2 x 36" THT LP with front firing mouth

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zpro
Posts: 49
Joined: Tue Jun 14, 2016 6:23 am
Location: Québec, Canada

2 x 36" THT LP with front firing mouth

#1 Post by zpro »

Hello,

So as promised I will be documenting my entire build in this thread! I am building them one at a time, so I only have the wood for one right now, although I do have both drivers.

Thanks to the help from a few members, I was able to narrow my choice down to two 36" THT LP that I will be using in the standing position with the new design that features a front firing mouth.

First of all, I have tried to upload my cultist but upload file formats seem to be acceptable...

I am planning to follow the guide as closely as I possibly can.

The wood I am using is fantastic quality Russian Baltic Birch, imported from Russia :D, with 9 plies equal thickness in the 1/2" and 13 plies in the 3/4". I am also using the specified PL polyurethane glue.

Yesterday I managed to build the jig for my table saw and was able to get my table saw blade square to the slider-slots that run parallel to it.

First question: Why in the world is the jig for my table saw not sliding well towards the end? It almost feels dangerous to use because as I aproach the end of the movement it begins gripping against the table enough that the entire table moves... :wall:

I also managed to cut the two sides to exactly 18" x 71 1/2" and draw out all the joints on it following the sketch up model for the joints that differed from the plan due to my choice of going with the front firing mouth variant.

I am planning on using drywall screws and the 90 degree jigs mentioned in the plan.

I would definitely appreciate any kind of feedback on how I am doing thus far.

Here are some photos to keep you all entertained! I am really happy to finally be starting this project :hyper: :

(You also get to see my hairy legs in the last photo! :clap: )

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Tom Smit
Posts: 7457
Joined: Sat Jan 05, 2008 1:24 pm
Location: Sarnia, Ont. Canada

Re: 2 x 36" THT LP with front firing mouth

#2 Post by Tom Smit »

First question: Why in the world is the jig for my table saw not sliding well towards the end? It almost feels dangerous to use because as I aproach the end of the movement it begins gripping against the table enough that the entire table moves... :wall:
Do you see any shiny spots on the sides of the runners that go in the mitre slots? If you do, take some sandpaper to them to thin the runner since that is where the runner is binding. Go carefully. Consider which way the sled may angle in reference to the blade, when you do this, to make sure that the blade stays within the kerf of the sled.
You might want to consider putting a fence on the other end of you sled for added stability/durability.
TomS

zpro
Posts: 49
Joined: Tue Jun 14, 2016 6:23 am
Location: Québec, Canada

Re: 2 x 36" THT LP with front firing mouth

#3 Post by zpro »

Thanks for the jig tips, I will check it out, although I think it is already ruined because the kerf is very wide due to the jig wobbling while i pushed it.

Parts 1 and 2 are glued! Perfect 90 degrees for part 1 and the side, I used screws. 7 degree bevel went very well with my old rickety table saw and I had to add an underside piece of plywood to which I fastened the entire build in order to add a small 90 degree piece on one end. This is because the front facing mouth variation does not go from end to end of the sides. I now am realizing that this glue makes the entire project quite very forgiving, it inflates like a balloon!

Pictures:

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I will keep working on this in 2 weeks...

zpro
Posts: 49
Joined: Tue Jun 14, 2016 6:23 am
Location: Québec, Canada

Re: 2 x 36" THT LP with front firing mouth

#4 Post by zpro »

So everything is going quite well!

Should be finished tomorrow night. I ran into a few issues with the hardware for mounting the driver to the baffle but I managed to figure it out...

I do have a question:

Is running a 1/2" round over router bit on all the outer edges a bad idea regarding the structural integrity of the speaker? I ask because I know that this may influence the strength of the joints given the fact that the wood is only 1/2" thick...

Anything wrong with leaving screws used to mate parts together within the enclosure there permanently?

I will post pics and impressions! I cannot wait!

Z

Bruce Weldy
Posts: 8301
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: 2 x 36" THT LP with front firing mouth

#5 Post by Bruce Weldy »

Use a 3/8" roundover bit.

