Hello johnferrier, I think the main reason you don't see more speaker cabinets made from metal is due to the necessity of having proper machine tools, and proper documentation and dimensional tolerancing. Especially for DIY stuff. Otherwise, there have been cabinets made from metal over the years. The Realistic Minimus-7 is one that comes to mind. Many others of similar design. I have a pair of cabinets from Japan (forget the maker) that were designed of metal, with a tweeter in the center and a 4" driver on one side and a 4" passive on the other.
Peace,
Dave
P.S. Gotta get a driver setup into those cabinets.
Peace,
Dave
P.S. Gotta get a driver setup into those cabinets.
I think Dave hit the nail on the head. Without the skill and high tolerance tools, metal/alloy is allot of work and expensive.
Having said that, if you design something simple that translates to minimal machining on a CNC rig you can get some panels made by a pro workshop to very high tolerances/standard.
Alloy is probably the way to go, think maybe 4000 series which in a 10mm panel for a small enclosure will be super strong and reasonable cheap(ish).
Again, its best to design, check, redesign, check, take a break then redesign with metal jobs, 0.25mm out and she's just flash looking scrap metal.
Dean
Having said that, if you design something simple that translates to minimal machining on a CNC rig you can get some panels made by a pro workshop to very high tolerances/standard.
Alloy is probably the way to go, think maybe 4000 series which in a 10mm panel for a small enclosure will be super strong and reasonable cheap(ish).
Again, its best to design, check, redesign, check, take a break then redesign with metal jobs, 0.25mm out and she's just flash looking scrap metal.
Dean
This is quite interesting. Thanks for the thoughts guys!
The Magico Q5
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The Magico Q5
An externally hosted image should be here but it was not working when we last tested it.
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Can I ask, whats the advantage if any?
I have all the tools to work with metal and make something like the above but why would I? Other than the difficulty and a lot more investment in time what would be the benefit.
I wonder how thick the sides are on the speakers in the picture? Surely steel/aluminium would transmit higher freqs a lot more than timber does.
I really don't know but steel just seems like it would give issues.
I have all the tools to work with metal and make something like the above but why would I? Other than the difficulty and a lot more investment in time what would be the benefit.
I wonder how thick the sides are on the speakers in the picture? Surely steel/aluminium would transmit higher freqs a lot more than timber does.
I really don't know but steel just seems like it would give issues.
I just picked up two pieces of aluminium, each 10mm thick. One was about 500mm long x 125 and the other ~400mm long by 250mm. Compared to a similar sized piece of wood the aluminium seemed to resonate worse after hitting it.. Perhaps not scientific but if I didnt know anything else I would use timber based on that test.
Hello jason, I understand why your observations may deter you, but there's more to it than that. Notice that there is extensive bracing in various directions, this stiffens the baffle and other panels. This stiffening reduces the apparent surface area that can resonate, thus moving the resonant frequency higher. Now that you have the resonant frequency of the cabinet moved high enough, it is out of the range where there is large enough amounts of energy to stimulate resonance in the cabinet.
All materials have a resonance, that's based upon material composition and the size and shape of the material. The trick is to get the resonance out of the region where it's likely to be excited by the energy coming from the drivers. Since bass is the real issue here, get the resonance high enough and it is much easier to control. You can reduce or eliminate higher frequency resonance with other techniques.
Peace,
Dave
All materials have a resonance, that's based upon material composition and the size and shape of the material. The trick is to get the resonance out of the region where it's likely to be excited by the energy coming from the drivers. Since bass is the real issue here, get the resonance high enough and it is much easier to control. You can reduce or eliminate higher frequency resonance with other techniques.
Peace,
Dave
These sorts of issues a not problems for what I normally use aluminium for.
Jason, I think your observation and reasoning are perfectly valid, it just illustrates the resonance and low damping ability of metal.... Yes there may be some ways to control metal resonance frequency, but why the hell bother when you can use a cheaper, and easier material to work with ???? (or why make it simple, when you can make it a whole lot more complicated?) The effort and cost of doing that strengthening work would have been much better put making a perfectly designed wood enclosure
There no advantage to working with Metal in a cabinet enclosure, and a lot of disadvantages...
