Boinger's Bordeaux Build

[boinger]

Started on the Bordeaux Build.

Had a question about the baffles. Since we have to sandwich 2 sheets of ply together. How do most handle that do you glue them first and then route or route first then glue together?

I wasn't sure on how to line up the inner and outer baffle when not on the actual speaker box. I am guessing it has to be pretty spot on when gluing or it wont fit.

[Bear]

Depending upon what is needed, you should almost always route and then glue for driver holes. Chamfering/rounding edges are usually done after glue-up.

[boinger]

I see thanks for your input.

In case I wasn't clear I meant only gluing the two baffle pieces not the entire speaker, but Jim also mentioned that he does them individually as well.

[Jim Holtz]

I'm looking forward to following your build! :T

Jim

[Steve Manning]

You can also use a few alignment dowels between the two layers so things don't move when you glue things up.

[boinger]

A little progress

A little progress

Got all the boards ready to be routed tomorrow. All baltic birch.

Hopefully we can glue it up too

.

[boinger]

some more progress

Quick question I went to shallow on one of the baffles during my routing. What would be the best way to deepen the cut? I was thinking cut a circle from some scrap would shove it in the hole that I cut through on the baffle. Then reroute the correct depth using the jasper jig.

Also on the other baffle my router went 1/8 inch too deep. Could I just fill in the back since the other 1.25" is the correct depth?

Let me know your thoughts. Another picture attached.

Edit: Anyone know why my pictures keep getting rotated?

[Bear]

Quick question I went to shallow on one of the baffles during my routing. What would be the best way to deepen the cut? I was thinking cut a circle from some scrap would shove it in the hole that I cut through on the baffle. Then reroute the correct depth using the jasper jig.

This is where we don't look too closely at budget... Your easiest fix may be to grab a rabbeting bit from your preferred dealer. Think of it as a large, but shallow, two flute straight cutter with replaceable bearings on the bottom. You control the width of the cut by changing out the bearings (larger bearing equals a shallower cut). Since it also can do depth, this is probably the easiest way to go.

Also on the other baffle my router went 1/8 inch too deep. Could I just fill in the back since the other 1.25" is the correct depth?

3mm felt or some other gasketing material, and you are good to go.

[boinger]

I don't think the rabbit bit can cut deep enough. I think the woofer section needs a 1.5in counter sink. Not finding a rabbit bit that will cut that deep.

[Jim Holtz]

Repairing mistakes isn't one of my strengths. I usually simply start over so I'm glad Bear jumped in and gave some ideas.

I usually measure the driver, cut the recess 1st, verify the recess is the correct diameter and depth, then do the final cut out for the driver. Check for accuracy with one of the drivers to make sure it fits as I wanted.

Yes, I have screwed up many times. If I follow procedure, it usually works out ok.

Jim

[boinger]

Yep I corrected my mistake on the second baffle for the depth. But on that one my router bit came loose mid routing and cut a bit too deep.

I did do that procedure but I think I didn't measure the depth correctly so when I tried to fit the driver half of the rim was above the baffle.

[Steve Manning]

You can cut yourself a template out of a piece of scrap with the hole the same diameter as the recess your trying to make deeper. Attach the template to the baffle with carpet tape and then use a pattern bit and cut the depth to what you need. Bit looks like this, https://www.amazon.com/Freud-Bearing...rim+router+bit

[Bear]

I don't think the rabbit bit can cut deep enough. I think the woofer section needs a 1.5in counter sink. Not finding a rabbit bit that will cut that deep.

I hadn't realized the RS225 had that wide of a shelf -- 0.5" or 12mm works for a lot of larger woofers. Steve has a good idea of creating a template, but you are still basically creating scrap. Depending upon where you are in the glue-up process, you could also try to step into the cut. Use a smaller diameter cut (larger bearing) on a rabbeting bit to cut a secondary shelf on which to run the bit. This basically gets you a maximum of a half-inch support for the woofer frame, and that may be pushing it with the RS225 in MDF.

EDIT: Depending upon how large your through-hole is, this bit will get you pretty close. With the 3/8" bearing, it should do a 3/4" rabbet. Of course, they make you buy the bearing set separately.
https://www.amazon.com/Whiteside-Router-Bits-1959-Diameter/dp/B0012JEVZI



Woodpecker's sells it as a kit (the "deep" version):

https://www.woodpeck.com/routing/router-bits/rabbeting/whiteside-rabbeting-bits-and-sets.html

[roadrune]

Here, a little down on the page you can see how its done:

http://www.troelsgravesen.dk/tips.htm

[boinger]

Some more progress.

