Bigger wall thickness is going to help, the bolts applying the vertical pressure too! I just had to mention this to you, it bothered me 
. You'll have to be the one telling us how successful this construction is!
Compared to that picture I have a rigid outer shell on my speakers (epoxy + matt) and glued automotive damping (butyl plus thin alu) on the inner seams.
I'm glad you like SketchUp. It's probably all you need for making a design like this. I see many on here using it.
You could hand-cut the templates. The router bit cutting size and it's roller bearing on top following the template determines the accuracy. The beauty is all slices you cut will all be the same size. I just figured an aluminium template would last me longer. But I have to admit, I nicked one of my aluminium templates early on when a bearing came loose while routing. It made the job afterwards more involving because I had to prevent following that nick by reversing the template for a last partial cut along the template's other side.
The same thing happened with the baffle cuts, where I had many exploding roller bearings. But by then I was smart enough to find out I could fix the nick in the template by hammering down a hole punch nearby and filing it back into shape. You live, you learn
I do hope you didn't miss my comment on Mass loaded vinyl probably not being the best material for that gasket? I used rings of mass loaded vinyl on the ends of my threaded rods, figuring they would act as a spring load. The mass loaded vinyl just compressed and never veered back into the original shape. You'd need some kind of rubber I suppose...
. You'll have to be the one telling us how successful this construction is!Compared to that picture I have a rigid outer shell on my speakers (epoxy + matt) and glued automotive damping (butyl plus thin alu) on the inner seams.
I'm glad you like SketchUp. It's probably all you need for making a design like this. I see many on here using it.
You could hand-cut the templates. The router bit cutting size and it's roller bearing on top following the template determines the accuracy. The beauty is all slices you cut will all be the same size. I just figured an aluminium template would last me longer. But I have to admit, I nicked one of my aluminium templates early on when a bearing came loose while routing. It made the job afterwards more involving because I had to prevent following that nick by reversing the template for a last partial cut along the template's other side.
The same thing happened with the baffle cuts, where I had many exploding roller bearings. But by then I was smart enough to find out I could fix the nick in the template by hammering down a hole punch nearby and filing it back into shape. You live, you learn
I do hope you didn't miss my comment on Mass loaded vinyl probably not being the best material for that gasket? I used rings of mass loaded vinyl on the ends of my threaded rods, figuring they would act as a spring load. The mass loaded vinyl just compressed and never veered back into the original shape. You'd need some kind of rubber I suppose...
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Would this be good for the template, 1/4" 6061 T6 aluminum:
https://www.onlinemetals.com/merchant.cfm?pid=1248&step=4&showunits=inches&id=76&top_cat=60#
Is this overkill for the template? Sounds like it might be worth investing in the high grade aluminum. Is 1/4" thick enough, seems like it should be.
For the baffle I'm leaning toward 3/4" Corian that I've used before in other projects, however the aluminum is really tempting. Perhaps I'll start with the Corian and consider aluminum for a future upgrade.
Thanks again Ronald. Drinks are on me next time I'm in the Netherlands!
https://www.onlinemetals.com/merchant.cfm?pid=1248&step=4&showunits=inches&id=76&top_cat=60#
Is this overkill for the template? Sounds like it might be worth investing in the high grade aluminum. Is 1/4" thick enough, seems like it should be.
For the baffle I'm leaning toward 3/4" Corian that I've used before in other projects, however the aluminum is really tempting. Perhaps I'll start with the Corian and consider aluminum for a future upgrade.
Thanks again Ronald. Drinks are on me next time I'm in the Netherlands!
It would probably be a little overkill, that's top spec aluminium and it will do the job, no doubt. I used 8 mm thickness, but I just figured that's what it would take when I ordered it to be water yet cut.
1/4 inch would be about 6 mm and would do it. Easier to cut anyway.
I used scrap pieces of my 6 mm outer baffle as a template for the chamfering on the inside. It worked fine. As long as the bearing can follow the template you're ok. You could bolt it to the rough cut wood with some spacer rings in between. I do advice to cut the wood roughly in shape prior to routing. Less to cut with the router bit makes it a lot easier.
To make the rough cuts I just laid the template on the wood and followed it with a pencil inside a spacer ring about 4 mm wide.
Excuse the picture quality and materials (lol) just what I had on hand on my desk.
I used a jig saw to do the rough cuts, both on the birch ply as well as the aluminium baffles.
I have zero experience with Corian though. For use as baffle material I would want to know if it would need damping.
Basically my aluminium baffles are pressed to the enclosure with neoprene damping. Sorbothane would be even better.
The bolts have a rubber ring between them and the aluminium baffle, I did notice an improvement on my impedance plots
with those rubber rings added to the mix. So in a way it's a floating baffle between damping materials.
