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I had a set of Logitech X-230 speakers lying around. I always thought they had a decent sound considering the little money you have to pay for them.

So I wanted to reactivate them, but this time with a slightly modified design. I had ideas for concrete speaker housings in my head for quite some time, so I decided this would be the perfect time to give these ideas a try on the logitechs, in a way of a proof of concept.

Step 1: Designing the Speakers and Modeling the Mold Parts

As I said, i already had some ideas for the design before i started the build. One of them was a square body with rounded edges and a solid concrete top and bottom piece. Each side should look like the other, completely wrapped in black smooth foam to contrast with the rough and cold concrete top and bottom parts.

First I modeled the speakers with every detail completely in Rhino and took some renderings to visualize my intentions. For the modeling it is very important that your new enclosures have the same volume as the original ones for the speakers to sound and function properly. So I dismantled the original housings, removed the drivers and filled the enclosures with water to determine the volume I'll need for the new ones. Simply measure the volume of the water that fits in there and you're done, you could also use sand by the way.

Based on this volume I was able to define the dimensions needed for the new housing. It consists of three parts: a hollow profile with the determined volume that holds the two drivers and a solid top an bottom cap.

Since I needed the negative shape of the housing parts I used the "boolean difference" command in Rhino and got the shapes I needed for making the molds for the concrete. These were then further divided in separate parts to be milled out of styrofoam. The processing of the tool paths for the machine took place in Autodesk Fusion 360.

Step 2: Milling Out the Molds

The molds were milled out of 40mm thick styrofoam. The material allows for fast feed rates of the machine and therefore little time in making all the parts needed. But it is still rigid enough for holding the details and to be filled with concrete later on.

This step was made on my DIY shapeoko-style Desktop CNC mill.

Step 3: Preparing the Molds

For easier demolding I applied a very thin layer of grease on all surfaces that will come in contact with the concrete. Then the separate mold parts were properly aligned and put together with screws. Since they're easily removable after the concrete cured, this will also help for an trouble-free demolding.

Step 4: Pouring the Concrete

The next step was to mix the concrete to a runny texture and pouring it into the molds. Tapping on the molds helps to get most of the bubbles out. I flattened the surfaces by using a wooden stick to wipe off the excessive concrete on the top.

After the molds are poured, attention must be taken to not let the concrete dry out since it needs the water for proper hardening. So I covered the molds with a damp cloth and let the concrete cure for 2 days before i started to demold.

Step 5: Remove the Mold

This is the best part of the process. The mold came off easily and there was just a minimum amount of bubbles. All the details came out nicely and the result was accurate to size.

Step 6: Sanding Some Corners and Edges

I slightly sanded the concrete with 400 grit sandpaper for getting the parts fitting tightly together. I also applied a thin layer of clear lacquer for a nice finish. This will also help to make the fine texture in the concrete more visible.

Step 7: Gluing the Brushed Aluminum Strip

I gave the aluminum a brushed finish by using some 800 grit sandpaper and a ruler (in my case an aluminum extrusion). I used it as a guide for the sandpaper block to sand just in one direction so that the sanding texture is evenly parallel aligned to the extrusion.

Then I used a box knife (the aluminum sheet was just 0.5mm thick) to cut a strip of the desired dimensions and glued it in place. The notch where the strip sits in was already contained in the mold.

Step 8: Moving in the Drivers

I got the drivers out of the old enclosures (they're just screwed in) and glued them into the new ones. The glue will also help to obtain an airtight seal between the concrete housing and the driver. They're also secured with one screw per driver just to be on the safe side.

For the cable I didn't want to reuse the old inflexible one. I wanted something with good haptics. So I got some highly flexible microphone cable that looks and feels much better. Since the drivers aren't too big, the 2x0.5mm² of the cable are sufficient.

When everything was soldered, I glued the top and bottom cap on. I used a lot of glue to ensure that the fit is airtight.

Step 9: Wrapping the Foam

For the speaker covering I used 3mm thick black polyester foam. Since I wanted it to be very smooth and soft to touch I opted for a 80ppi (pores per inch) foam. It's also important to use foam with open pores like they are used in filtration applications. This will allow the sound to pass through the foam with minimum distractions.