Going to try to fix the baffle soon.











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[Jim Holtz]

Looking good! :T

Jim

[boinger]

Question about the foam do apply it everywhere except the baffle and bracing?

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[Jim Holtz]

Question about the foam do apply it everywhere except the baffle and bracing?

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The purpose of the foam is to eliminate reflection of the rear sound wave that might bounce into the back of the driver. So with that thought in mind. Place foam where ever you can see that could be a reflection point while looking through the front baffle driver cutout. Hold the foam back from the inner front baffle about 1 1/2" - 2". I'd suggest you mount the crossover boards on the lower brace behind the lower woofer. Don't block the brace cut outs so air can move freely from the top of the cabinet to the port. BTW, foam in the bottom below the brace isn't necessary.

When you build the top module, it has different requirements.

HTH

Jim

[boinger]

I just realized we made a mistake. On the speaker I glued up.

In the lower shelf brace I put the narrow brace towards the back instead of the front. Will that make a big difference or do I have to rebuild the box?

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[Jim Holtz]

I just realized we made a mistake. On the speaker I glued up.

In the lower shelf brace I put the narrow brace towards the back instead of the front. Will that make a big difference or do I have to rebuild the box?

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The vertical brace was offset a bit to give more clearance for the inner port flare. Check to make sure it clears and adjust as necessary. This isn't a big deal but may require a little hand work with a rasp or grinding a bit off the flare to make it fit properly. It won't hurt bass performance.

BTW, don't change the length of the port.

Jim

[boinger]

The vertical brace was offset a bit to give more clearance for the inner port flare. Check to make sure it clears and adjust as necessary. This isn't a big deal but may require a little hand work with a rasp or grinding a bit off the flare to make it fit properly. It won't hurt bass performance.

BTW, don't change the length of the port.

Jim

Oh okay,

I did a test fit just wanted to let you know the flare comes out on the other side of the brace luckily.

So no modifications needed.

Just wanted to let you know in case it happens to someone else for future reference.

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[boinger]

Second box built.

Had a question on the bracing I can see a headline gap. Will this make a difference? Should I do for in the gap?









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[Jim Holtz]

I would just squeeze glue into the gap and run a bead around where the brace meets the side panel. It'll be fine.

Jim

[5th element]

I would just squeeze glue into the gap and run a bead around where the brace meets the side panel. It'll be fine.

Jim

In fact having a small gap between the brace and the side walls, then filling the gap with a stiff rubber compound/soft set glue is what KEF recommends!

[boinger]

Good to know did just that.

Few more pics last update till 2nd. Going out of town so won't be able to work on them.



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[Bear]

The practice has probably been relegated into the realm of witchcraft and superstition, but I almost always put a bead of silicone caulk around any areas where I think that I may have an air leak of consequence (esp. where the port interfaces with the baffle).

[Dave Bullet]

A small tip - the bracing (unless specifically called for) could benefit from a centre or slighltly offset span so that the centre of the panels "push / pull" against the brace. Having a big hole in the centre doesn't provide as much rigidity to the opposing panels. Whether this is audible, I don't know. Looking good and looking forward to completion :-)

[Ray_D]

Braces are totally ineffective

A small tip - the bracing (unless specifically called for) could benefit from a centre or slighltly offset span so that the centre of the panels "push / pull" against the brace. Having a big hole in the centre doesn't provide as much rigidity to the opposing panels. Whether this is audible, I don't know. Looking good and looking forward to completion :-)

I agree with Dave. These braces have much too large holes. If you spanned them across the middle with some 1x2 hardwood, one on top and the one at right angles on the bottom of the braces, they will be much stiffer.

[wkhanna]

not sure how much more effective having the center spar would be in total scheme, but it certainly would not hurt.

of more concern to me is the spacing between the braces.
the braces help significantly to damp (lower) the panel resonance.
but using equal spacing means the damping is at the same frequency.

by using non-symmetrical spacing you help to cancel out panel resonance across wider range, i would think......????

jmho ymmv

[Jim Holtz]

OK, guys, let's go back to basics. The purpose of bracing is to eliminate resonances from rear sound waves and to provide a firm foundation for the drivers. Other than the center span behind the lower woofer which left open for crossover mounting, there isn't a span of more than 8"-10" anywhere in the cabinet. It does not resonate. It's stiff enough it could be used as car stands.

I'd encourage you all to build the Bordeaux with bracing your way and comparison measurements to prove your point if you feel strongly about it. :W

My $0.02 worth....