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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Tom Smit
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Joined: Sat Jan 05, 2008 1:24 pm
Location: Sarnia, Ont. Canada

Re: 2 x 36" THT LP with front firing mouth

#6 Post by Tom Smit »

Make sure that there are no screw where you plan to route.
TomS

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Bill Fitzmaurice
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Re: 2 x 36" THT LP with front firing mouth

#7 Post by Bill Fitzmaurice »

Bruce Weldy wrote:Use a 3/8" roundover bit.
+1. It won't affect the structural integrity, and it's the standard size for commercial corner protectors.

zpro
Posts: 49
Joined: Tue Jun 14, 2016 6:23 am
Location: Québec, Canada

Re: 2 x 36" THT LP with front firing mouth

#8 Post by zpro »

Fantastic thanks for the info.

I will look into purchasing a 3/8" bit, but would 1/8" more really make a difference? (I already have a 1/2" round over bit and all my other diy speakers have the 1/2" round over on them and it would be great if they could match...)

I will make sure no screws are in the routing line, good call!

Thanks again for everything, the build was actually much easier than I was expecting, my rickety table saw gave me a few problems with one part, requiring 5 different cuts to get it right, but it's not much of a problem since I will use the waste to make all the small pieces in the cover area.

:hyper:

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Bill Fitzmaurice
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Re: 2 x 36" THT LP with front firing mouth

#9 Post by Bill Fitzmaurice »

zpro wrote:but would 1/8" more really make a difference?
No.

Bruce Weldy
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Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: 2 x 36" THT LP with front firing mouth

#10 Post by Bruce Weldy »

The 3/8 bit gives you a little more room to miss brad nails on the edges.

You shouldn't have any screws in the edges. If you used 'em to attach the sides, fine - but take 'em out now. They serve no purpose after the glue dries. And they will destroy a bit. You can hit a brad nail without damage (if you catch a little of it)....but if you go with the smaller bit, there's less chance.

Buy the bit....it's a few bucks....it works....and you don't take a chance of ruining a bit.

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

zpro
Posts: 49
Joined: Tue Jun 14, 2016 6:23 am
Location: Québec, Canada

Re: 2 x 36" THT LP with front firing mouth

#11 Post by zpro »

Ok, I hate to sound annoying, but I would really like to use the 1/2" to please my desire for aesthetic perfection. No brads were used and all screws will be removed from anywhere the router will be used.

I am assuming Mr. Fitzmaurice's "No" means No it will not impact the structural integrity...?

Also, an update on my progress: everything went perfectly until it was time to mount the second side... :roll: :cry: :wall: :wall:

The entire construction was skewed in a really weird direction by almost 1/2"!!! :wall: :wall: :wall:

I can only guess that the table I was building on the entire time was slightly skewed and so the construction was skewed along with it... In the end it was possible to torque it back nearly to perfection and the second side is drying as I type this!

It was a tri-generational effort (grandfather, father son! You can see my grandfather in one of the pictures, he used to build furniture in his heyday. He gave me some good advice along the way.)

Sorry if my english is poor by the way...

PICTURES!!! :hyper:

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Tom Smit
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Joined: Sat Jan 05, 2008 1:24 pm
Location: Sarnia, Ont. Canada

Re: 2 x 36" THT LP with front firing mouth

#12 Post by Tom Smit »

Tri-generaltional. Thta's great! :clap: :clap:
TomS

zpro
Posts: 49
Joined: Tue Jun 14, 2016 6:23 am
Location: Québec, Canada

Re: 2 x 36" THT LP with front firing mouth

#13 Post by zpro »

Bad news!

There are rattles inside!!! :cussing: :cussing: :cussing:

What should I do?

It seems to be quite localized right below the baffle in the middle... Could it be the woofer rubber slapping?

:(

(On the bright it sounds fantastic and unbelievably powerful though!)

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Bill Fitzmaurice
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Re: 2 x 36" THT LP with front firing mouth

#14 Post by Bill Fitzmaurice »

zpro wrote: It seems to be quite localized right below the baffle in the middle... Could it be the woofer rubber slapping?
Could be, but the woofer testing would have revealed that. If it's not that then something, probably a brace, is loose.

zpro
Posts: 49
Joined: Tue Jun 14, 2016 6:23 am
Location: Québec, Canada

Re: 2 x 36" THT LP with front firing mouth

#15 Post by zpro »

Was the baffle/speaker screws apparently! I guess they were not tight enough, rattle is completely gone in all positions.

Sounds fantastic! Thank you so much for the help everyone.

I will log the second one as well.

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