There no advantage to working with Metal in a cabinet enclosure, and a lot of disadvantages...
How about a cast iron enclosure? Gray iron has some natural dampening properties, 10x steel.
Of course I might be one of the few who could do this, and the motivation may never authentically represent the pursuit of good music reproduction rather than novelty or fetish, but it could be a pretty wild diy build and raw castings could be supplied even if not cheap for diy build to others.
I think I'll do this someday just for kicks. I'm not sure which design is best suited to this. The geometries best suited for casting are sometimes counter intuitive, weight is a factor, some shapes could be cast hollow, but then hard to get inside.
Of course I might be one of the few who could do this, and the motivation may never authentically represent the pursuit of good music reproduction rather than novelty or fetish, but it could be a pretty wild diy build and raw castings could be supplied even if not cheap for diy build to others.
I think I'll do this someday just for kicks. I'm not sure which design is best suited to this. The geometries best suited for casting are sometimes counter intuitive, weight is a factor, some shapes could be cast hollow, but then hard to get inside.
Gentlemen,
I have not read this thread in great detail, but I do have a couple of comments.
1. Bell modes: A piece of metal, or anything else, it held by a single point in the middle and struck on an edge will "ring like a bell". Constrain the edges and bell modes cannot occur. Try this: Take a crystal glass, hold it by the stem and strike the rim. The glass rings. Now press the glass rim firmly against a hard surface and strike the side of the glass. The glass goes "tick". No ringing. Speaker cabinets are built with panel edges constrained. The panels cannot ring in bell mode. (BTW, stamped frame drivers work the same way. Although they may ring like a bell loose in hand, once mounted they cannot ring in bell mode.)
2. You cannot stop a panel from resonating at some frequency . What is important is the frequency of the resonance. As long as the resonant frequency is higher than the operating bandwidth of the cabinet, the panel will not resonate. The main argument for plywood vs MDF is the resonant frequency is higher. Metal will raise the resonant frequency even higher.
3. You will get pressure induced deformation of the cabinet walls, the amount depending on the internal pressure in the cabinet. Bracing helps. Bracing also makes the resonant frequencies of the panels higher. As long as the panel thickness and bracing scheme is adequate, no problem.
4. Metal should be an ideal material for speaker cabinets. So why don't we see more metal cabinets? Adequate thickness metal is expensive, and metal fabrication is beyond the means of the average DIY'er.
Bob
I have not read this thread in great detail, but I do have a couple of comments.
1. Bell modes: A piece of metal, or anything else, it held by a single point in the middle and struck on an edge will "ring like a bell". Constrain the edges and bell modes cannot occur. Try this: Take a crystal glass, hold it by the stem and strike the rim. The glass rings. Now press the glass rim firmly against a hard surface and strike the side of the glass. The glass goes "tick". No ringing. Speaker cabinets are built with panel edges constrained. The panels cannot ring in bell mode. (BTW, stamped frame drivers work the same way. Although they may ring like a bell loose in hand, once mounted they cannot ring in bell mode.)
2. You cannot stop a panel from resonating at some frequency . What is important is the frequency of the resonance. As long as the resonant frequency is higher than the operating bandwidth of the cabinet, the panel will not resonate. The main argument for plywood vs MDF is the resonant frequency is higher. Metal will raise the resonant frequency even higher.
3. You will get pressure induced deformation of the cabinet walls, the amount depending on the internal pressure in the cabinet. Bracing helps. Bracing also makes the resonant frequencies of the panels higher. As long as the panel thickness and bracing scheme is adequate, no problem.
4. Metal should be an ideal material for speaker cabinets. So why don't we see more metal cabinets? Adequate thickness metal is expensive, and metal fabrication is beyond the means of the average DIY'er.
Bob
I have access to a foundry, if anyone comes up with a reasonable idea i'll try it out. Aluminum would be the easiest material to cast, brass and bronze are far too expensive right now. iron would be heavy... very, although i can cast iron up to 180lbs which is about 3cf solid in a single mold.