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IndestructibleGhettoblaster

Page history last edited by PBworks 14 years, 8 months ago

The Boom Box in a Box Hack


The indestructible ghetto blaster hack started off when I found a remote 1960-70 Closed Curcuit Television Monitoring station at the local dump. I gutted the insides except for the faceplate and stuck in the gurage. About 6 months later, and right after I had finished the Back Pack Sound Hack, I had the inspiration to transform it into a sturdy and loud ghetto blaster.

 

The case is made out of welded aluminum and has an aluminum covering that latches on with 4 strong overcenter hinges. The original face plate inside the case was designed to be taken off if nessescary by unscrewing four cool hing mechinisms (looks like a screw with a smatt pice of metal attacked to the face plate, as you unscrew it, the metal piece retracts from underneath a lip in the case. Also two metal handles were attached to the face plate to lift it out of the interior of the box.

 

 

I started by removeing key pieces of the face plate then I created two new faceplates out of 1/4" hardboard, one went undeneath the speakers and was screwed to them and the top one went above the speakers (two at 2", one at 4"' two at 5", and one at 8") both were held together using longer screws.

 

After adding the speakers to the new faceplate, I wired everything in mono coming from the out put on the donor amp. The reason for this was to facilitate the addition of the toggle switches to be added later and it wasn't completly nessescary to have a left and a right channel of sound in such close proximity (I did the same on the back pack). It also didn't matter because the secondary output from the amp would be in Stereo, so it would be possible to have an external stereo system.

After finishing the basic faceplate part, I drilled the holes for the potentiometers in the thick guage aluminium (I found that to effectivly have the 3/8" twist bit not walk all over the top of the case you must first center punch all of the holes) After drilling the holes for the knobs I located the correct position for the power button and two microphone inputs and drilled these. Next I layed out the location of the paths for the 5 sliders on the equalizer. I drilled the top and bottom of each of the little rectangles and then cut the waste in between them out with a cut off wheel in the flexi-shaft of my dremel tool. The result was very professional looking. I then drilled tho hole for the power indicating LED (the little red dot in between the equalizer and the small brass plate in the picture above). Finally I drilled the hole for the input to the ghetto blaster. (more to come on this later)

 

 

I now attached the curcuit board directly to the bottom of the case and with a little more patience and work, the whole thing was functional. However, it did not look nearly as cool as I had hoped. So I fixed that problem.

 

 

I added a false bottom to the case by cutting out a template of the inside of the case from paper. I accounted for the nessescary hole for the input, which ath the moment was still inside the box! (notice the black plate with the stereo connections just right of center in the false bottom, this was the input, output, and DC input from an AC/DC convertor.) I gave the false bottom a simple matte black finish with a flaming G. F. I. logo in the middle of it. (close up below)

 

 

Now in order to make the input work well and look good I had to pull out all the stops. I started with the 3/8" hole in the aluminum box, This was way too big to put the small 1/8" stereo jack into so I made a small plate out of thin guage brass sheet with a 1/4" hole in the center. I cut the plate out using a jewlers saw and a bench pin. I held the tine oval piece of metal using a jeweler's ring clamp so i could hold it on top of the bench pin with one hand and cut with the jewelers saw in the other.

 

These are images of a jewelers saw, a bench pin and a ring clamp

 

After cutting out the shape with the jewelers saw, I used a file to clean up the rough edges. I then drilled a 1/16" hole on one sid of the oval. I used this hole as a guide to drill a hole in the box to go directly underneath it. I then rivited this side into place. Next I drilled and rivited the other side into place as well. I attached the 1/8" stereo jack input to the plat by screwing it in. Now to add the final touch, I cut a standard stereo right/left cable in half, stripped one half and soldered it to the 1/8" input jack. I soldered the right to the right, the left to the left and the ground to the center. Now I can plug the stereo cable dirctly to the input right and left from the 1/8" input, or I can use it as an output by switching the plugs to the next set. Or I can plug in an alternate input source. The good thing about this system is that I can plug a CD player/MP3/iPod into the input on the outside of the boombox using a 1/8" male to male jump cable (which is stored neatly in the front cover along with a screw driver when the ghettoblaster is turned off) and I can walk around playing music. (I did a similar hack to the BriefCaseBoomBox)

 

 

I finished off the front faceplate with a coat of matte black paint and some more logos and covered the exposed backs of the speakers using some blue nylon ripstop material. Also, the three toggle switches on the front are used to turn on and off individual banks of speakers (two conserve battery power and adjust the sound quality). The left toggle controls the left 5" speaker and the two 2" spreakers below it, the middle toggle controls the 8" middle speaker, and the right toggle turns on and off the right 5" speaker and the 4" double cone speaker directly below it. With all speakers on I can acheive terriffic sound quality but it drains the batteries (8 D cells) rather quickly), with just the center speaker on I can acheive greater efficiency at a higher decible range but the sound quality is lacking. The best quality is reached when this boom box is coupled with the back pack (and or other ghetto blasters I have made) and put on bass duty. It does have slightly better base range than the others and them all together acheives a higher level of volume (which is critical while D.J.ing on a crowded noisy bus full of runners or at track meets (where our tent is always the crazy loud one for obvious reasons)

 

Because of the aluminum front cover there was no need to add screens to the front of the speaked because as it is being moved, its most vulnerable time, the cover is on it and nothing can hurt it. For two days straight I worked feverishly on it to get ready to pump out music for the first mile time trial for cross country. I managed to get to the practice on my bike in time but it ended up raining during the trial, so we didn't have music to run to. Also the indestructable ghetto blaster is good because of its box shape which reflect the sound outwards unlike the Back Pack Blaster which inherently does not as good acoustic properties. The track meets are made a lot more fun with this boombox on duty, a CD player and lots and lots of CD's.

 

 

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