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Speaker cab build thread


OldBluesGuy

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Well here goes... :)

 

Let me start off with a little background:

 

1. This build is being done on a budget - nothing real fancy

2. I have some experience with woodworking, but I'm no expert by any means

3. I have a good assortment of power tools, but they're not especially geared towards woodworking - like AJC says, you can build good stuff with lots of different tools, you may just have to spend more time on the project

4. This is my first attempt at a speaker cabinet

5. I will only be using basic techniques

6. I always practice shop safety - safety glasses, ear protection and all guards in place on all machines. I also take my time, measure twice and cut once

7. I will make mistakes on this build, I have already. Fixing them and finding my way back to a successful project is part of the adventure

 

I started out with a trip to the Depot for the lumber: 3 sheets of finished 3/4 x 2' x 4' birch plywood, 2 sheets of 1/2" x 2' x 4' interior grade plywood, 12' of 1" x 1" for bracing and 14' of 3/4" x 1" for attaching the front baffle and back panel. I also grabbed a 6' length of 2" x 1/8" aluminum flat stock to fashion my jack plates.

pic1.jpg

 

to be continued...

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After deciding on my finished size, 18.5" W x 18.5" H x 14.5" D, I planned out my cuts on the 3/4 birch and cut out my shell pieces. I'm building two 1 x 12 cabs, so I just cut twice as many pieces.

pic9.jpg

 

This 3/4 birch plywood looks great and is finished on both sides. A great deal from the Depot at $9.95 for a 2' x 4' sheet. I only have a station wagon, so it's great getting a good deal on the cut down sheets.

pic8.jpg

 

I also cut down the 1 x 1 stock for my bracing. I'm using butt joint construction on this build and I know I'll need to reinforce those joints if I want strong cabinets. Using 1 x 1 might be a little overkill, but I'd rather err on the side of caution and over-build than under-build.

pic10.jpg

 

Here's where I made my first mistake - I figured the length without factoring in any inset for the front baffle. Most speaker cabs have the baffle inset and I like that look. I just forgot. I tend to get caught up in what I'm doing and sometimes rush things a little. I will work off plans next time instead of just what's in my head. I've already figured out how to work around this to get the fit and look I want. I'll save that for now and show later in the build just how I'm going to do that.

 

to be continued... :)

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This sounds cool. I was going to do a stereo 4 x 12, but ended up finding a used one for $100 with (4) Vintage Eminence 75 watters. Those came out and I put in (2) Celestion V30's 60w and (2) G12-75, then re-wired for stereo. The only thing I'm going to do to it (and I'll document it for you guys) is to strip the ugly felt off of it, take off the steel cage screen, and coat it in roll-on red truck bed liner for protection. I might change the hardware to chrome if I can find chrome inset handles. Then I'm going to do a custom fabric grill cloth, trim, and logo. Anyway, Sorry to highjack this thread OBG. Good luck on this one. Sounds cool and can't wait to see the end result because I'll have to do something similar with those (4) Eminence speakers I still have.;)

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Next I went to work assembling the cabinet shells. I like to work using templates and jigs whenever I can as it speeds up production and insures consistency. I started by attaching the 1 x 1 bracing to the bottom sections of the cabinets. These pieces, along with the top pieces were cut 1 1/2" longer than the side pieces. I used a piece of scrap 3/4 as a guide to place the bracing.

extra_pic1.jpg

 

I then applied glue (Titebond) to the side of the brace and clamped it down in place.

extra_pic4.jpg

 

I then tacked the bracing down using my finish nailer and 1 1/2" nails. I repeated this process on the other side of the bottom panel and then on both sides of the top panel. I set up my clamps, set the bottom in place, applied glue to the outward facing side of the braces and the bottom edges of the side panels and set them in place.

pic14.jpg

 

I applied glue similarly to the braces on the top panel and then also on the top ends of the side panels and then set the top panel in place. I used scrap pieces of wood as spacers to position the clamps where they would be most effective, checked for straightness with a speed square and then clamped everything in place. I let the glue set for a few minutes and then tacked the side panels to the braces with the finish nailer.

pic21.jpg

 

Rinse and repeat an hour later with the other set of panels and voila - two finished cabinet shells.

pic26.jpg

 

 

more to come...