1/4 inch would be about 6 mm and would do it. Easier to cut anyway.
I used scrap pieces of my 6 mm outer baffle as a template for the chamfering on the inside. It worked fine. As long as the bearing can follow the template you're ok. You could bolt it to the rough cut wood with some spacer rings in between. I do advice to cut the wood roughly in shape prior to routing. Less to cut with the router bit makes it a lot easier.
To make the rough cuts I just laid the template on the wood and followed it with a pencil inside a spacer ring about 4 mm wide.
Excuse the picture quality and materials (lol) just what I had on hand on my desk.
I used a jig saw to do the rough cuts, both on the birch ply as well as the aluminium baffles.
I have zero experience with Corian though. For use as baffle material I would want to know if it would need damping.
Basically my aluminium baffles are pressed to the enclosure with neoprene damping. Sorbothane would be even better.
The bolts have a rubber ring between them and the aluminium baffle, I did notice an improvement on my impedance plots
with those rubber rings added to the mix. So in a way it's a floating baffle between damping materials.
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Ronald, wasn't one of the difficulties you ran into cutting all that Al was due to the use of a single speed router? That was insane and in the catagory of things to never do
JR, when you spec your carbide router bits look for at least a C3 (very good) if not a C4 grade (highest quality) bit. The lower the number the duller they get, but are still always way so much better than HS Steel.
JR, when you spec your carbide router bits look for at least a C3 (very good) if not a C4 grade (highest quality) bit. The lower the number the duller they get, but are still always way so much better than HS Steel.
Thanks Greebster. I will not skimp on the router bits. I've been looking at Whiteside and Freud bits. This one looks terrific, but is crazy expensive:
https://www.amazon.com/Whiteside-Model-UDFT9112-Spiral-Flush/dp/B009102D1Y
I have Porter-Cable 1 3/4 hp and 3 1/2 hp routers. The big one is a monster, mounted in a good table. These should work quite well. I also have a nice Delta table saw and a terrific Bosch compound miter saw with an 8' feed table. Also a decent Delta drill press and excellent Bosch hand drills. The only thing I really need is a new jig saw and I will be all set. I want to have everything just right before the first cut. Most of my work has been large scale cabinets. This type of work requires a bit more precision than I normally need. I'll post some pictures of my cabinets later this week.
Thanks for the advice!
https://www.amazon.com/Whiteside-Model-UDFT9112-Spiral-Flush/dp/B009102D1Y
I have Porter-Cable 1 3/4 hp and 3 1/2 hp routers. The big one is a monster, mounted in a good table. These should work quite well. I also have a nice Delta table saw and a terrific Bosch compound miter saw with an 8' feed table. Also a decent Delta drill press and excellent Bosch hand drills. The only thing I really need is a new jig saw and I will be all set. I want to have everything just right before the first cut. Most of my work has been large scale cabinets. This type of work requires a bit more precision than I normally need. I'll post some pictures of my cabinets later this week.
Thanks for the advice!
True... after the first router crapped out on me I focussed on getting a powerful router at a decent price and settled for a single speed monster.
Even with the ply I had to move pretty fast not to burn the wood.
At that time I didn't expect to cut aluminium though...
Quite a bit more expensive than my ~ € 16,00 bits
It looks like you have a nice collection of tools to get this job done. I opted for a drill stand rather than a drill press to be able to set it up for some tasks I had in mind. One thing that made my life easier was to make simple helper tools to be able to repeat all of the tasks...
Here you see the drill stand in action, something I couldn't have done as easily with a drill press.
A snapshot of the same helper tool, still mounted on one of the slices:
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All jigs are templates, but not all templates are jigs.Jigs... that was the word I was looking for
All jigs are templates, but not all templates are jigs.
Yes!
...when that router bit gets fried, the jig is up!
Even after all these years, it can be challenging to express myself in English at times...
I did have basic skills in the language but had to learn all of the technical parts, both for my automotive and speaker hobby, by reading a lot.
As a consequence, I would have a hard time explaining myself in Dutch too!
I did have basic skills in the language but had to learn all of the technical parts, both for my automotive and speaker hobby, by reading a lot.
As a consequence, I would have a hard time explaining myself in Dutch too!
I saw the note from Wesayso about me having some answers about a good material to use as a constrained layer material. I have to look into a material that would meet all the requirements. My concern with many of these ideas is that the material properties of most materials just don't work over long periods of time. They may indeed work wonderfully at first but if you go back after enough time you will find that the material has undergone what is called creep and is no longer under the same compressed condition as originally envisioned. This is a standard problem with most plastics and elastomers when they are under pressure. A plastic part will move and loose contact or a pressure seal and an elastomeric material will move or flow perpendicular to the applied force, this is commonly referred to as compression set. I would think in JRSystems application you would need to occasionally have to tighten the through bolts to keep the pressure applied between layers. I would also suspect that Wesayso would need to tighten the fasteners holding the aluminum face plates together to keep the same compression values as was originally achieved when he first built the line arrays. Now depending on the material used as the center elastomer that could take months or even years to cause this type of creep but usually it will be a shorter time frame than that. I'll think about a material that would be a good material for this type of situation that would be available in some type of sheet form.
