This project has been going on for the last 8 months and consumed quite a lot of my spare time.
I don’t think I’ll ever attempt anything as big or as complex ever again... so I thought I’d share it as I did the last one.
(Though I have a feeling this will take a bit longer to write....)
Step 1: The Initial Idea....
This whole thing started - literally from some redundant emergency lights.
If you’ve read my other instructable you’ll have read that I’m a bit of a hoarder, cupboards full of stuff I’ll “get round to using one day” well as true as that is, what I didn’t have was a battery.
The redundant emergency lights piqued my interest as I wanted to know what the batteries were like. Turned out they were strips of 5 cells, all 1.2v each.
Before I even knew what I wanted to make I charged them up and was surprised at the capacity, and how long they stayed charged for.
A portable CD player was the most recent thing I’d messed about with... it was then I knew what I was going to create.
When I was younger I always used to dismantle all manner of electrical goods, far too curious, my particular favourite were CD players.
I decided almost straight away that this one was going to be very very technical. I measured two of my EVOR04 modules (from Bulgaria, via eBay) and also measure the drive units from the centre speakers (the ones whose amplifiers are used to drive my other project) left a gap in between for the voltmeter and the dials, which are connected to a tone control board, with bass, treble and balance (there is a volume control too, but that is mounted inside the cabinet, as the volume is controlled by the CD player) measuring all the components on the front panel is what decided my height and width. The batteries decided my depth.
I started off with marking speaker and display locations, then got onto the hinged CD player.
The original button controls for the CD player are still on the main board, but I have tapped off the volume up and down, play, next and previous, these are now all switched by momentary 12v illuminated buttons mounted on the top of the case. The original button which is pressed once the original lid was closed, enabling playback, is done via a matching button of the latching variety.
As luck would have it, the hinged part of the top is what allowed future modification to happen, if I’d made it as a sealed unit I’d have had no access to the Innards. And it was only ever designed that way for vibration isolation.
There are several drive units in addition to the ones mentioned above. In the top panel there are 2 Yamaha 4” drivers, 2 2.5” drivers and a pair of 1” tweeters made by Eastech. These are powered by 3 separately switched 2x15w 12v amplifiers, one for the fronts, one for the Eastech units, and the final one for the Yamaha drivers. These all have separate volume controls.
The shallow depth of the Eastech drivers allowed a charger to be placed below them, so power was now delivered via a rear mounted figure-of-8 socket wired to the charger, and batteries when it is unplugged.
There are also 2 voltage regulators inside this cabinet, one providing 4.2v to the CD player and the other providing 5.2v to the spectrum analysers in the front panel and the tone control board.
As you can imagine, there are a LOT of wires inside this cabinet, you can see them on one of the photos, along with the hidden volume control, which actually acts more as a gain control for the 3 amplifiers.
The cabinet itself is made from 3.6mm plywood, edges with right angle corner pine, sanded and varnished in Satin Dark Oak by Ronseal.
I only had a small tin of this, as the original cd unit was supposed to be the only thing I was making...
sometimes things don’t go according to plan, though, and I ended up buying another, larger tin.
Step 2: Modification Time...
I lived with just one unit for a few weeks, showing it off to people, and basically just “using” it. Listening to CDs that I’d not listened to for years, and playing with the spectrum analysers.
I realised soon after, that I had enough wood to make a second unit. I quickly decided that I wanted to build one to house the usb/Bluetooth player so I wasn’t limited to just CDs anymore.
I added 4 more speakers, 2 more spectrum analysers and an amplifier to the design, along with several relays.
The immediate problem I ran into was getting the two units to work together. This was solved once I found some 24pin plugs and sockets. I sent the audio feed from the CD player down into the 2nd unit, where I used another latching switch via 2 relays to switch between the cd audio and the usb audio. This signal is also sent to all 4 spectrum analysers, so they’re not locked to only operating with the signals from the housed in their respective cabinets. Volume is still controlled via the 3 amplifier dials on the top panel, and the newly added 4th amplifier.
The 4th amplifier runs 4 Philips 2” drivers on the sides and rear of the unit, 2 side facing and 2 rear facing, and wired to only the L+ and R+ from the amp, almost like a crude ‘surround sound’ using only differential signals (very similar to the rear channel of Dolby pro logic)
These drive units are sealed into their own enclosures to prevent any cabinet resonances, and the amplifier is mounted in the front panel to adjust the volume of only the 4 ‘surround’ speakers. There’s also a switch to turn this amplifier off, and the final latching switch (through the 24 way interconnect) switches off the part of the 5volt circuit, turning off the spectrum analysers but leaving on the tone control board.
