Three Way Evil Design Study

[JonMarsh]

That's what makes this place so interesting. You never know what you're going to learn or how the lesson is going to be presented.

Keep streaming Jon.....you're the man. ;x(

Well, we DO always want things to be interesting, and sometimes that follows from wandering a little bit off topic to something that is nevertheless related! Or relevant- or just comes up in the dialog. Dialog is good... :T

[cjd]

Excellent progress Jon, I am impressed you managed to get all of your cutting so accurate in the absence of a CNC machine I guess I cheated in my case Keep the photos coming so I can get excited in the absence of my cabinets. I'm going to be cutting in fine between getting cabinets back and drivers mounted before I need to pack them up for my pending move the Chicago. It might even introduce a convenient "crossover" buffer time

Chicago eh? I might know someone around here with some tools and experience on the crossover and measuring side of things. OK, a good few folks. We've got you covered, north or south...

Progress looks good Jon. I've been enjoying the hand fitting for some reason. Slow work but a good end to a day. Usually just one brace an evening. I evidently don't have a big enough table for accurate dado cuts on angled panels. 1/16" off at times.

[JonMarsh]

Chicago eh? I might know someone around here with some tools and experience on the crossover and measuring side of things. OK, a good few folks. We've got you covered, north or south...

Progress looks good Jon. I've been enjoying the hand fitting for some reason. Slow work but a good end to a day. Usually just one brace an evening. I evidently don't have a big enough table for accurate dado cuts on angled panels. 1/16" off at times.

Completely in agreement, Chris -

Now I'm trying to find an hour every evening just to do one more step as cleanly as possible- in the end, over the course of a week, I figure I can get as much done as on one weekend day, and have more time to mull things over between steps. Some days, like today, with regional biz travel and seeing my GF tonight, there's no time, but still it seems to be a rhythm that works well. Plus in this gluing stage, I get much more done than is possible just on the weekend, considering full setting time on the epoxy I'm using.

[Hank]

Thanks for blue tape useage, Jon! Our stock took a recent dip, so every roll helps. ;x(
Have you used epoxy on compound angle joints before, or is this a first?

[JonMarsh]

Thanks for blue tape useage, Jon! Our stock took a recent dip, so every roll helps. ;x(
Have you used epoxy on compound angle joints before, or is this a first?

Closet thing in the past was the X-1 SLAMM klones, but they were straight 90 degree cuts for the bevel angles, not compound angles like these. And they did use epoxy. So did the Ardents. Titebond for laminating panels, though.

You know what they say, anything you survive makes you stronger (and presumably smarter... Such as smarter than digging such a deep hole (challenge) to climb out of…)

These upper modules should be really stiff when finished!

Also worked on the internal cable plan last night…

[JonMarsh]

Additional 3M equipment in use

Glued up second sides this afternoon; note the same disposable blue strap clamps, but also another essential piece of equipment, 3M ear protectors to reduce the muttering and cursing as pieces are brought into alignment...

[johngalt47]

LOL!

I love it! ("...to reduce the cursing and muttering...")

...but seriously, you have given me an idea of how to hold the mitered sides of my cab together while the glue is drying...

[Hank]

Blue painter's tape rules! (Don't forget 3M dust masks when cutting) -Shameful as well as scurrilous ops:

[JonMarsh]

TGA clamping

If the muttering and cursing has gone well, and full TGA* has been in progress for the earlier assembly steps (* TGA = Teeth Gnashing Accuracy) :roll: , then this is how much clamping is needed for the top piece gluing.



the Combo Backwall support and side to side braces are glued in next...

[cjd]

you may as well have just gone full translam!

[JonMarsh]

And now a word from our sponsor...

What do you do when it's the middle of a Sunday afternoon and you need to install WhisperMAT in your latest project? If you're me, you don't work up a sweat, you just reach for the 3M 90 Spray adhesive! 3M 90 solves those difficult adhesion problems with tough to glue materials- it helps me quieten down my cabinets and gives me peace of mind that my adhesives won't let me down! :B



Don't accept any substitutes if you want YOUR next DIY speaker project to be the project of your dreams! :T

[5th element]

I've always used 3M spray mount for pictures/photos when gluing printed templates to MDF/plywood, before trimming/sanding the wood to match, I guess this is just the 'industrial' strength version. One wonders if you could glue veneer with it? Or is it not that strong/too expensive?

[Hank]

I'm getting misty-eyed here. :cry: I'm gonna send you boys rolls of blue painter's tape for Christmas.

[JonMarsh]

I've always used 3M spray mount for pictures/photos when gluing printed templates to MDF/plywood, before trimming/sanding the wood to match, I guess this is just the 'industrial' strength version. One wonders if you could glue veneer with it? Or is it not that strong/too expensive?

