nailer to hold them in place while I screw in the panels. These first ones turned out OK, but PL gets pretty smeary and the panels move about 1/16" when the Kreg screws are tightened in. I like it to be perfect, so smears just won't do.





IMG_20551_zps40c2f9f3.jpg
Edited by d_c - 10/31/13 at 8:17am
post #29 of 184
Thread Starter 
The T-nuts hung over the edge so I adjusted those with the angle grinder and abrasive wheel. There was still plenty of room for all 3 prongs to contact the baffle. My mess on the panel at the top show my confusion of where the mark was supposed to go, but Ricci and Luke helped me figure it out.









The first few braces were tricky, but I measure 50x and cut once, so they were a perfect fit. I made a spacer to hold the braces to the correct height which saves quite a bit of time not having to measure each one. There are a LOT of braces in these things!

post #30 of 184
Thread Starter 
Fast forward a week. This is the progress I made in a 9 hour day yesterday.


IMG_4213_zpsbc15ab30.jpg



IMG_4215_zps5e6e9f43.jpg



IMG_4216_zpsa0a8969d.jpg



IMG_4218_zps7b156e74.jpg
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