After cutting out a piece of foam with the right dimension in the height but a few millimeters wider, I used double faced adhesive tape to hold the foam in place. Starting on the back of the speaker all the way round and finally cutting off the excessive foam to get a nice seam.

And since you need to of these speakers, just start over from the beginning of this instructable:)

Step 10: That's It - for Now!

And that's how these speakers were made.

But this project keeps on going! Since there's still a volume control left to incorporate into this design, I will be continuously updating this instructable as the work proceeds.

And yes, they will also be made out of cast concrete, the volume control sure will have some great haptic and tactility.

If you think that I've made a good work so far, or in the best case got some inspiration out of it for your own projects, you can vote for me in the upper right of this instructable or here!

<p>This is so Heavy! I've always loved the look of concrete and to incorporate it into an unexpected objects design, priceless! How is the sound? Since the hard material doesn't resonate like wood or plastic there must be some discernible difference and decibel quality change. Please describe! I may try this with a guitar amplifier!</p>
<p>Hi Aerowise,</p><p>Concrete has a reputation amongst audiophiles as being the best material for speaker cabinets. However the weight goes against it in terms of practicality. But that doesn't really matter so much if you are just making a unit for domestic use as you wont be moving it around so much. If you look on pintrest there are lots of idea's and plans for building concrete speakers. </p><p>Hope this helps a little.</p>
Hi <br>I was wondering if I could get help/advice from someone on how to wire up a mono audio amplifier bored <br>It is very small and comes in a kit<br>That bit is easy but trying to wire up a minute microphone and an earphone speaker to and from the board is difficult,and all this to fit in a helmet
<p>Love the design.</p>
<p>What kind of concrete did you use? </p>
<p>Keep this up and everyone will know your name. You only need some time to become great.</p>
<p>DUDE !!!! I wish you lived in my neighborhood - you'd be sick of me coming over ! I think these are the coolest thing I have ever seen on 'instructables' and I check this site almost every day ! WOW - really good work AND a big Kudo's on having your sh*t together in your tools and workspace - these are an A ++ :) very impressive !</p>
<p>can we get more plans for the volume adjuster? </p>
<p>These might be the coolest speakers I've ever seen!</p>
<p>Rock solid speakers</p>
<p>Odd that there is one significant bubble at each corner only. You can mix a very small batch of thicker concrete and rub it into the bubbles. When I made a polymer concrete speaker enclosure I first thought I needed holes for screws /bolts then decided I could silicone-in my drivers and terminals port. Main advantages are they do not flex and it is a non-ringing material.</p>
<p>It's an impressive project but I'm curious about something.</p><p>From the pictures, the mold seems a little rough and that translated into needing to sand the concrete after curing. Is there a reason you didn't sand the mold to make the surfaces smoother? Would it have been harder to do that than sanding the concrete?</p>
<p>Thanks! After milling there are indeed some toolmarks left on the mold. Also the milled styrofoam surface isn't completely smooth since it's a porous material and the pores are then open. Here comes the grease into play, it closes the pores.</p><p>I tried sanding the molds first, but since most of the surfaces inside the molds are internal corners and i only needed to do two speakers i sticked with sanding the concrete. It's pretty easy when the concrete is just a few days old and not yet fully hardened.</p>
<p>Grease may close the pores (and work as a release agent) but it won't change how smooth the surface of the mold is.</p><p>I wonder if using plaster or bondo on the mold would work. I'm thinking that a fairly thin mix of plaster would seal the pores and be easily sanded smooth. Bondo might hold up better but is not as thin and would maybe a little harder to work into Styrofoam.</p><p>Then the grease over top of that.</p><p>Or would plaster, even with a grease coating, draw the water away from the concrete?</p>
