Build your own Concrete Bluetooth Speaker (how-to)

now i've built loads of different projects for this channel ranging from various led lighting projects to scratch built computer cases and monitors to thermoelectric generators and even camera sliders but out of everything today's project is by far my personal favorite and what we'll be building today is an awesome looking and perhaps even more importantly an awesome sounding bluetooth speaker this one's something special as you can see the outer shell is made mostly out of concrete this looks excellent aesthetically and allows for these really nice curved sides that would have been pretty hard to achieve with other materials like wood it's also extremely dense which significantly reduces resonance this gives a very solid and confident sound quality that you generally associate with very high-end speakers and it's something that you have to listen to in person to properly appreciate now here at the front are the speaker drivers these have been specifically chosen because they can go very loud but they've also got really good bass and overall sound characteristics and they are driven by an amplifier setup that's again has been custom made for this which you'll soon see and it's all powered by these power cells these can just pop out and get recharged when needed these actually are a key ingredient to why this can go so loud without any distortion right i think it's about time that we got on and started building this thing about half of the effort required for this project will actually go into making the frame for moulding the concrete there are different methods of doing this but i'm showing one of the simpler methods here to make it as easy to follow as possible so we'll be making our frame out of a set of wooden pieces free templates for which you can find in the video description i had mine cut with a cnc router for accuracy but if you're careful you can totally do this by hand by printing the templates onto paper sticking them to some board and then cutting around them with a coping saw these wooden pieces can then be slotted and glued together like so and then thoroughly sealed with a mix of pva and water with that done we now need a large sheet of thick acetate which can be cut down to size and wrapped around the inside of the larger frame holding it in place with double-sided tape and around the outside of the smaller frame this gives a really nice smooth surface that will allow the concrete to later slide off it once it's set the smaller frame can now have a piece of acetate stuck to the top after which it can be screwed to the final remaining cutout with yet another sheet of acetate in between this can then be slid inside the larger frame as you can see there's a hole on the side and that's to make a gap in the concrete for the power cells by making a loop of acetate and sticking it to the inside so now we're ready to do the concreting we'll be doing a two to one mix for this so for every two spoons of sand we use we need to add one spoon of cement it's surprising how much is needed so mix about twice as much as you think you'll need so that you don't get caught out after thoroughly mixing this up some water can now be added bit by bit until it reaches the consistency shown here after which it can be spooned into the mold when you do this make sure that it gets right down to the bottom and has no air pockets i used a piece of scrap aluminium to help with this which was also useful for scooping the concrete underneath the power cell opening so once it's up to the top use the edge of a ruler to level it off and then place a final piece of acetate on top to help it dry flat and smooth with that done we can put the whole thing to one side and let it dry which could take up to 48 hours i actually made a fairly annoying mistake with mine which i'll explain when we crack this thing open but for now we can continue with the rest of the build starting with the electronics as we want the units to be very powerful with no audible distortion or interference noise we're going to use a particular group of components that have been specifically chosen for this project and you can find purchasing links to them all in the video's description the first of these components is the bluetooth audio receiver now this might look a little bit like a usb stick as it has a usb plug at one end but this is only used for power as it runs off five volts which is what a usb socket provides so if plugged into something like a usb power bank the module powers up and can receive an audio signal wirelessly via bluetooth and output it to its built-in headphone socket now with this the output is designed for a high impedance load like an amplifier rather than a low impedance load like headphones and if used with headphones the resulting sound is thin and lacks bass when used in this way thankfully though this isn't how we're going to be using it as it's going to be hooked up to an amplifier the amp we'll be using is a tiny tiny little thing but appearances in this case are deceptive as this board can output a whopping 30 watts per channel into 8 ohm speakers which is the same power output as this 20 year old hi-fi amp it can do this without any audible distortion too and the sound quality is clean crisp and punchy all for the grand sum of just over three dollars so to wire up the bluetooth receiver to it we can pop off its casing to reveal its internals these pads on the usb plug are the 5 volt power tabs and these pads on the headphone socket are its audio output before i solder my wires to this though i'm going to remove the connectors simply for neatness though essentially this is optional now to wire up the audio output to it we need a short length of screened audio cable which can be soldered to the audio output pads like so the other end of this can now go up to a dual gang potentiometer which will act as the volume control and it can be wired up as shown on screen here the additional wire coming off the potentiometer