Zaph's ZRT Part 2: The Translam Strikes Back

[djn04]

So I started this in a previous thread but thought I would start a new as the build has begun.

I started with this design



and now I've begun the build. I had the birch and MDF CNC'ed locally by Steve at Knight Toolworks. http://www.knight-toolworks.com/ he did a great job at a very reasonable price.











One down one to go. I'll post more pictures as I go along.

[BigguyZ]

I think this is very interesting. One question- why the translam? Are you going to leave it raw, so it's a visual appeal? Otherwise, it seems to me that there's no need for such a complicated build when there are no curves involved in the cabinet design.

I'm eager to know the thoughts behind the design, so please let me know.

[JonMarsh]

It will be very strong and stiff in proportion to the weight- even though in this case he gives up some of the esthetic possibilities other translam designs feature.

[Bent]

pics are blocked from my work address, I'll have to view them lather,.

[TacoD]

I really like the Magico looks. I read somewhere the Magico V3 sides are laminated separately rather than stacked panels where the inner section is cutout.

[djn04]

Yes I'm doing this for aesthetics and I will be leaving it raw with a natural satin finish I think. I really like the look of the magico's and my first attempt at the ZRT's sound terrific but look like a bad high school shop project so I decided to make new cabinets.

I read that somewhere too that the V3's are not made from panels because it would cost too much. I agree that there is a lot of wasted material doing it this way but at the price they charge for the V3's whats a couple extra sheets of BB.

They are much stiffer than the MDF cabinets I made and a good bit lighter as well. Here's a pic of one of the cabinets rough sanded.

[Operandi]

That looks pretty sweet, and I'm sure it's an incredibly strong structure.

I want to build a small set TMM curved of translam mini-monitors with the RS128, and RS28. I was originally thinking I would veneer them but I kinda like the look of the raw Baltic birch.

[JonW]

They look wonderful. :T

Very nice workmanship too- hardly any extra glue oozing out the sides and you've got them lined up very well (good idea with the dowels).

And with that pairing of drivers they will sound stunning. These speakers will be just super. :B

[djn04]

They look wonderful. :T

Very nice workmanship too- hardly any extra glue oozing out the sides and you've got them lined up very well (good idea with the dowels).
:B

Thanks. Having the dowels makes it very easy. I built both cabinets in 1/10th the time it took me to make the MDF cabs. For those without tools or room to work this is the way to go. They lined up really well and I wiped up the excess glue as I went but I still had to spend a good amount of time with the sander getting everything smooth.

I'm trying to figure out what to do with the voids. I think I might fill them with black epoxy.

[Blktre]

Im interested in how the baffle was made.

[djn04]

Im interested in how the baffle was made.

I designed everything in Sketchup and then had it cnc routed. The baffle was a 3d file but it's really no different than the rest it just takes longer to cut it.

[djn04]

Now on to the baffles. I need to figure out a way to recess the holes for the bolt heads on the curved face. Not easy. I have a forstner bit but using it on a curved surface will be tough.

I'm going to put threaded inserts into the cabinets and bolt the baffle to the cabinets.

[jkrutke]

Well, if you have a drill press, it shouldn't be too hard to use a small diameter forstner to make a countersink. Forstner bits with a hand drill probably aren't going to work though, so I hope you have a drill press. Clamp it well.

Cool cabinets and baffle. I'm a little unsure of what those driver countersinks will do to the response curve, so if you get a chance to measure them, go for it. Otherwise, just let us know how they sound.

[djn04]

I really like the Magico looks. I read somewhere the Magico V3 sides are laminated separately rather than stacked panels where the inner section is cutout.

I found it. It was in the Absolute Sound review. "Second, the Mini’s cabinet construction is over-the-top; sheets of birch ply are machined into a shape that includes the internal ribs, and then glued together into a solid block to produce a structure of unparalleled rigidity—and unparalleled expense. The V3’s cabinet is still made from birch ply (Wolf rejects MDF as a cabinet material—see the accompanying interview), but is built differently. The sheets of birch ply are cut into 1.5"-thick strips which are glued together to create the enclosure.1 Between the cost savings of this technique and cutting out the expense of stands, Magico was able to deliver a three-way, floorstanding loudspeaker with same drivers as the Mini for less money."

