Speaker Panel – Electronics

After lunch yesterday I set about the speaker electronics.

I have a bunch of speaker “guts” that I ripped (carefully of course) from a cheap (fiver ($10)) set of speakers I got from eBay.

On the inside of the speaker panel, I mounted the odd shaped speakers as close to centre of the “speaker holes” I cut in the panel, with a few 1/2″ (12mm) screws – I almost burst through the facing surface with one screw tip so I was very careful with the rest.

I’ve had a real debate with myself about the speaker controls – there are going to be times when I want to adjust, as a minimum, the volume if not the bass/treble, so how can I get at the controls without compromising the semi-authentic look I am going for?

I could cut a little hole in the speaker panel and adjust the volume with a small screwdriver, I could mount the speaker controls on the top or back, etc.

I’ve decided that I’ll mount the controls on the back of the speaker panel, and access them through the “vent panel” (to be constructed) and somehow make the vent panel “quick release” – by doing this, I can also put the controls for the marquee backlight here and access those too – maybe even the USB ports I intend to install, although I still think I want those more accessible – a decision for another day.

So the controls and the AC/DC transformer are mounted in the centre of the inside of the speaker panel. One concern I have is the heat generated by the transformer – these do get warm and I’ve mounted it in direct contact with wood – not inspiring. I’ll keep an eye on this and run the speakers for several hours – if I’m concerned enough I’ll drop a little metal panel between the transformer and the wood. I sense this is more likely than less, as I’m not keen an explaining to the wife why and how the house burnt down.

You’ll see that I had to cut plenty of wires to get the “guts” out of the speakers, as such, there is now plenty of soldering and repairing of cut wires, and a tidy up job on the wiring using my handy cable tie mounts.

Hook it up to my iPod for a quick test – works first time, no crackling or interference. An unexpected but not unpleasant effect is that the sound is a little muffled at a distance and at angles if the listener is not directly under the angled speaker cutouts, but perfectly clear and sparkly directly undernearth – this seems very reminiscent of my childhood memories of arcade machine sounds so I’m not unhappy at all.

THE REAL TEST!

Now that I have the speakers, monitor, and controls all working, time for a “REAL” test – I hook up the cables to my “as yet unmodified (as in, still in it’s pale cream case)” PC and run the latest version of my gMame interface software available at sourceforge (for those joining us late, I’m writing my own interface software in Java as well as constructing the cabinet) – it’s all working beautifully, and using the arcade controls with my software is working really well.

I’m a very happy bunny at this stage. The only panels left are non-electronic ones, except for the panel that will house the reconstructed PC, and I hope to make a start on them the weekend.

A lot of Java, and a little woodwork…

Today I spent about 5/6 hours working on the software available at gMame@Sourceforge – although I haven’t uploaded my changes as they are part way through.  I’m trying to add a lot more error handling so that the new user is not put off by odd error messages just trying to get the thing started.

I’m trying to get to grips with CVS (the version control stuff) so that I can keep my up to date working copy at sourceforge instead of a number of memory stick.

Tonight, when I got it, I had half an hour to install the marquee and the speaker panel, then offered the monitor panel back in.  As pointed out in a previous post, I’ve finished the monitor panel too early – I need to unpick it all and pass it back over the table saw to get the right angles top and bottom.

Next time I get some time on the project (hopefully Thursday morning) I’ll either do the electronics work, or get the monitor panel angled and installed, or hopefully both.

A picture of everything in place (monitor just positioned not installed) to get your appetites wet…

Speaker Panel – Part 1 – Woodwork

So, Sunday came and again, little to do, and again, little money, so the impossible happened – another permission slip to work on the project. Amazing. I’m sure that I’ll have to pay for this somehow in the future…

I could follow the process as per the monitor panel, cut a hole, bezel, the put a cover (speaker cloth, not perspex), but I want to be cheap and I think my process is a bit more artistic, and reminiscent of the cabs I played on many, many, many years ago. Put simply, I’ll break apart some cheap (but reasonable quality – it’s not as if arcade games have hi-def sound) speakers that I got from eBay for a fiver ($10), cut a wooden panel, drill lots of small holes to let the noise out, paint it, install the speakers behind the small holes to let the noise out, and install it.

The process:

1. Bust open! some cheap speakers, and save all the insides, tossing way the plastics – PHOTO
2. Cut a panel to size – this panel will be mounted at 45 degrees so for an average 5′-6′ (1.5m-1.8m) person it should point at the face/ears
3. Draw out my speaker-holes-pattern on the panel – I’ve set my trusty compass the max width of the speakers, spun a circle, reduced the radius by 1cm, spin the circle, reduce, and so on until I have a bunch on concentric circles – repeat for the other speaker.
4. Draw intersection lines at 0, 22.5, 45, 67.5, and 90 degrees – then draw some crosses when lines intersect without cramming too many holes too close together –
5. Down to the bench-drill, and with a 3mm bit, drill all these little holes, then slightly countersink them on the facing side for aesthetics.
6. A coat of MDF primer later, and the counter sunk sections have swollen – this is fibreboard I remind myself, and my countersink must be a bit blunt – DO THIS DIFFERENTLY – perhaps a sharper, larger drill bit inside of the countersink would have a better effect. Some careful sanding and re-drilling of my little holes and I’m ready for 2 coats of matt black –
7. This paint I’m using is pretty thick stuff, and I don’t want to brush it into the carefully constructed little holes as it’ll surely clog, so I’ll get a good permanent marker and fill in the bits of wood inside the countersinks that the paint. missed.