can now be hooked up to the amplifier's input tabs these are marked on the back as input left ground and input right don't worry about getting left or right the correct way around here as we can just swap the speakers over later if it's done wrong with that done we can now add the power wise the pads for which are labeled as vcc and gnd we want the bluetooth module to be powered by these same wires so we can expose a section of the wire slightly further up and solder them to the input tabs of a voltage step down board this little board takes the higher voltage that will be powering the amplifier and drops it right down to 5 volts making it suitable for using with the bluetooth module however if we connect the bluetooth module straight to this voltage step down board it will create nasty interference noise over the speakers here's an example of it this is caused by what's called a ground loop and fixing it requires one of these little dc to dc isolating converters this particular one takes a five volt input and then outputs it as another completely independent five volt supply this can fit in between the voltage step down board and the bluetooth module as shown on screen here so to recap we've got the power wires here which go directly into the amplifier uninterrupted they also power this voltage step down board giving a 5 volt output which goes through the isolating converter to power the bluetooth module this module receives an audio signal from say a smartphone and outputs it through the volume control potentiometer and then into the amp my potentiometer by the way has a built-in switch through which i rooted one of the power wise this means that it can be used to turn the system on and off we now need a front panel to mount everything onto this matches the internal dimensions of the concrete and is made of two layers the first layer can be made out of a nice looking piece of hardwood i've chosen oak for mine and to give it a deeper richer tone i first stained it with some wood dye to make it darker and then followed it up with some finishing oil to give it more contrast this looks absolutely fantastic in my opinion and i'll definitely be using this combination again in the future the second layer can simply be made out of fiberboard and features some cut out grooves for routing the wires as you'll soon see i painted the middle section of mine black so that when glued to the hardwood it gives a nice backdrop for the volume knob with that done the components can now be mounted to it starting with the potentiometer this can simply be threaded into the wood like so the other components can then be sensibly grouped around it and glued in place so now we need the key ingredient for this entire build which is of course the speaker drivers themselves i'm going with date and audio nd65s which are amazing little mini speaker drivers that are absolutely worth their weight in gold despite their small size they generate deep punchy bass and also provide a wide detailed soundscape that's both full and rich with a great sounding mid-range in all honesty these are the best small drivers i've heard and you can of course find links to them in the description mounting them is simply a case of screwing them to the back of the hardwood with some short self-tapping screws after which they can be soldered up to the amplifier's speaker outputs i rooted mine through the little channels to keep things neat and a volume knob finishes things off nicely now the power wise can be hooked up to a power source of anywhere between 12 to 24 volts for testing now it's important to give it a test at this point for two reasons the first is to check the left and right channels i use an app called pa tone for this and it lets you play a tone over the left or right channel and if they are the wrong way around all you need to do is flip it over because it is symmetrical and another thing to check for is the phase of the speakers so um if a speaker set is out of phase one will move in whilst the other moves out and this sounds super weird so to check it play a piece of music listen to it carefully and then swap the polarity of one of the speakers what this does is allows you just to by ear tell if it's in or out of phase and it's really obvious um when you hear them in comparison so try it both ways around and you should be able to tell easily enough so by now hopefully the cement has set so uh time to deal with that removing the outer mold is easy as the pieces can be lifted up and then the acetate peeled away once i'd removed mine i realized that i've made a pretty big mistake with my mold as the edges of the concrete at the very bottom were crumbly and lacking in strength turns out that this was caused by not having properly sealed the gap between the inner and outer moulds which allowed the water in the mixture to seep out at the bottom as the presence of water is essential for the chemical reaction that causes concrete to stiffen a lack of it causes it to fail as seen here so when you make yours be sure to seal the base of your mold properly so that nothing can seep out of the bottom cork should do nicely for this so in an attempt to fix mine i brushed away all of the weak concrete and added back the acetate mold filling it to the top again with some more cement once set this still didn't look particularly good especially as initially i wanted a nice smooth front with no rough looking edges and this really wasn't up to scratch so i ended up sanding down the inside edge and resealing it with a light layer of cement which i then covered with some cling film this film kept the moisture from evaporating and prevented the cement from having a rough finish when set also thanks to the creases it gives an interesting texture when peeled away to make this stronger however i added some pva and then painted it with acrylic paint to emphasize the ridges the end result is that it looks like fabric that has been pulled inwards getting rippled in the process it's something that you'll either