I lived with this as a 2-piece hifi for only a few days, then I decided I wanted to make a 3rd unit as it was starting to look a lot like separates....
Step 3: Turn It Up!!! (4 Times Though)
I was starting to get annoyed with having to adjust 4 spearate volume dials to turn it up or down, so decided to make another unit featuring one universal volume control. This volume control has its own display, showing between 0 and 84.
As I had wires between the source select switch on the 2nd unit going back up into the first one to the amps, i just re-routed that to go into the 3rd unit first so it could be adjusted by the rotary volume control prior to going into the 4 amplifiers. This requires a 5v supply also which I also had travelling through a pair of the interconnect cables, this also got re-routed. I also used 2 of the cables to provide a switched 12v to this 3rd unit, but not the 0.5a 12v feed which supplies the usb module, a fused 5a one, as I wanted to add more illumination...
The cds is mainly been writing for playing on the unit are 8cm mini CDs, which I’d bought a lot of. So in the 3rd unit, which so far only featured a volume control, I made a cd storage rack, this is illuminated by 2 strips of RGB LEDs in he centre of the unit. To balance the look of the unit I also made a small white led illuminated enclosure with a little monkey in it, this little monkey was given to me by my son, I think it may have originally came from a kinder egg? I didn’t want to lose it, so now he’s now encapsulated in his own little box. There are two switches below this, one for the RGB strips and one for the monkey.
At the rear of this unit there is a 4 channel amplifier and a 10 way spring-clip speaker terminal strip. This is operational, but was only ever briefly used, but not yet. Needed to build some speakers first.
I had a more pressing issue to deal with first....
I now had a ridiculous amount of components being run from the emergency lighting batteries in the top unit.
Time to build a power supply.
Step 4: Power to Supply... and a Storage Box to Boot.
The power supply I use whenever I’m making stuff is a moonraker 375w bench supply, set to output 13.7v through. This received the usual treatment of extending all cabling to mount on the outside of the cabinet.
The power switch and the volt/amp meter were moved first, followed by the switch which you use to chose whether the meter is showing volts or amps. The power supply also had a cigarette lighter socket on the front panel originally, so that was moved outboard too.
The LEDs which originally illuminated the meter were moved at first, but then disconnected, so they could then be powered by the switched supply from the power switch on the top panel, so nothing is illuminated until the whole thing is turned on, even though the power supply is still energised.
Linking the whole thing together was confusing at first, but I soon ended up making a socket/plug ironically intended for hard drives in the first unit and the power supply. The original negative cable from the batteries goes down to the power supply through the black wire, where it is shorted out with the blue wire, this white wire switches a relay which changes the positive battery terminal for the positive from the power supply, this means when everything is plugged in to the power supply, the only thing the battery is used for is energising the coil on the relay, and all components are fed from the power supply, but as soon as it is unplugged - the disconnect between the black and white wires turns off the relay and all components are fed from the batteries. For this reason, and for the purposes of being able to remove the top unit for portable use, the top unit is always plugged in; keeping the batteries topped up. This uses less than 5 watts of power as a trickle charger. The power supply uses 11watts when the system is turned off, this increases to around 70 watts when the whole lot is turned on. It doesn’t use as ridiculous an amount of power as you might expect with it being all home made.
I made a storage box for the bottom of the stand, just because. This contains all the components for my next projects :)
Step 5: Now I Have More Power - I Need More Speakers
I had 8 Cambridge audio BMR drivers, admittedly, they were still inside the company’s ‘minx’ satellite speakers, but that soon changed.
I set about making some 105cm tall floor standing speakers for the unit, it’s all good having in-built speakers when it was only one piece, but now it’s a 4-piece it needed separate speakers. These have 3 BMR drivers per unit with a vented design, but only once it had gone through a myriad of chambers and slots inside the cabinets.
They’re not particularly bassy, but I never expected them to be, using 3 small drivers. They do, however sound very musical and well-rounded.
The other two drivers were built into smaller cabinets, which at that point in time I had no use for, they were literally just extras and offcuts, so why not??
They later turned into rear speakers, but not until the next step...
Step 6: Multi-channel Upgrade
I didn’t think I’d ever get around to using my JBL ms8 again, for those who don’t know, this unit integrated into a vehicle to creat a ‘logic7’ surround sound. These devices are literally incredible. This was taken out of my car 3 or 4 years beforehand and left in a cupboard along with everything else I have no immediate use for.
This was dusted off and prepared for the 5th unit of the stack... it just happened to be in the same box as my JBL KD-AVX77 so I measured the units to see if there was any way they’d both fit into the form factor I’d created with all the other units, 450mm x 250mm x 115mm. To my amazement it did - at a push, so I pushed.
