OK, but this chamber ideally needs to be well stuffed to keep it from 'drumming', so not a good place to put electronics.
Also, how do you plan to attach the glass? It's nowhere near heavy enough to be self damping.
Right the vertical brace is designed such that with a rubber or similar shim will provide a slight pressure to better couple the driver to the baffle and cab in general.
Hole patterns should be random with different diameters, removing as much material as practical, which is around 80% if the braces are made from 3/4" marine grade, BB or similar plywood and ~50% if 3/4" MDF.
That said, those drawings are for 'flat pack' kits, so as long as the braces are vertically oriented there's no need to add the holes. Indeed, the extra weight is desirable since mass loading a cab to 'anchor' it is a worthwhile goal. An extreme test example that proves that contrary to popular belief, even very heavy cabs require enough added weight proportionate to it: Who has actually done the A7 Kitty Litter Bass Horn bracing.
All that said, not much enjoying woodworking combined with not having much in the way of the appropriate power tools for most of my building 'career' and not willing to spend much time on each, I used closet rod dowels and whatever scrap I had laying around or picked up at the curb, etc., to make braces, driver mass loading and motor cradles, all tied together to all six sides to keep it from 'breathing'. This cab shows the driver mass loading scheme I mostly used:
6moons audio reviews: Ocellia Calliope 0.21 Twin Signature
A cab I designed with an elaborate motor support/bracing/mass loading scheme was for Jay Fisher, an avid DIYer I had done several other designs for and only for publishing on the forums, was actually for a ezine article, where he claimed it his design, though included some of my correspondence, all without my knowledge: 6moons audio reviews: Stephæn's Altec 604 Dream Speaker
Vent bracing is ideally required when a high aspect ratio same as a cab, so tying your long ones to the cab is a good plan and contrary to popular belief, it being an open pipe resonator [think 'plucked string'] it should be offset from the inner end at some odd harmonic, length x 1/5, 1/3, 2/5 is close enough.
Anyway, you 'catch my drift', so make it as fancy, inventive or as 'down n' dirty' as you like or none at all as most do with small cabs.
GM
Also, how do you plan to attach the glass? It's nowhere near heavy enough to be self damping.
Right the vertical brace is designed such that with a rubber or similar shim will provide a slight pressure to better couple the driver to the baffle and cab in general.
Hole patterns should be random with different diameters, removing as much material as practical, which is around 80% if the braces are made from 3/4" marine grade, BB or similar plywood and ~50% if 3/4" MDF.
That said, those drawings are for 'flat pack' kits, so as long as the braces are vertically oriented there's no need to add the holes. Indeed, the extra weight is desirable since mass loading a cab to 'anchor' it is a worthwhile goal. An extreme test example that proves that contrary to popular belief, even very heavy cabs require enough added weight proportionate to it: Who has actually done the A7 Kitty Litter Bass Horn bracing.
All that said, not much enjoying woodworking combined with not having much in the way of the appropriate power tools for most of my building 'career' and not willing to spend much time on each, I used closet rod dowels and whatever scrap I had laying around or picked up at the curb, etc., to make braces, driver mass loading and motor cradles, all tied together to all six sides to keep it from 'breathing'. This cab shows the driver mass loading scheme I mostly used:
6moons audio reviews: Ocellia Calliope 0.21 Twin Signature
A cab I designed with an elaborate motor support/bracing/mass loading scheme was for Jay Fisher, an avid DIYer I had done several other designs for and only for publishing on the forums, was actually for a ezine article, where he claimed it his design, though included some of my correspondence, all without my knowledge: 6moons audio reviews: Stephæn's Altec 604 Dream Speaker
Vent bracing is ideally required when a high aspect ratio same as a cab, so tying your long ones to the cab is a good plan and contrary to popular belief, it being an open pipe resonator [think 'plucked string'] it should be offset from the inner end at some odd harmonic, length x 1/5, 1/3, 2/5 is close enough.
Anyway, you 'catch my drift', so make it as fancy, inventive or as 'down n' dirty' as you like or none at all as most do with small cabs.
GM
GM, you definitely have me on the same wavelength. 
Last night I dreamt about this project. Of course the men in the little white coats will tell you that you always dream about what's on your mind just before night, night.
Although you had not yet mentioned it, I could not help but think without a strip of insulator material between the magnet and the brace, it would vibrate horribly. In my dream I used dense rubber weather stripping.
Regarding the port tubes, I couldn't help but think they to would vibrate excessively being unsupported. That was were I was going with the tube damping question. At that time thinking about lightly stuffing.