Very interesting, good points. Perhaps there are gaskets for automotive applications designed to withstand excessive stresses.
Tightening things up periodically is also no problem. Another advantage of DIY speakers. I'd be more worried about the material drying out or deforming.
Tightening things up periodically is also no problem. Another advantage of DIY speakers. I'd be more worried about the material drying out or deforming.
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Take this with a grain of salt as they are probably pushing their own materials but the information will be informative.
Compression Set of Elastomeric Materials | Stockwell Elastomerics
www.jameswalker.biz/de/pdf_docs/148-elastomer-engineering-guide
Compression Set of Elastomeric Materials | Stockwell Elastomerics
www.jameswalker.biz/de/pdf_docs/148-elastomer-engineering-guide
Alrighty, I have dug deep into SketchUp (thank you Ronald for that recommendation!) and I have my first design exercise to share.
This is the translam design that I've mentioned, built in four sections with a 1/8" neoprene gasket between the layers. There will be 6 1/4" rods bolting it all together (maybe I should do 8?) It's a pretty big speaker due to the 2" thick side walls. but I like the dimensions. Thanks to the wonderful area measurement tool, I was able to get the internal volume to .94 cu ft, just slightly off of the .95 specified for the kit. I'm still not crazy about the top piece. I want to hide the bolt heads, but include the top piece in the bolted sections. On the bottom, I can just recess the washers and nuts, but the top remains an issue.
I still need to layout the mounting for the baffle. This design will require the baffle to be screwed at a perpendicular to the plywood face which I really do not want to do. I would much rather bolt it in, but that would require a parallel back surface to the front mounting area which would require compromising my wall thickness or widening the front baffle -which I do not want to do. I'm probably going to do a 3/4" Corian for the initial baffle. Ultimately, I would love to do two aluminum layers, perhaps a 1/2" each with a gasket between, similar to Ronald's design.
Since I will ultimately move toward electronic crossover, I think I'm just going to do the crossover externally and have a pair of binding posts go directly to the drivers on each speaker..
This is fun!
This is the translam design that I've mentioned, built in four sections with a 1/8" neoprene gasket between the layers. There will be 6 1/4" rods bolting it all together (maybe I should do 8?) It's a pretty big speaker due to the 2" thick side walls. but I like the dimensions. Thanks to the wonderful area measurement tool, I was able to get the internal volume to .94 cu ft, just slightly off of the .95 specified for the kit. I'm still not crazy about the top piece. I want to hide the bolt heads, but include the top piece in the bolted sections. On the bottom, I can just recess the washers and nuts, but the top remains an issue.
I still need to layout the mounting for the baffle. This design will require the baffle to be screwed at a perpendicular to the plywood face which I really do not want to do. I would much rather bolt it in, but that would require a parallel back surface to the front mounting area which would require compromising my wall thickness or widening the front baffle -which I do not want to do. I'm probably going to do a 3/4" Corian for the initial baffle. Ultimately, I would love to do two aluminum layers, perhaps a 1/2" each with a gasket between, similar to Ronald's design.
Since I will ultimately move toward electronic crossover, I think I'm just going to do the crossover externally and have a pair of binding posts go directly to the drivers on each speaker..
This is fun!
Attachments
JRSystems,
A word of warning that neoprene most definitely shrinks over time. So beware if you are planning to make it flush with the outside of the enclosure as eventually it will pull in. You would be better off intentionally set it in a small amount as a design feature. This caused a real problem with a project I did with JBL after they discovered that the neoprene they had die cut for the front of an enclosure was shrinking back and didn't look right. Expect to need to re-tighten the compression bolts after some time. Nice look though, this has become a classic shape at this time.
Steven
A word of warning that neoprene most definitely shrinks over time. So beware if you are planning to make it flush with the outside of the enclosure as eventually it will pull in. You would be better off intentionally set it in a small amount as a design feature. This caused a real problem with a project I did with JBL after they discovered that the neoprene they had die cut for the front of an enclosure was shrinking back and didn't look right. Expect to need to re-tighten the compression bolts after some time. Nice look though, this has become a classic shape at this time.
Steven
I'd like to add that though it might look good to have the baffle sit 'inside' at the top and bottom, I'd worry about the difference in expansion rate of the enclosure and front baffle. That's why I liked the Magico Mini, that baffle is totally independent from the movement of the wooden enclosure. The wood is able to contract/expand without affecting the baffle.