3M 90 and 3M 77 are two I frequently use, and you can get them at your local big box stores; 90 is specifically formulated for plastics that are difficult to glue with conventional adhesives, including polyethylene. 77 is a bit more general purpose. Both are contact adhesives, that is, you spray both surfaces, and let them dry to tacky, 2-5 minutes, before mating the parts.


Made some good progress, including installing the WhisperMAT in the top modules, fabricating the new top module backs sans holes for a binding post plate (change in wire routing plans- a secondary mid/tweeter plate will be in the bass, above the main binding post entry. - these will be used for measurements and/or extra shunting networks; will be connected to the crossover outputs when system is completed and crossovers mounted internally.

Did the side cross cuts for the bass module left and right walls, and ripped the lamination pieces for the back walls, to glue those up and get ready for cross cuts (love the DWS780). Finished the lamination for the bass module tops and lower alignment braces; now need to rip and cross cut those. Dug out my big cache of Deft lacquer and sanding sealer... guess I'm going that way, for the UV protection. GF has offered to let me turn her garage into a spray booth one weekend.... little does she know! We'll have to be sure her Porsche 356 is well away from the action. (there is a quid pro quo, here, as up coming project is a much needed full insulation re-do for her attic).

Also played around with some "concept engineering" of crossover approaches, including one derived from the Modula MT/NatalieP which is interesting, though in the end I think it has the treble signal going through too many caps. Reworking that idea; but still attracted to the notion of using a 3rd order LR (used in a quasi-series/parallel in NatalieP and ModulaMT). Has a nice all pass characteristic (unlike B3 with it's phase quadrature) with a bit more protection for the tweeter, and more upper range attenuation for the midrange, without going to an LR4. It's worth looking at more, and comparing to a Duelund approach.

all in all, was a productive weekend.

[JonMarsh]

A nightmare...

you may as well have just gone full translam!

Well, if I had one of these, that might have been feasible... 8O





But I don't, and just four layers for the front panel was interesting enough! The whole thing in Translam would have been an unending nightmare, I fear... and VERY expensive in LBL! :M

[JonMarsh]

I love my DWS780!

It is such a pleasure to work with.

Had an hour this evening after work (started very early !) and cut the bass cabinet top plates and bottom alignment plates- the combination of that saw plus the top of the line DeWalt 12" blade (which did NOT come with the saw!) are a real pleasure to work with!

Oh, and the backs are glued on the top modules, which is for me a big milestone- Man are they solid! Especially with the center brace connecting the back and both sides. There's a lot of detail work to finish them up, but now I'm starting to be able to imagine having enclosures before too long. Especially with vacation time for the whole Thanksgiving week approved today!

[Face]

It's down to $494 on Amazon right now...saw one for $100 more at Home Depot.

[Hank]

Well, if I had one of these, that might have been feasible...

Jon: shame on you for posting that tool porn :drool:
If I had one of those beauties, I would be so tempted to get back into speaker-building when I retire in a year or two...

[JonMarsh]

Jon: shame on you for posting that tool porn :drool:
If I had one of those beauties, I would be so tempted to get back into speaker-building when I retire in a year or two...

Well, they're on sale at Rockler- here's your chance! You should always be planning for retirement, putting away the resources you'll need! :B :T

[CraigJ]

Jon: shame on you for posting that tool porn :drool:
If I had one of those beauties, I would be so tempted to get back into speaker-building when I retire in a year or two...

Hank,

You'll only need a hand saw and some chain for your next project;



Stig Eirc's RD-75 system.

[Hank]

Craig, you are soooo encouraging :B
Hey, I've got 3 routers, a large router table, table saw, drill press, misc power and cordless tools and a bunch of clamps. Doesn't hold a candle to Jon's goodies - he must have half a dozen routers and a gross of clamps, and portable table saw, his new compound sliding mitre saw, etc, etc, etc :

[JonMarsh]

Craig, you are soooo encouraging :B
Hey, I've got 3 routers, a large router table, table saw, drill press, misc power and cordless tools and a bunch of clamps. Doesn't hold a candle to Jon's goodies - he must have half a dozen routers and a gross of clamps, and portable table saw, his new compound sliding mitre saw, etc, etc, etc :

Hey, I resemble that remark!

Now seriously Hank, even counting my Freud router table with a Bosch router mounted and all my mini routers (Bosch Colt, DeWalt DWP611) I only have, um, 10 routers, and they're all setup for specific jobs and functions- grab them off the shelf and go to work! I mean, it's not easy to be productive, and setting up and tearing down routers would just be one more problem.

Gross of clamps, that's pretty much true, even just counting the good stuff (Bessy's). But gee whiz, you can't put EVERYTHING together with just blue tape! :B

My new DWS780 really is the cat's meow- it stomps my 10" Hitachi compound bevel miter saw, which while well made, just doesn't have comparable capabilities. I even looked at their biggest, baddest 12" version, and it's just not in the same league.