I can't believe that it was because of cost that they built them that way. The baffle is made from 1" aluminum which would cost more than the birch ply I would think.

[djn04]

Well, if you have a drill press, it shouldn't be too hard to use a small diameter forstner to make a countersink. Forstner bits with a hand drill probably aren't going to work though, so I hope you have a drill press. Clamp it well.

Cool cabinets and baffle. I'm a little unsure of what those driver countersinks will do to the response curve, so if you get a chance to measure them, go for it. Otherwise, just let us know how they sound.

I don't have a drill press but the guy who did the cnc for me does I might have to ask him if I can use it.

As far as measuring all I have it an Audyssey mic and FuzzMeasure. I'm not sure how accurate that would be, but I'll try to make a comparison to the cabinets I built which are to your specs.

[Undefinition]

Wow. At first I didn't understand the appeal of a birch laminate rectangular cabinet, but after seeing that beautifully square edge, I have to say that looks awesome!

[Smokinghot]

Wow. At first I didn't understand the appeal of a birch laminate rectangular cabinet, but after seeing that beautifully square edge, I have to say that looks awesome!

Ya, I'm going to have to agree with you there.

Normally I'm all about the round-overs, but definitely not in this case. The square edge sells the vertical Translam. :T

[JonP]

I read that somewhere too that the V3's are not made from panels because it would cost too much. I agree that there is a lot of wasted material doing it this way but at the price they charge for the V3's whats a couple extra sheets of BB.

Hope you got the scrap pieces back... bet you could make 4-5 pairs of Zaph's Budget Monitors or similar out of them! :B

Really looking great... can't wait to see them in final finish. I like BB a lot, and the endgrain look is one of the reasons. Not sure of your finishing plans, but a coat or two of Zinnser's Sanding Sealer (the dewaxed shellac) can pop up the the grain nicely before you topcoat it with whatever.

The alignment dowels are a very good idea... I've seen a few laminated projects where they were hand placed, which usually results in enough alignment error that you need to sand off 1/4" to get the whole thing flat again.

Also not sure which sanding technique you're using... (though it's coming out great) I got a great tip once to buy the biggest sanding belt size, (6"x48") cut it into two strips (not like me, make sure you cut out the seam) and glue/tape them spaced a bit, side by side, onto a big piece of MDF... Tada... a giant lapping plate/sanding block/poor man's oversized sander! Cheap and effective, for flattening PERFECTLY, large areas like box sides. And it's good excercise, too... :B Smaller boxes you can lap back and forth on the plate, something like this you might rub the plate over the faces... Might be a help to groom those faces to perfection...

On filling the BB gaps, you might try gathering some of the large amounts of sawdust, and mixing with wood glue for a putty, as a hole filler. Might not look so good, might make a near perfect match. Try it on some scrap pieces.

Awesome box for a awesome design... what's not to like??

[---k---]

Very cool. I'm most intrigued by the curved baffle. Very elegant. I'm looking forward to seeing how the drivers sit in the holes. Too bad we can get a measurement to compare what it does to the baffle diffraction.

[chasw98]

Really nice looking work. I am very envious of the curved front baffle. That will look reallly, realy nice! How did you locate a shop that would do the MDF CNC work? The company I work for has approx. 30 CNC machines but all we do is metal work, not wood. The edges of BB came out much better than I thought it would in my head.

Chuck

[djn04]

Also not sure which sanding technique you're using... (though it's coming out great) I got a great tip once to buy the biggest sanding belt size, (6"x48") cut it into two strips (not like me, make sure you cut out the seam) and glue/tape them spaced a bit, side by side, onto a big piece of MDF... Tada... a giant lapping plate/sanding block/poor man's oversized sander! Cheap and effective, for flattening PERFECTLY, large areas like box sides. And it's good excercise, too... :B Smaller boxes you can lap back and forth on the plate, something like this you might rub the plate over the faces... Might be a help to groom those faces to perfection...

Great tip I wish I had know this before! I used an electric palm sander. Each side took about an hour I would say. My arms are so sore I can barely lift them today. I think I may make one of these just to get everything perfectly flat before finishing.

About finishing I like the idea of bringing out the end grain and I want the lightest satin finish I can get on them.