The Jbl obviously converts the 2 channel audio from the cd or usb module into an 8 channel amplified signal, whereas the jvc is there literally as a pass-through, it is only used as a line-in line-out device, purely because I had no other use for it, was never likely to, and I love the full sized screen it has.
Once the whole stack is turned on and the brand names have been on the screens, they drop back to having a red ring around the screen of the jvc, and the level controls for sub, centre, balance and fader on the Jbl. When anything needs adjusting the remote control holder for the Jbl is glued onto the side so it doesn’t go missing.
...and now I have a use for the small BMR cabinets I made earlier :)
I had *every intention* of this being the last thing I made...
-but then decided the system needed a sub... and a centre speaker. The Jbl had two outputs which weren’t being used for anything, what else was I supposed to do???
Step 7: Subwoofer (mark1) and the Centre Speaker(s)
The subwoofer uses the drive units which were in my other project, this was sacrificed quite early in the manufacture of this system. In fact, it was sacrificed even before the 2nd unit was made, mainly for the switches and the usb panel.
The monitor audios actually work surprisingly well as subwoofers, powered by a Mission amplifier panel, I forget the model number of the original sub, but the amplifier plate was another thing I had just waiting for a use.
The front panel of it has a blue led illuminated level meter from an old pioneer hifi and a low pass filter with 2 controls for level and crossover.
Ventilation for this is provided by the port on the front.
As the signal for the subwoofer is taken *after* the tone control board on the primary unit, the bass is adjusted through everything on the system, so the subwoofer could be set-up and left alone, with any tweaking being done and the top unit.
All in all it works (or worked) quite well, but didn’t reach quite as low as I’d hoped. Still good though but with virtually no audio below 46hz using the sonic app.
Once I’d got the sub out of the way it was time to make the centre speaker, or centre speakerS as it turned out.
I couldn’t decide on a design for a centre speaker with wouldn’t look out of place in the system, with a matching front and rear stage and no BMR drivers left... I quickly regretted using three drivers per floorstander, if I’d only used 2 I’d have 2 left for the centre speaker.
As it happened, I’d just bought some LG home cinema tall boy speakers for the princely sum of £1.20 as I wanted tweeters, only to find out these had none, they only had 2 x 2” drivers per unit -or did have until I dismantled them. These are 16ohm drivers rated to 50 watts, I suspected the power handling doubtful, but the impedance proved correct with a multimeter. These little things though are actually quite impressive, I wouldn’t be surprised if they could take 50watts and laugh at it!
I decided I was using 4 of these as my centre speaker, attached to a tv stand, well monitor stand to be more precise, all made from the same materials as everything else with 2 shelves (offcuts) and an Apple TV under one of the shelves.
The idea for using the monitor and creating the stand in general was purely down to finding a simple plastic VESA mount in the poundshop!!!
The outside edges of the stand have RGB LEDs around them, and all electrical cabling (and plugs) are mounted to the back of it, hidden by the strip Wood I used as a stand-off for the LEDs to shine in the wall.
The headphone socket on the rear of the monitor feeds starlight into the 3rd unit I made, the one with the volume control, as it had a miniature on off switch mounted in the front panel. This originally turned on the 4ch amplifier in that unit (now defunct) but now energises two relays, one for left one for right, switching between cd/usb/bt and now the input from the monitor. As mentioned previously, all spectrum analysers and amplifiers are *post* volume control, so now all components react to the monitor’s output.
Once the sub and centre channel were wired in it sounded good, but not good enough. The JBL has quite fierce crossover roll-off slopes set up, and the crossover point between the subwoofer and the centre speaker was set quite low... too low for the diminutive LGs to ever hope to reach.
The solution killed 2 birds with one stone... if 2 onkyo 4” drive units can be described as a stone??
The picture that shows the Crossy road screen and the led illumination also shows how ‘uneventful’ the bottom of the stand was, just ending bluntly at floor.
Now it has a separate speaker enclosure, with the two onkyo drivers in, angled towards listening position, and filling in the gaps between the sub and the centre speakers. 2 of the LGs had 1.5uf capacitors added to make them tweeters. I can’t remember what I did with the remaining 4 speakers connected to the centre channel output of the JBL, but it can go down to 2ohms on the output anyway, and wherever it was I ended up doing seems to work fine. There’ll have been reason for whatever I did, I just can’t remember.
So, now I have a CD player, usb and sdcard player, Bluetooth, Apple TV, a monitor and 7.1 channel Logic7 audio...
...the only remaining step was a DVD player...
...any guesses on what the next step on this instructable is going to be??