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Very little actual progress tonight. I had to spend most of my time tonight on work-related problems - nowhere near as much fun as the build. :rolleyes:

 

The next thing to tackle on this build was the baffles. I was well into rigging up a compass jig for my router when I remembered that the rotary tool I bought last year for a drywall project had a circle cutting jig. I decided to give that a try instead. My shop is in my basement and I share the space with our bulk food storage and the laundry, so generating sawdust is an issue and my router doesn't have an exhaust port. The rotary tool has a 1/8 collet so I figured smaller bits = lots less sawdust than a 1/2 router bit.

 

I measured for center, drilled a hole for the guide pin in the compass jig and commenced to cuttin':

pic29.jpg

 

These tools are very handy for a multitude of cutting jobs. I don't use mine on a regular basis and forget just how useful they can be.

 

The smaller bits are prone to breaking if you try to cut too much material too quickly, so it's best to take your time and make a series of shallow cuts: 3/16" is about as much as you can safely remove with no fear of bit breakage.

 

pic30.jpg

 

It took 3 passes on the 1/2" plywood baffle, but I'm pleased with the result and there was very little sawdust relative to what I would have generated with the 1/2" router bit. The rotary bits don't fling the sawdust as far either, another plus for my shared work area.

 

The result for the first baffle:

pic31.jpg

 

The plan for tomorrow night is to make the fix for my first mistake in this build which will allow me to mount the baffles a little deeper into the cab shell. If that goes well I then hope to cut out the other baffle, drill the mounting holes and mount the speakers.

 

pic35.jpg

 

 

:)

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Everything looks great; except the butt joints. I think you would of been better off with a boxjoint or dovetails.

 

 

Agreed, but that's a little beyond my current skill set, especially given the POS router I currently have. I'll try something more high-tech on the next build. This is my first. Besides, once they're covered in tolex, who's going to know the difference?

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Agreed, but that's a little beyond my current skill set, especially given the POS router I currently have. I'll try something more high-tech on the next build. This is my first. Besides, once they're covered in tolex, who's going to know the difference?

 

The air escaping will know the difference :o. I only have a pos old craftsman router and this dovetail jig: http://www.mlcswoodworking.com/shopsite_sc/store/html/smarthtml/pages/dovetailjig.html,

 

works great; I got a perfect fitting joint on my first test cut :)

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The air escaping will know the difference
:o
. I only have a pos old craftsman router and this dovetail jig:
http://www.mlcswoodworking.com/shopsite_sc/store/html/smarthtml/pages/dovetailjig.html
,


works great; I got a perfect fitting joint on my first test cut
:)

 

How does air escape from a glued-up butt joint? These are going to be open-backed cabinets so will it even make a difference? What's the net effect of the air escaping? Lost volume? Tone? I'm very new at this and only know enough to know that designing a closed-back cab is over my head and not a good choice for a first build.

 

Thanks for the link. I really want to try one of those jigs.

 

 

Thanks.

 

OBG

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Everything looks great; except the butt joints. I think you would of been better off with a boxjoint or dovetails.

 

Not to be a dick, but thats so untrue. In joinery, dovetails are used for their appearance and primarily because they are a self-clamping joint, ie, in manufacturing a properly cut dovetail can be tapped together and then its done (no further clamping, or mechanical fasteners needed)

 

Dovetails in plywood are not normally done. In some high density plywoods like Baltic Birch it is possible (I do it on my lesser priced drawer boxes) but it stillis tricky to machine without chipping.

 

Box joints suffer a similar fate in most plywoods - solid wood is a different story.

 

However, a butt joint reinforced by a cleat as OBG has done (and actually what I did in my own 2x12 build recently) may not be as fancy and pleasing to the eye, but is as strong, and more than likely stronger than either a box or dovetail, and certainly as airtight or better.

 

Thats my professional opinion... now get back to building OBG! :)

 

AJC

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Not to be a dick, but thats so untrue. In joinery, dovetails are used for their appearance and primarily because they are a self-clamping joint, ie, in manufacturing a properly cut dovetail can be tapped together and then its done (no further clamping, or mechanical fasteners needed)


Dovetails in plywood are not normally done. In some high density plywoods like Baltic Birch it is possible (I do it on my lesser priced drawer boxes) but it stillis tricky to machine without chipping.