Jim

[wkhanna]

OK, guys, let's go back to basics. The purpose of bracing is to eliminate resonances from rear sound waves and to provide a firm foundation for the drivers. Other than the center span behind the lower woofer which left open for crossover mounting, there isn't a span of more than 8"-10" anywhere in the cabinet. It does not resonate. It's stiff enough it could be used as car stands.

I'd encourage you all to build the Bordeaux with bracing your way and comparison measurements to prove your point if you feel strongly about it. :W

My $0.02 worth....

Jim

thanks for your input, Jim!!!

greatly appreciated...:T

[Jim Holtz]

Hi Bill,

LOL! DIY'ers often bounce between obsession and functionality. I try to stay in the middle. The nice thing is, DIY can be done "your way" so folks that have creative ideas that differ from the original design can change things as they wish.

The point I was trying to make was it works extremely well as designed and I didn't want the OP to become concerned that the cabinet is flawed. If it had any audible issues, Curt would have sent me home with orders to do it over. He's a tough project manager and wants it perfect. 8O

Peace to all....

Jim

[wkhanna]

agreed!
the OP's cabinet is well constructed, inho.

my comment was intended to be OT relative to his project, just making a generalized comment.
& as our Maestro, the fine Dr Marsh was oft to say.....

"all generalizations are false, including this one".... lol....

regarding panel resonance, keeping the un-braced square inch surfaces divided in to unequal sections with each as small as possible is just one of the many OCD things one can do with their DIY design & construction.....

[boinger]

You wouldn't happen to have a picture of the crossover mounted? Where exactly? The lower brace seems narrow.

[Jim Holtz]

You wouldn't happen to have a picture of the crossover mounted? Where exactly? The lower brace seems narrow.

I'd suggest the crossover boards be no wider than 7" to allow access after the speaker is built if necessary. You have about 15" of depth to work with which should be plenty of room to attach the crossover board(s). Remind me, did you get assembled crossovers from Meniscus? If you did, you should have separate tweeter, mid and woofer crossovers and there should be ton's of room to mount them on the lower brace behind the lower woofer.

Sorry, I didn't take any pictures of this one. You might do a search for one of the other Bordeaux builds and see what you can find for pictures.

Jim

[boinger]

I saw another build with them mounted in basicly the middle of the cabinet. Where there was no bracing on the side wall. Is that the correct spot?

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[Jim Holtz]

I saw another build with them mounted in basicly the middle of the cabinet. Where there was no bracing on the side wall. Is that the correct spot?

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The lower brace is below the bottom woofer and I left it open specifically so the crossover could be mounted in that area. It allows the wiring from the top cabinet (mid & tweeter) to easily reach the crossover boards and the wiring that connects to the crossover boards from the binding post to also be easily connected. I prefer to mount the crossover near the back of the cabinet and away from the back of the driver if possible. The cabinet depth works well in that regard.

HTH

Jim

[Bear]

Some folks need to spend some time with the Sagulator before declaring bracing to be worthless. :-) (the "edging strip" section is the relevant part...)

https://www.woodbin.com/calcs/sagulator/

[Jim Holtz]

Some folks need to spend some time with the Sagulator before declaring bracing to be worthless. :-) (the "edging strip" section is the relevant part...)

https://www.woodbin.com/calcs/sagulator/

:T Thanks Bear!

Jim

[boinger]

Do you all make the front baffle removable? Or do you just glue it together?

[Jim Holtz]

Do you all make the front baffle removable? Or do you just glue it together?

Yes, I do glue the inner and outer front individually during assembly but you can do it either way. I prefer to assemble the cabinet up to and including the inner front baffle and then assemble the outer front last. I usually over cut the outer front baffle slightly so I can use a flush trim bit in my router and get an exact fit. On these, I followed up with a 3/4" round over on the vertical front edges.

The CAD drawing and included pictures should pretty much be self explanatory.

HTH

Jim

[boinger]

I Don't Have A 3/4" round over bit could I do a 45 degree chamfer? for the inside baffle?

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[Jim Holtz]

I Don't Have A 3/4" round over bit could I do a 45 degree chamfer? for the inside baffle?

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Yes. The 3/4" roundover is smoother but a 45 degree bit will work. However, you do need to also bevel or roundover the front baffle vertical edges, both bass and top cabinet modules. A 3/4" roundover makes it much easier to make them match.

Jim

[boinger]

I have a 1/2" round over bit for the outer cabinet will that work?

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[Jim Holtz]

I have a 1/2" round over bit for the outer cabinet will that work?

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Sure, that would be fine. If you plan on veneering the cabinet, that might be a little hard to get around without cracking the veneer.

Jim