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Custom Concrete Speaker Cabinets
Custom Concrete Speaker Cabinets
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Old 18th June 2017, 08:06 PM   #31
Bigun is offline Bigun  Canada
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Custom Concrete Speaker Cabinets
There are a few ideas you can find....


I quite like the 'rough' look for concrete speakers, it's a design choice of course. See image of 'Brutus' full range. Nice size too.

I like this stuff too, I'd have this in my house (it looks non-trivial to make): Concrete Audio
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Last edited by Bigun; 18th June 2017 at 08:10 PM.
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Old 18th June 2017, 08:10 PM   #32
CharlieLaub is offline CharlieLaub  United States
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Originally Posted by Bigun View Post
There are a few ideas you can find....


I quite like the 'rough' look for concrete speakers, it's a design choice of course. See image of 'Brutus' full range. Nice size too.

I like this stuff too: Concrete Audio
I think that is a photoshopped image. I don't see any fasteners (e.g. screws) in the driver on the right.

I have seen the Concrete Audio site before. They did a lot of shows up until mid 2016 and then nothing is listed after that.
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Last edited by CharlieLaub; 18th June 2017 at 08:15 PM.
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Old 18th June 2017, 10:29 PM   #33
Boden is offline Boden  Netherlands
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Well, with a 6" midwoofer it could be used as a satellite until 90 Hz or so. A carefully placed assembly of subs a la Geddes/Welti or built in subs could do the very low end. Deep bass then could finally work with instead of against the room.

For a more conventional approach such a sphere unit could be placed on top of a B&W 801 style enclosure, but preferably a bit more rounded at the angles. I do not see any immediate advantages with an up firing woofer, but might be overlooking those.
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Old 19th June 2017, 05:03 PM   #34
CharlieLaub is offline CharlieLaub  United States
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For now I think I will focus on a conventional rectangular box that the DIYer is familiar with. It will probably be provided without front and rear baffle. I am hopeful that blank MDF or similar baffles could be provided to fit front and rear that the DIYer could modify as needed for drivers, port, binding posts, etc. since this is familiar territory for most loudspeaker builders and it would allow the most flexibility in terms of what can be built with the cabs.

I exchanged a couple of emails with the terrazzo guy and he has used glass microspheres and other fillers that reduce the density of the material. We are now trying to decide what size cabinets would make sense to make. We could make two that could nest in a single shipping box/crate so that they could be shipped together if the DIYer wanted both sizes.
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Old 19th June 2017, 05:26 PM   #35
whgeiger is offline whgeiger  United States
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>snip<
I think that a sphere would have some nice acoustic properties (smooth baffle step transition). How to integrate that with a bass unit would take some thinking. I did have the idea that a sphere could be put above a large rectangular pedestal/box with a large (e.g. 15" or 18") driver firing upwards and the sphere almost nestled into it. If you keep below the frequency where you start to get interference between driver and sphere this might work well. Thoughts?
Internal standing wave modes are focused into a single set of frequencies due to the common radius of a sphere. An egg-shape will diversify these and spread acoustic energy in the back chamber over a larger, harmonically unrelated set. WHG
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Old 19th June 2017, 06:55 PM   #36
CharlieLaub is offline CharlieLaub  United States
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Internal standing wave modes are focused into a single set of frequencies due to the common radius of a sphere. An egg-shape will diversify these and spread acoustic energy in the back chamber over a larger, harmonically unrelated set. WHG
That's right. You can try to address this by modifying the interior space to include a bullet shaped object behind the magnet of the driver to redirect/reflect sound and adding stuffing or, as you mention, change the internal shape by making it a teardrop shape. Both of these approaches were used by B&W.

I was more thinking about the smooth radiation pattern of the driver-in-sphere as shown by Olson and others in the low to mid frequency "baffle step" transition region.

Anyway, something like that will be down the road a bit...
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Old 19th June 2017, 07:24 PM   #37
TNT is offline TNT  Sweden
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Concrete N... one pour. I tried to figure it out on this years Munich event but the sales guy was well trained and revealed nothing No demo which was a disappointment.

Concrete Audio

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Old 19th June 2017, 08:48 PM   #38
whgeiger is offline whgeiger  United States
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Originally Posted by CharlieLaub View Post
That's right. You can try to address this by modifying the interior space to include a bullet shaped object behind the magnet of the driver to redirect/reflect sound and adding stuffing or, as you mention, change the internal shape by making it a teardrop shape. Both of these approaches were used by B&W.

I was more thinking about the smooth radiation pattern of the driver-in-sphere as shown by Olson and others in the low to mid frequency "baffle step" transition region.

Anyway, something like that will be down the road a bit...
While not demonstrated by Olson, two spheres of differing [R] and morphed together, provide a smooth diffraction surface for both drivers of a 2-way satellite unit . WHG
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Old 19th June 2017, 11:18 PM   #39
CharlieLaub is offline CharlieLaub  United States
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While not demonstrated by Olson, two spheres of differing [R] and morphed together, provide a smooth diffraction surface for both drivers of a 2-way satellite unit . WHG
Ah, interesting. So assuming we can describe this loosely as an "egg" shape, where on the surface do you thing would the drivers best be located? On the larger round end or on the "side" with the larger driver towards the larger end and the smaller (e.g. tweeter) towards the smaller end?

One issue that comes along with any enclosure that doesn't have any flat surfaces is how to stand it up as a loudspeaker. Your "egg" or my "sphere" will roll away unless there is a stand included that cradles it or some portion of it, or there are three of four struts cast into it that can be used to stand it up on top of something... any thoughts on that?
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Old 19th June 2017, 11:48 PM   #40
planet10 is offline planet10  Canada
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I was more thinking about the smooth radiation pattern of the driver-in-sphere as shown by Olson and others in the low to mid frequency "baffle step" transition region.
Oslon only took it as far as the sphere. An eggshape or even better, The B&W shape keep the semisphere front but have a better trailing side.

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