[djn04]

Really nice looking work. I am very envious of the curved front baffle. That will look reallly, realy nice! How did you locate a shop that would do the MDF CNC work? The company I work for has approx. 30 CNC machines but all we do is metal work, not wood. The edges of BB came out much better than I thought it would in my head.

Chuck

I just asked around at local woodworking supply stores and one gave me the name of a local guy. His machine was a ShopBot that could cut from 4x8 sheets. He said it could do aluminum and acrylic as well. The software was Vcarve I think.

His name is Steve http://www.knight-toolworks.com/ and if your in Portland, OR he does great work for a reasonable price. He showed me a case for a headphone amp routed from a solid block of walnut that was really cool.

[gmed]

I would definitely not leave it raw without some sort of clear coat. I used Polyurethane rub on clear on my translam and it looks amazing.

leaving it raw, it would get dirty eventually.

Its nice that you had them cut. My first one took one year to complete part time.

[djn04]

My next question is about finishing the curved portion of the baffle. I want to paint it black with the most durable finish I can.

My plan is to seal it with wood hardener and a thin coat of bondo to give it a smooth finish. I would like the finish to resemble anodized aluminum. So I'm thinking some sort of matte/satin/eggshell finish in black. Does anyone have a suggestion for a durable finish.
Thanks

I just ran across this also. Has anyone tried power coating MDF?

http://www.tiger-coatings.us/index.php?id=1363

[Amphiprion]

Wouldn't this technically be a longitudinal, instead of a transverse, lamination? Aka a "Long-lam"? [/engineer]

[technimac]

I want to paint it black with the most durable finish I can.
... I would like the finish to resemble anodized aluminum. So I'm thinking some sort of matte/satin/eggshell finish in black. Does anyone have a suggestion for a durable finish...

You mean something like this?



I explained the process in this post:

https://www.htguide.com/forum/showpost.php?p=289333&postcount=599

Very durable finish. It looks black in certain light and has that gunmetal grey patina in other light.

HTH, Bruce

[djn04]

Bruce-
That's exactly what I want the look to be. General Paint is only sold in Canada though. I wonder what kind of substitute I can find around here.

[Lewisimo]

dude, those ^ speakers are awesome!!

[Dennis H]

I think the key thing in Bruce's finish is the clear satin poly over the black. You could use any black paint that would stick to the poly.

[technimac]

Thanks for the kind words about the Modula TM's.
Dennis is on the right track.
I shot the finish on using a Rockler HVLP gun. The flat black surface was very soft and almost "chalky" - not very durable at all. I very lightly sanded that with wet/dry and super-fine 3m pad.
When I sprayed the Varathane satin poly, all went well as long as I maintained motion and kept the nozzle a good distance from the baffles.
On two, runs developed, 8O so I wiped off the poly right away, let them dry for 15 minutes and successfully reshot them.
I think the nature of the flat black base coat just may have something to do with the metallic patina because of its ability to absorb light. Can't say for sure because I haven't used Varathane satin poly with any other black base coat such as gloss, semi-gloss or satin. Now, that would be an interesting experiment to carry out.
I do have to say that the Varathane satin finish is very durable and easy to wipe clean with a damp cloth. In the USA, Varathane is under the Rustoleum banner and I understand their products are widely available. BTW, their water-based poly is referred to as " Interior Diamond Polyurethane" on the label.
HTH,
Bruce

[kabeer_g]

Now on to the baffles. I need to figure out a way to recess the holes for the bolt heads on the curved face. Not easy. I have a forstner bit but using it on a curved surface will be tough.

I'm going to put threaded inserts into the cabinets and bolt the baffle to the cabinets.

Have you decided how you will finish them. That's something I am really struggling with.

What do folks think of mixing transtint dyes with Deft Water-Based Clear Wood Semi-Gloss lacquer and doing 2-3 coats of that?

[---k---]

Wouldn't this technically be a longitudinal, instead of a transverse, lamination? Aka a "Long-lam"? [/engineer]

Funny guy!

In the world of Engineered Wood, beams made with horizontal laminations are "Glulams" and the ones with vertical laminations are "Parallams". Those are technically trade names, but what everyone calls them.