love or hate but i personally prefer it over the rough sandy texture that i would have had otherwise and it's grown on me since finishing the project and i like it quite a lot so despite the mistake i think it's just about rescued now interestingly the acetate has given the concrete an extremely smooth polished look and while thankfully there are no large air pockets there are a few air bubble crevices which look awesome and prevent the surface from looking too uniform and boring so with the concrete shell sorted we now need something to mount the front panel to i'm using a piece of cut fiberboard with some ribs on the inside which can simply be glued in place now it's very important for this to be sealed right around the edges so that no air at all can escape around it as any unsealed gaps severely harm sound quality and it's not something that should be underestimated i used cork around the inside just to be sure using the camera on my phone to check its coverage with that done we now need to work on the battery system for powering the electronics for this we'll need a set of five or six lithium-ion batteries with protection circuits if the battery doesn't explicitly say that it's protected do not use it as it would be very dangerous to do so without the protection circuit because if they get over discharged it can cause a fire or explosion when they get recharged again i suggest that you avoid ebay and amazon for these due to fakes being all too common and instead go with a reputable electronics store like rs online i'm using some of their own brand batteries that's from my testing perform exactly as advertised these need to be put inside some empty battery bank tubes these are super cheap but we do need to remove the electronics and replace them with xt60 connectors instead which needs to be soldered up with the correct polarity now some short pieces of pipe can be inserted and glued into a fibre board cut out for the batteries to slide into pipe with a 22 millimeter internal diameter should be perfect for this now we'll be wiring all the batteries up in series so we need to get some xt60 sockets and solder them together like so making certain that the polarities are correct they can then be glued in place at the bottom of the tubes so that the batteries can slide down and get plugged in once this unit has been securely glued inside the concrete again making sure that there are no air gaps it can be capped off with another piece of stained hardwood making it look very nice indeed so the last thing to do now is solder the battery pack wise to the amplifier circuit after which a piece of sponge can be stuck around the inner edge to help seal things when the front panel gets pushed in and screwed tightly down by threading into the ribs behind now the batteries which i will now call power cells because it sounds cooler can be inserted into the sockets and then it's ready to use so i'm sure you guys are wondering just how does this sound well in short very good it's something that's hard to convey over a video because it depends on what you are listening to it on at home but here is an example just to give you a general idea power on pad [Music] where pity dwells the peace of god is there to worship rightly is to love each other each smile a hymn each kindly deed [Music] come on [Music] so hopefully from that you could hear that it has a very full sound with good bass and very little distortion even at the very high volume levels and that is pretty impressive personally this is the best sounding bluetooth speaker i've heard and i do like my speakers so hopefully that's saying something now some time ago on the channel i said this i've just gone over a thousand subscribers which if you think about it that's quite a big number now it turns out that i've almost hit a million subscribers now which is an incredible number so thank you very much to everyone who has subscribed it's absolutely amazing and as i'm not doing a particular celebration video or anything but i will be doing a questions and answer video so if you have any questions that's not specifically about projects but more more general questions like about the channel or me or you know what kind of uh yogurt i like i don't know but anything you like just ask it in the comments below and i'll try and answer them in the questions and answer video so i think other than that this video is finished so i hope you've enjoyed it it's been a pretty big roller coaster ride and the result is absolutely amazing in my personal opinion so i hope i see you next time um or should i say i hope you see me next time because i've never i never see you guys so i don't know why i say that anyway goodbye for now by the way be very careful when you're working with concrete because somehow i managed to get some on my wall and on my window which is absolutely ridiculous so it gets everywhere so be careful if you're doing it in a home environment and yes i did get some on the carpet as well so you

Channel: DIY Perks

Views: 2,396,399

Rating: 4.9303412 out of 5

Keywords: speaker, amplifier, build, electronics, bluetooth, wireless, stereo, drivers, amp, audio, hi-fi, diy, make, volume, loud, music, diy perks, boombox, dayton audio, nd65

Id: a43LXqRwQC8

Length: 19min 53sec (1193 seconds)

Published: Sat Sep 30 2017

Reddit Comments

[u/LovecraftLovejoy]

No

[u/beige4ever]

maybe good for listening to... rock

[u/xuddish]

my concern is that the drivers are too far apart for quality and volume, and too close together for stereo. it just doesn't make any sense.... that is excluding the whole portable audio or bluetooth. fidget spinners of the audio world............

[u/DAM159]

That was dumb

[u/the_blue_wizard]

It is as good as what it is. Tiny speakers, weak amp, etc...

For what it is it probably sound fine, but it is what it is.

[u/analretractions]

These are the parts he has used:

Driver

Amplifier

Bluetooth Reciever

Edit: Formatting..

[u/XxGreeninkxX]

No

[u/2crowncar]

Oh no! They cut off Wall-e's head.