And I still love my DW745- the best portable table saw made, IMO; I just wish they made a bit bigger version of this, but if you can build an Isis clone with it, I suppose that should be good enough for most folks- I love the fence. The Rack and pinion design has worked very well and is very accurate.

[CraigJ]

Craig, you are soooo encouraging :B

Speaker porn, now tool porn? :boobies: Oops, back to work!

Hank, I figure that you've been such an excellent motivational cheerleader for John in finishing his Kleos array that I'm going to get you started on your own array build. Have we decided on the RD50 or the RD75?

Hope this helps and sorry for the side track Jon. Off to install a pair of my own NS12s :dothewave: Go Hank, go Hank.....

[JonMarsh]

Craig, I agree that's a great idea to encourage Hank! No problem side tracking this thread in order to do it!

As for the Kleos array, John's getting real close! :td:

:dancenana:

Go Hank!!! :dothewave:

[Johnloudb]

:dothewave: Go Hank, go Hank.....

I third that! Go Hank!!! :driver:

[5th element]

Man this forum certainly has no lack of smilies

[JonMarsh]

Bass module front panels upper bevels cut today. Center braces cross cut to length and angles.

Will do bottom bevels tomorrow AM when I'm more rested - been up since 4 AM. Early work stuff, European conference calls. Will do detail work on interior braces tomorrow, then should be ready to start gluing up bass modules on Sunday.

Woo hoo! :dancenana: :dancenana: :dancenana: :dancenana: :dancenana:

[JonMarsh]

Hah! Talk about optimistic!

Wheel, I did get a lot of detail work done on bass module pieces, but spent most of Sunday packing for my business trip to Minneapolis!

[Hank]

Thanks for the words, boys. Alas, I've been hearing the siren song of planars of late - reading up on the history of Acoustat, Appogee, Bob Carver, and of course considering Maggies. Intriguing how Acoustat and Carver worked so hard at integrating dynamic woofers with electrostatic panels. Quite different, non-standard requirements to get the correct "Q" - super thin cones and light suspension, etc, etc. Hey, I even made on offer on a pair of supposedly unused Acoustats on eBay. So, a pair of used hybrid ESL's - mate a proper servo woofer is a possibility. A pair of Maggies - build hardwood frames. New, Jon-inspired crossover components for whatever........then there's the new intriguing NEO 10. So many forks in the road.... :crazy:

[JonMarsh]

Thanks for the words, boys. Alas, I've been hearing the siren song of planars of late - reading up on the history of Acoustat, Appogee, Bob Carver, and of course considering Maggies. Intriguing how Acoustat and Carver worked so hard at integrating dynamic woofers with electrostatic panels. Quite different, non-standard requirements to get the correct "Q" - super thin cones and light suspension, etc, etc. Hey, I even made on offer on a pair of supposedly unused Acoustats on eBay. So, a pair of used hybrid ESL's - mate a proper servo woofer is a possibility. A pair of Maggies - build hardwood frames. New, Jon-inspired crossover components for whatever........then there's the new intriguing NEO 10. So many forks in the road.... :crazy:

Life is about the possibilities, Hank..... :T

[JonMarsh]

Tiny teaser...

Back from my trip to Minneapolis this week, and now making a bit of progress, though side tracked this AM by Thanksgiving preparations.





Initial sanding completed following the bevel cuts; I still have to plan the grille cloth frame and locate where I'll be installing Neodymium magnets in the front panels to support the grille frames.

If you think the woofer rebates look a little deep, it's because they are, in order that under excursion the woofers won't kick the front grille frames (hopefully! :roll: )



Using Mirka Abranet pads in the Porter Cable sander, I REALLY like those, as the pass through for air and dust is built in to the sanding pad design. Pretty unique construction.




Well, back to work- next up is routing out the braces.

[sdl2112]

Looking great Jon...good thing bamboo grows fast :W

You have me fooled that you say you are not a woodworker...I'm walking on pins and needles with every cut I make. Interesting you are making grills...can't wait to see how you make them.

Scott

[Paul W]

If you think the woofer rebates look a little deep, it's because they are, in order that under excursion the woofers won't kick the front grille frames (hopefully! :roll: )

Like the idea...should reduce flow restriction at the back of the cone too!

:T

[JonMarsh]

Looking great Jon...good thing bamboo grows fast :W

...I'm walking on pins and needles with every cut I make.

Scott

Ditto here, especially the further I get, the bigger the impact of "yield loss" if I screw up. Especially with expensive material like the LBL and phenolic sheet. Plan and measure half a dozen times before cutting!

[JonMarsh]

Like the idea...should reduce flow restriction at the back of the cone too!