So in my dream I crafted a brace from 3/4" MDF, cutting holes for the tube ends to fit into tight. Knowing that the tubes are supposed vibrate harmonically, this then made me think of how I tune my acoustic guitar. (via Harmonic tuning).
I envisioned the port tubes vibrating in perfect harmonics, like a guitar string, anchored at both ends. lol.
Regarding the upper chamber design ideas.
I know not what I'm doing, this being my first project. And make many assumptions.
So your input is greatly appreciated.
The concept really began with the Heil AMT. It's massive forged metal cage, encapsulating the magnets. Then the Focal, when it arrived. The cone pattern they provided looks to me like Granite or maybe Marble. These two mounted on a black baffle appeal to me. The cab sides will be laminated with some wood grain I've not decided yet. I like the VViViV product. Although I had originally considered real hardwood for the sides. I abandoned that Idea mostly assuming not a good idea to mix wood materials.
I had not planned to attach the glass. Just allow it to sit atop the top brace and 1/4" side groves. Didn't think the upper chamber, not being a part of the woofer "Enclosure", would need any damping. Although I had planned to adhere some felt or some such material to the bottom of the glass and potentially, if needed, some damping panel directly behind the AMT.
So that then seemed like a good place for the crossovers.
One concern I still needed to address was proper distance from the AMT to the inductors.
I'll go back to the board and incorporate the lower chamber driver/vent braces. post them up for review.
I am trying to keep this a simple project, but want it to be right.
Mechanically, electronically and most of all acoustically.
Thanks so much.
Last night I dreamt about this project. Of course the men in the little white coats will tell you that you always dream about what's on your mind just before night, night.
Although you had not yet mentioned it, I could not help but think without a strip of insulator material between the magnet and the brace, it would vibrate horribly. In my dream I used dense rubber weather stripping.
Regarding the port tubes, I couldn't help but think they to would vibrate excessively being unsupported. That was were I was going with the tube damping question. At that time thinking about lightly stuffing.
So in my dream I crafted a brace from 3/4" MDF, cutting holes for the tube ends to fit into tight. Knowing that the tubes are supposed vibrate harmonically, this then made me think of how I tune my acoustic guitar. (via Harmonic tuning).
I envisioned the port tubes vibrating in perfect harmonics, like a guitar string, anchored at both ends. lol.Regarding the upper chamber design ideas.
I know not what I'm doing, this being my first project. And make many assumptions.
So your input is greatly appreciated.
The concept really began with the Heil AMT. It's massive forged metal cage, encapsulating the magnets. Then the Focal, when it arrived. The cone pattern they provided looks to me like Granite or maybe Marble. These two mounted on a black baffle appeal to me. The cab sides will be laminated with some wood grain I've not decided yet. I like the VViViV product. Although I had originally considered real hardwood for the sides. I abandoned that Idea mostly assuming not a good idea to mix wood materials.
I had not planned to attach the glass. Just allow it to sit atop the top brace and 1/4" side groves. Didn't think the upper chamber, not being a part of the woofer "Enclosure", would need any damping. Although I had planned to adhere some felt or some such material to the bottom of the glass and potentially, if needed, some damping panel directly behind the AMT.
So that then seemed like a good place for the crossovers.
One concern I still needed to address was proper distance from the AMT to the inductors.
I'll go back to the board and incorporate the lower chamber driver/vent braces. post them up for review.
I am trying to keep this a simple project, but want it to be right.
Mechanically, electronically and most of all acoustically.
Thanks so much.
Last edited:
Looking at this horizontal driver brace...
http://p10hifi.net/tlinespeakers/FAL/box-plans/microFonken-0v9-map.pdf
Would that work?
So many questions.
http://p10hifi.net/tlinespeakers/FAL/box-plans/microFonken-0v9-map.pdf
Would that work?
So many questions.
Here's some mod sketches.
I really like how the vertical braces tie this all together.
I did a horizontal version of the driver support, but I like the vert better.
Modified my bottom brace to align with the vert mods.
It looks like a Tike Head.
One thing to note on the cab drawing is I have glue blocks layer off.
They will be screwed and glued to the sides, base and wherever needed.
More comments welcome.
I really like how the vertical braces tie this all together.
I did a horizontal version of the driver support, but I like the vert better.
Modified my bottom brace to align with the vert mods.
It looks like a Tike Head.
One thing to note on the cab drawing is I have glue blocks layer off.
They will be screwed and glued to the sides, base and wherever needed.
More comments welcome.
