2.5 way walnut speaker build

[JimGore]

Thease speakers are currently for sale here: http://www.avforums.co.za/index.php/topic,4683.0.html

This thread is in response to forum members asking to see the building process. 
I don't have many photos, but I am posting the ones I have.  Will also give a brief description for each.

Basically, the speakers were built using 18mm Birch ply, covered with solid American Walnut.  The midrange is enclosed in a seperate sealed enclosure, while the .5 driver has it's own bass reflex enclosure.  The cabinet sides are curved.  This was done using a process called "coopering", which is similar to the way the old people made wooden barrels.

Pics as follows:

1.  Here are all the strips of wood.  The plywood is at the back (each has a strip of Maranti glued to one end).  In the front are the pieces of Walnut I resawed on my bandsaw.
2.  Close-up of the plywood with Meranti.
3.  The plywood staves being glued to the Walnut strips.
4.  Gluing up one side panel.

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[JimGore]

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1.  This is the side panel after the glue has cured.  Looking at this photo I can recall the smell so vividly.  Anyone who has ever worked American Walnut will know that is has a very interesting smell.  The smell is a bit pungent - it smells dark and strong.
2.  The inside.  The part at the far end is the bottom.
3.  Two sides glued together.
4.  Different angle.

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[JimGore]

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1.  The colour in natural light.
2.  Here I am applying a couple of layers fibreglass to the insides.  This is mostly to seal the wood, but also reinforces it.
3.  Different angle.
4.  Applied some bitumen to the insides.

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[JimGore]

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1.  Here I have added the central brace.
2.  The back of the cabinet before gluing the Walnut piece on.
3.  Gluing the piece to the back.  It is a seriously thick piece of wood.
4.  The result.  Pretty ugly looking here.

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[JimGore]

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1.  Ready for shaping the back.
2.  Shaping done.
3.  Much better looking now.
4.  View of the bottom.

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[JimGore]

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1.  The inside of the cabinet.
2.  Starting to seal the grain of the wood.  This is the first coat of many, many that will be applied and sanded flat to fill the grain.
3.  From the top.
4.  Here I have sanded the first coat down.  Time for the next coat.

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[JimGore]

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Unfortunately those are all the pics I have of the build.  The final result can be seen below.

If you have any questions I will try my best to answer them.

Regards,
Ian.

[Schalk]

Great work Ian. Keep this up and you might yet become a first class yacht builder
Honestly, craftsmanship like this is rare to find. I am in awe.

[JimGore]

Thank you very much sir!

I don't see myself affording a yacht any time soon so I might need to hone my skills and build one 

[GearSlave]

Ian, I'm stumped at how you shaped that back piece of wood perfectly? Surely you didn't use a file (!!) or a belt sander? Would you mind going into some details as to the shaping technique? Also, I see you used multiple pieces to build up the side curve and then you managed to shape that into a proper curve as well. Did you use the same process as the back? It seems like a rather large area to get nicely curved and making a f.up seems waay too easy here.

[JimGore]

how you shaped that back piece of wood

I shaped it to rougly the correct angle with a hand plane.  I left it about 1mm proud, then started with the sandpaper.

I see you used multiple pieces to build up the side curve and then you managed to shape that into a proper curve as well

Start by smoothing all the edges down with a low angle and very sharp hand plane, then switch over to the ROS (Random Orbital Sander) on 100 grit sandpaper.  I am not going to lie to you - it takes about 17 times longer than you expect it to.  Patience is needed.

It seems like a rather large area to get nicely curved and making a f.up seems waay too easy here.

You are right.  That is why I started out with quite thick pieces of Walnut, and not 2mm pieces.  It allowed me to do quite a bit of shaping and sanding without loosing too much sleep over whether I am going to sand through to the plywood.

What worried me much more than the shaping was cutting the driver recesses out.  You ONLY have 1 chance to do it right.  I cut them after the grain was sealed - after the cabinets were completely built, just awaiting the final layers of clearcoat.  You can see in the pics above that there are no holes yet.

I don't know how many people here know it, but I make furniture for clients in my spare time as well.  The only 2 things I don't do are carving, and building dining room chairs.  The techniques I use there help alot when I build speakers - to be honest, the woodworking skill needed to building speakers is much less than building good quality furniture.  No mortice and tenon or dovetail joints in speakers.  When you work with solid wood alot, you get a "feel" for it that sticks in the back of your mind.  From that experience I know how much I can sand, how deep I need to drill, how strong the joints will be if I apply certain techniques, etc.  It also allows you to see and work with angles and curves much easier than you would be able to otherwise.  That is also why I have all the equipment I do - there is no way I can justify all the tools for speaker building alone.

Ian.

[GearSlave]

That is very interesting Ian.

You ever felt the desire to have a bit of a workshop one or two Saturday mornings? Just out of interest? I enjoy working with wood, I just get demotivated too easily. If something doesn't work out I'm very likely to give up on a project that involves woodwork. I'm not like that when working on a piece of electronics for some reason

[alternativeroute]

I left it about 1mm proud, then started with the sandpaper.

  1mm!!! Thats a lota sanding with an orbital sander!!!

What worried me much more than the shaping was cutting the driver recesses out.  You ONLY have 1 chance to do it right.  I cut them after the grain was sealed - after the cabinets were completely built, just awaiting the final layers of clearcoat.  You can see in the pics above that there are no holes yet.

Was any particular reason why you left the driver recess' till last?

After all was said and done what were your final measurements for speaker performance? Also if the measurements have changed since you first did the speaker? I am quite interested in how drivers eventually 'settle'...

[ByronH]

Impressive work Ian! Thanks for posting the build pics, it's educational as always

[MorneDJ]

Brilliant work. I will gladly pay for a few Saturday mornings in workshops. I will bring cash, the meat and beer