:T

Back side is strongly chamfered, too, for the same reason.

[gbegland]

Yeah Baby!

[JonMarsh]

Sunday Teaser

Base sanding for Top modules in progress.... these still need some filler for the inner core ply defects and some other surface defects, plus Behlen pore filler.

you know, we just may have some speakers once this is all done. For a while, it's been an effort to see that!











Finally having some nice weather today - makes it possible to get stuff done!

Now, back to bass module brace fabrication!

[dar47]

Looking good!

Angles angles, see angles everywhere.

Are you using epoxy filler for joints and voids? The water or oil based Behlen? Don't you have to put some stain over that filler?

[JonMarsh]

Looking good!

Angles angles, see angles everywhere.

Are you using epoxy filler for joints and voids? The water or oil based Behlen? Don't you have to put some stain over that filler?

The main joints for assembly (not lamination) have all used System Three T88. What I've found is that there are small voids now and then in the inner LBL core- the inside layer- so I plan to deal with those with System Three SculpWood, which is a two part kneadable wood filler (sort of epoxy based).

Behlen Pore-o-Pac natural is pretty good for filling and leveling open grain woods, and this fossilized bamboo ply outer surface is more like, say, oak, than like Maple, (it seems to be shredded bamboo mixed with binder resins) so it needs something to make a level surface for finishing.

The other alternative is System Three Silica powder mixed in with Lacquer sanding sealer- (which I've got on hand, too) I've got enough moderate sized scraps that I can test these approaches soon and decide which to go with.

I'm not planning on going with any stain; considering how maple develops clarity in the grain and appearance just with sanding sealer and clear lacquer, I'm expecting something like that with the fossilized bamboo.





Like I say, I'm no experienced woodworker, so my tendency is to proceed cautiously and test evaluate on scrap before proceeding.

[JonMarsh]

Monkey Coffin dry fit check passed

OK, it's been sweaty palm time, finishing up detail work on the braces, biscuiting the front panel, top piece, bottom brace, and sides, and then doing my first dry fit check for a bottom module.



For now, just laying down the braces to check the side to side spacing (by the way, it pays to round over the LBL, because a straight 90 degree corner in bamboo is SHARP! Skin cutting sharp!)



Nothing but a skosh of the finest blue tape holding these together for a dry check



Houston, we have a go for launch pad assembly... :T break out the T88 structural adhesive! :B But let's hold off on the champagne for now- maybe just some French Blood Orange soda to celebrate (yeah, not in the same category as a fine tequila, but we've got assembly operations ongoing... )

[Steve Manning]

Monkey Coffin dry fit check passed

OK, it's been sweaty palm time, finishing up detail work on the braces, biscuiting the front panel, top piece, bottom brace, and sides, and then doing my first dry fit check for a bottom module.



For now, just laying down the braces to check the side to side spacing (by the way, it pays to round over the LBL, because a straight 90 degree corner in bamboo is SHARP! Skin cutting sharp!)



Nothing but a skosh of the finest blue tape holding these together for a dry check



Houston, we have a go for launch pad assembly... :T break out the T88 structural adhesive! :B But let's hold off on the champagne for now- maybe just some French Blood Orange soda to celebrate (yeah, not in the same category as a fine tequila, but we've got assembly operations ongoing... )

Man after my own heart ..... lots of biscuits !! Your a braver man than I am though, going more or less to the finished cabinet right of the bat. I need some wood putty or veneer to cover up the imperfections. That bamboo does have a nice look to it though.

Steve

[JonMarsh]

Brave or foolish... we'll see which one it is in the end! :W

The fossilized bamboo has a very high surface hardness, so it's easier to work with than something like pre-veneered particle board, which I used to work with in the 70's. veneered MDF makes me nervous now, because of how "soft" it is compared with the bamboo ply.

[dar47]

Looks great, Jon

Is the pass through brace, top,bottom and back lined with MDF for damping?

[JonMarsh]

It's for structural design convenience-

The sides, I wanted 1" with a 1/4" rebate 1" deep for fitting the back; adding 1/4" MDF and rebating was the easy way to do it. The back I also wanted 1" thick, but planning to add rebates on the inside for the Vampire binding posts.



Similarly, for the center brace, I needed 1-1/4" in order to get the side braces at or below 6", for reasons of material availability- adding two 1/4" layers to a 3/4" LBL ply did the trick.

The top and bottom panels are actually "cheaters"- BB ply I had around that was already laminated on both sides with 1/4", but not used for the intended project.

The actual base plate is two layers of 3/4" LBL.

[dar47]

Ah, the method of your madness.

I think your going to be vary pleased with this well planned and implemented cabinet work, it should rank up there with your best work. I hope these are keepers for your listening room and not just a short while?