:P

[technimac]

...beams made with horizontal laminations are "Glulams" and the ones with vertical laminations are "Parallams".

Uhhh, well actually, Parallam is not necessarily oriented vertically, but most of the veneer (~1/10" thickness) is parallel.
This is an excellent product that uses the waste material from plywood manufacturing. :T
Here's a good image:

Image not available

Key thing is that Parallam is composed of strands of veneer.

Glulam, OTOH, is made up of layers of dimensional lumber (2"x4", 2"x6", etc.) and for sure, these layers are horizontal - but not necessarily the "grain" :W .
I used a number of these (years ago) in the construction of my home.

[Amphiprion]

What I would love to see is a laminated speaker built-up like they build aftermarket gun stocks. Combination of ~1/16" thick hardwood planks dyed to look anywhere from natural to psychedelic.

http://www.rifle-stocks.com/laminated_woods.htm

But I think this would be way to costly for a speaker build. Dying each individual layer would be overly tedious and getting widths adequate for a speaker build would be nigh impossible.

[djn04]

Little Update. The baffles are on.

[Eric89GXL]

That looks awesome. Good work. Can't wait to see the finished product.

[tpremo55]

Those speakers look great!
You had the Baffle CNC'd as well - right? If not, I'd be interested in your technique. Would also be interested to see if there is a measureable impact of the recess as John had mentioned.

[djn04]

The baffles were CNC'd.





The paint looks terrible up close and not all the holes and threaded inserts are not lining up. :M

[Tsloms]

Those are just plain cool looking speakers. How many sheets of plywood did it take to make that pair?

[Chris7]

Love how these turned out! You'd definitely get the award for best-looking DIY speakers that I've seen this year.

[djn04]

Those are just plain cool looking speakers. How many sheets of plywood did it take to make that pair?

It took 3 sheets of "Baltic" Birch. It is Russian birch but at a cheaper price than Baltic birch. It's better than the dragon birch stuff and better than a lot of the real Baltic birch I saw. The only stuff I saw that looked better was apple wood ply. It's some sort of English wood or something but it was 130 a sheet. This stuff was less than half the price.

[djn04]

Love how these turned out! You'd definitely get the award for best-looking DIY speakers that I've seen this year.

Thanks. I'm glad you cant get a good look at the paint though. I still need to finish the cabinets. I think I'm going to put a coat of Benite on them to bring out the contrast in the layers and then finish them with a clear satin polyurethane.

My only problem is the threaded inserts don't line up with the holes on the baffle. I drilled the holes in the final layer of plywood before gluing them to the cabinets and when I glued them I think the dowel rods pulled the sides in just a tiny bit and now the holes don't line up.

I might remove the inserts and fill the holes with bondo then redrill them. Will this work? Does anybody have a better idea?

[---k---]

It should. You're just talking about filling the small holes in the baffle, right? Bondo is recommended around here all the time. I used it on my old subs. Not sure how much deep of a bondo you can place in one step. I wouldn't want to try and fill 1" deep at a time. You could always cut a piece of wood dowel to length and epoxy it in there.

[JonP]

Great tip I wish I had know this before! I used an electric palm sander. Each side took about an hour I would say. My arms are so sore I can barely lift them today. I think I may make one of these just to get everything perfectly flat before finishing.

About finishing I like the idea of bringing out the end grain and I want the lightest satin finish I can get on them.

Yeah, wait till you lap them for an hour or two. You're going to have to learn an Austrian accent, to go with your new forearms and biceps... :W

On the finishes, I hear that water based poly's tend to stay glass clear, while oil based ones get a bit yellow with age...

Heh, I was going to point you to Technimac, for a black satin finish. That Modula MT of his was the first thing to pop into my head when you described the look you were after... :B

Great to see the project moving along...

[djn04]

It should. You're just talking about filling the small holes in the baffle, right? Bondo is recommended around here all the time. I used it on my old subs. Not sure how much deep of a bondo you can place in one step. I wouldn't want to try and fill 1" deep at a time. You could always cut a piece of wood dowel to length and epoxy it in there.

No it's the opposite. I want to fill the holes were the threaded inserts are. If I fill them with bondo will I be able to redrill the holes a fraction if an inch from where they are and reinsert the threaded inserts?
Thanks