Step 8: (HD)DVD Player Unit
I bought a 2nd hand Xbox 360 years and years ago, with the add-on HDDVD drive and several discs, the red ring of death finished that off, so I was left with films I couldn’t watch. Ebay fixed that for me with the Venturer HDDVD player, well, two of them in fact. I bought the 2nd one, and a lot more films, just so I had a back-up player, as they’re only going to get rarer and rarer as the years go by... something I’ve helped along by destroying one and reappropriating into my own case to match the rest of the units, after all, how stupid would it look with it in its original guise underneath my stack??
It wasn’t a straight copy, the boards all needed to go in at different angles to get it to all fit, the original unit was a lot bigger than mine, also I added a thermometer and a 4.3” monitor in the front (also, just because)
Cutouts for the power switch, remote sensor, vfd, monitor, thermometer, disc tray, power connection and hdmi were all cut out well before putting any components inside, as I wanted to minimise the risks of sawdust getting into the drive. Toshiba made these and they are almost definitely unavailable now.
As this is HDMI’d straight into the monitor (albeit through a switch box between Apple TV, ps3 and HDDVD) the audio still enters the rest of the unit through the monitor’s headphone socket. So it is as integrated as everything else.
Included in these photos is an overall dark photo, showing what the whole stack looks like in subdued lighting, this doesn’t have the cd starage illumination or the DVD player turned on though.
That would’ve been ‘it’, no more to do, no alterations to make, nothing else required... but the subwoofer’s lack of low end ruined films for me. I know many home cinema systems could never hope to reach below 50hz, but the amount of time I’ve spent on this whole project made me feel as though I should’ve achieved better....
Back to the drawing board.
Step 9: Mark 2 Subwoofer
So, time to replace the sub....
I decided I no longer wanted a mains powered subwoofer amplifier, I wanted a 12v amplifier this time around.
In my box of dead electronics I had an amplifier board from an underseat subwoofer, this used a flat 8” DVC drive unit. I don’t recall the manufacturer name. However, the amplifier is actually very very good. Why it reaches as low as it does is beyond me for the job it used to do?!
Anyway, this has been re jigged and re packaged. If the original plug had been used, this cabinet would have been too deep to sit above the subwoofer, so cables were soldered directly to the board.
The original enclosure *was* the heat sink for this, but now that has gone I found 2 replacements. These are purposely on display in the new enclosure, as is the circuit board, visible through the top -via a speaker grille (from the old TEAC car Center speaker, which used to cover the woven glass drivers in the CD player unit) the circuit board and the heat sinks are illuminated by RGB led. There are only 2 dials on the front, one is level control, one is frequency.
The subwoofer is only possible because I “collected” 2 Philips speakers from Schpock, these are bookshelf speakers with aluminium cones and ‘woox’ passive radiators in the top.
I didn’t buy these specifically to build a sub out of, why would you? Bookshelf speakers?? But oh my days what fantastic drive units these are. There are a few videos on YouTube showing these getting absolutely battered and they love it. Such impressive little speakers. They’re 5.25” I think, and the passive radiators are the same.
Before I made the subwoofer amp, I used it to test these Philips drivers, and jeez do these things bounce!!
Right then I decided I could make a slimmer sub than the existing one if I used both of these drivers.
These are both mounted at an angle in a sealed cabinet, this then has a chamber above it to make it a bandpass cabinet, topped off by another baffle -also at an angle- containing the passive radiators. This passive radiator area is in itself an enclosure, with the top being there instead of being missing.
There’s probably a name or an order or something else for this kind of arrangement, I must admit I’ve not seen one, not sealed/bandpass/reflex (radiator, not port)
This performs so so much better than the sub which preceded it, and drops so much lower.
As there’s a window through to the drive units I put LEDs in there, to watch the speakers, and they barely move. I’d say the passive radiators move twice as much as the actual drivers, which is nice as thatscall open, and clearly visible as they’re also illuminated.
There is a shelf inside the bandpass part of the chamber, covered in foam so as to stop it sounding boomy -which worked perfectly. It’s easy to over drive it though if the amplifier is set to the lowest frequency, but that is 40hz, which no other speakers in this system extend down to, do there no point keeping it that low. Doing a test with a separate spectrum analyser it seems the best frequency to cross the amp at is 80hz, then it meshes nicely with the lower frequency centre speakers.
Step 10: That’s It.
All done, nothing else to add.
There’s a bit of everything in this system, a lot of unnecessary components have been added, but hey, it would’ve been a boring instructable without them all.
The photos added to this step show all the evolutions of this system.
To start of as a stereo CD player and end up as a telly operational Logic7 Bluetooth DVD playing home cinema system!
So there’s nothing else to do now.....
Although, if I mange to find a suitable minidisc player I’m adding another section.
Thanks for coming on this journey with me.