Attachments
Ideally, the baffle is wide enough to offset the driver in a golden or acoustic ratio [mirror image speakers], ergo ditto the vertical brace along with any other vertical or horizontal braces to average out panel resonances, but yours are too small, so must be centered to be centered on the driver.
I used cheap 1.25" dia. Southern Pine closet rod for large drivers and either an adjustable screw brace with threaded rod, etc., or wood strip clamps like shown holding the tweeters in that same cab and the cutout motor brace for drivers with a rear vent.
GM
Great!
So if there is nothing more to recommend for the lower chamber, there is still your comments regarding the upper section and drumming.
Much the same that some folks remove the grills or don't have them at all.
If I were to remove the glass covers from the cab during play, would this thereby eliminate any drumming effects?
Having the cover removable was always the plan. mostly to access the crossovers.
But now in considering undesirable effects.
BTW, I have looked at some of your projects.
My cab is quite small compared to your works.
However, in order to alleviate speaker envy, I prefer to think of them as "Fun Size".
So if there is nothing more to recommend for the lower chamber, there is still your comments regarding the upper section and drumming.
Much the same that some folks remove the grills or don't have them at all.
If I were to remove the glass covers from the cab during play, would this thereby eliminate any drumming effects?
Having the cover removable was always the plan. mostly to access the crossovers.
But now in considering undesirable effects.
BTW, I have looked at some of your projects.
My cab is quite small compared to your works.
However, in order to alleviate speaker envy, I prefer to think of them as "Fun Size".
Well, you would change them from 1/2 WL harmonics [open cylinder] to the more powerful 1/4 WL [closed cylinder], though both will be pretty high up in BW due to its depth [cylinder length] being so short.
Bottom line is neither is a viable option for me without sufficient damping, so no place for an XO. Like you though, I prefer easy access to XOs, but put them on the rear in a cooling 'chimney' cum terminal pad. http://hyperphysics.phy-astr.gsu.edu/hbase/waves/opecol.html#c1
Yeah, I've designed/built tiny cabs [~0.25 ft^3 net max] for others, though the smallest I can remember building for myself are a pair of similar size just turned 47 yr old garage speakers loaded with Sony 6.5" two way mobile audio systems. Everything else are well over a ft^3 even for small drivers [4" min] due to their specs and all being some 'flavor' of TL/horn.
GM
Bottom line is neither is a viable option for me without sufficient damping, so no place for an XO. Like you though, I prefer easy access to XOs, but put them on the rear in a cooling 'chimney' cum terminal pad. http://hyperphysics.phy-astr.gsu.edu/hbase/waves/opecol.html#c1
Yeah, I've designed/built tiny cabs [~0.25 ft^3 net max] for others, though the smallest I can remember building for myself are a pair of similar size just turned 47 yr old garage speakers loaded with Sony 6.5" two way mobile audio systems. Everything else are well over a ft^3 even for small drivers [4" min] due to their specs and all being some 'flavor' of TL/horn.
GM
Sorry GM, you lost me on that one.
Seems like you are discussing the port tube harmonics.
I think I'm going to leave the top open for now until measurements can be taken.
Then decide whether or not to close and damp the upper chamber, and move the Crossovers outside the cab or not.
I'll need to know how the Heil AMT is going to sound like before deciding.
This shouldn't effect the lower chamber tuning I assume, as it will be closed and sealed.
Thank you for all your contributions. They have truly improved my design.
Seems like you are discussing the port tube harmonics.
I think I'm going to leave the top open for now until measurements can be taken.
Then decide whether or not to close and damp the upper chamber, and move the Crossovers outside the cab or not.
I'll need to know how the Heil AMT is going to sound like before deciding.
This shouldn't effect the lower chamber tuning I assume, as it will be closed and sealed.
Thank you for all your contributions. They have truly improved my design.
You're welcome!
True, but then a sealed box has the same harmonic structure as an open pipe/box vent, though in retrospect I should have related it to a room's 1/2 WL modal structure since it has them in three planes.
With the lid off, it's a low aspect ratio [short] closed pipe, so has 1/2 WL eigenmodes in two planes and 1/4 WL eigenmodes in the other.
Anyway, it will be interesting to 'see' how audible they may be.
GM
True, but then a sealed box has the same harmonic structure as an open pipe/box vent, though in retrospect I should have related it to a room's 1/2 WL modal structure since it has them in three planes.
With the lid off, it's a low aspect ratio [short] closed pipe, so has 1/2 WL eigenmodes in two planes and 1/4 WL eigenmodes in the other.
Anyway, it will be interesting to 'see' how audible they may be.
GM
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