<p>Keep in mind that you want to keep the fine details in the mold! Even with just the grease as a release agent, some corners come out a tiny bit rounded because the grease fills up these sharp corners. </p><p>Also it's not that the concrete surface directly molded from styrofoam is that rough. It feels probably like a 320-400 grit sandpaper when you touch it. It takes about 10 seconds of sanding to get it completely smooth.</p><p>If you want really smooth surfaces with fine detail directly out of the mold, you could try silicone as a material for the molds.</p>
<p>But... How do they *sound*? Thanks for this very detailed instructable. I am looking forward to your updates!</p>
<p>As I said, there needs to be some electronics and a subwoofer done before i can say anything about the sound. Since it's a 2.1 system, the single sound of just one component isn't that good. They only work together.</p>
A bit off topic. I really like you cnc machine, do you drawings / design for it?
<p>From the looks of it, it could be a Shapeoko, designed, produced, and sold by: <a href="https://www.inventables.com/" rel="nofollow">https://www.inventables.com/</a></p><p>A pretty affordable CNC-machine, looking to buy one myself :-)</p>
<p>Hi, I check their FAQ and it says it can't, I repeat CAN'T mill ferrous materials. I think it's much more easy to get materials such as iron than aluminum or others. The question is can we make it to mill ferrous materials like iron?<br><br>In advance thanks for your answer.<br><br>BTW a diferente touch to speakers, like it, and makes it a nice combo with the &quot;<a href="https://www.instructables.com/id/Real-Life-Super-Mario-Concrete-Thwomp/" rel="nofollow">Real Life Super Mario Concrete Thwomp!</a>&quot; and &quot;<a href="https://www.instructables.com/id/Concrete-Lamp-1/" rel="nofollow">Concrete Lamp</a>&quot; ;)</p>
<p>Milling ferrous materials isn't that easy on such tiny machines. You'll need something really sturdy probably with a lot of mass for milling steel.</p><p>Machines like the shapeoko are best suited for plastic, wood and within limits aluminum .</p>
<p>Yes, it's a homemade shapeoko clone. But there are some modifications compared to the stock shapeoko.</p>
<p>nice job!!!</p>
<p>Nice! What kind of concrete did you use? </p>
They look awesome.
<p>really nice speakers. I am a little worried about the speaker alignment to the back. It could be distort the sound a little due a horn effect. But what do I know. What do you think, is it worth any effort?</p>
<p>The volume the drivers sit in is a really classic and simple rectangular one. I don't think there will be any horn effects. Also it's a closed volume. Or did you mean that there needs to be more space between the drivers and the back of the housing?</p>
<p>I meant the speakers does not sit planar on the front and therefore the case opening for the loudspeakers form a small degraded horn causing maybe some problems. I think the speakers are already gorgeous as they are, but I was curious. Thanks for this instructable.</p>
<p>Hey, really cool!! How much do these weight aprox?</p>
<p>Great looking project! I think I just found new life for my old HP speakers.</p>
Awesome! This is pure genius, so stylish =)
very nice detailing... esp.. the depression to flush the aluminum strip with concrete. I am still wondering why you covered it with foam. concrete as such is a beautiful material for touch. nevertheless. awesome mod and documentation
<p>They somewhat resemble smd componet</p>
This more that just a speaker. Its beautiful. But alas i dont own a cnc machine , Iam still interested to see your finished product. People are awesome!
<p>Thank you! I think by simplifying the molds (e.g. no recesses for the M3 hex nuts and drivers etc...) you could make them by hand if you're a bit crafty. For example out of bent plywood or cardboard (varnished).</p><p>But if you've got a cnc on hand, this will simplify this step enormously, that's what they were invented for! :)</p>
<p>Awesome mod and the speakers came out looking great! Thanks for sharing!</p>
<p>very original! brilliant</p>
<p>Pretty sharp. the problems I see are you can't open the speakers back up, and the drivers are inside, not flush to the outside face. But none of that is likely to matter anyways.</p>
Concrete is so underrated!
<p>Nice work , great details in the instructable. thanks for sharing. What concrete did you select and why?</p>
<p>I used CEMII32.5R (no sand or additives) just because it's 2.50&euro;/sack :)</p><p>I don't think that you'll need a specialized cement or concrete for this application.</p>
Very neat and tidy very nice

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