Box joints suffer a similar fate in most plywoods - solid wood is a different story.


However, a butt joint reinforced by a cleat as OBG has done (and actually what I did in my own 2x12 build recently) may not be as fancy and pleasing to the eye, but is as strong, and more than likely stronger than either a box or dovetail, and certainly as airtight or better.


Thats my professional opinion... now get back to building OBG!
:)

AJC

 

That was kinda what I was thinking but doubt I could have phrased it so succinctly :) I love dovetails but mainly coz they look so damn good on a solid-wood cab!

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The air escaping will know the difference

 

 

 

Haha

I'm sorry.

 

Love Dovetails and I'd definitely use them on a hardwood uncovered cabinet.

They'll also make a stronger cabinet, which may or may not be a factor.

 

For a covered box, I might skip the fancy joinery

but I would not use Tolex. I will use leather.

What does a piece of Tolex cost?

You can get a half hide on eBay for $30 or $40

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Leather, oh yes, I like that!

 

Correct me if I'm wrong but behind the speaker, I believe there must be some sort of hole/vent/outlet on the box. If not the back pressure will not be free movement of the speaker diaphram.

 

Looks good OBJ, not bad for an IT weenie, keep it up!

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On mine, I used a butt joint as well, but used a biscuit joiner and then clamped everything down tight. There aren't any gaps that I could see anywhere, plus, all inside corners were caulked up. Too me, I'd rather have a tight butt joint than a sloppy biscuit joint, which can happen if you don't have the proper gear/time.

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Agreed, but that's a little beyond my current skill set, especially given the POS router I currently have. I'll try something more high-tech on the next build. This is my first. Besides, once they're covered in tolex, who's going to know the difference?

 

 

I built a finger joint jig to use with a table saw and dado blade. It's easy and works great.

 

Check out my head cab build thread that I linked in your original thread if you want to see the jig and get the details.

 

Either way though, there's nothing wrong with a butt joint, especially when you've got it braced up like you did. Using the finger joint with the jig I made is just easy enough for me to do it, and I didn't have to use any internal bracing.

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Man, you gave me a GREAT idea.. I was going to build a 2x12 with 2 16ohm speakers but now i'll do 2 1x12 with a parallel jack on one speaker. I'll have 1 16ohm cab or 2 8 ohm cab in mono! thanks!

 

You're very welcome. That's exactly why I chose this configuration. :)

 

I probably should have mentioned that in the start of the thread. :D

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I built a finger joint jig to use with a table saw and dado blade. It's easy and works great.


Check out my head cab build thread that I linked in your original thread if you want to see the jig and get the details.


Either way though, there's nothing wrong with a butt joint, especially when you've got it braced up like you did. Using the finger joint with the jig I made is just easy enough for me to do it, and I didn't have to use any internal bracing.

 

Thanks. I'll check out the jig later tonight. I can't see any pictures while I'm surfing from work.

 

:thu:

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Leather, oh yes, I like that!


Correct me if I'm wrong but behind the speaker, I believe there must be some sort of hole/vent/outlet on the box. If not the back pressure will not be free movement of the speaker diaphram.


Looks good OBJ, not bad for an IT weenie, keep it up!

 

Bman, welcome to the HCEG forum. Fellow forumites, please welcome Bman. He's a long-time and very good friend of mine - and a master craftsman in his own right in the shiny world of metal. Bman I'm sure you'll find at least one kindred spirit in AJC, who, if memory serves, dabbles in metal fabrication and such in addition to his woodworking, guitar making and musical talents.

 

I can't speak to the internal physics of speaker movement, I have no real knowledge in that area. I've only owned one sealed back cabinet, but it had no porting that I could see. I'm sure somebody in this thread can speak to that. It's not an issue for my builds as they're going to be open-backed cabinets.

 

Thanks for the kind words of encouragement. I look forward to hearing your $.02 on the rest of this build as it unfolds. :D

 

 

OBG

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