This BoomBox is my second attempt at a portable powerhouse. The first attempt turned out great and sounded great but was WAY too heavy and not the easiest thing to move around.
The goals for this radio were simple
- Long (Playback time)
Step 1: New Design
My first Radio used:
- 1/2" MDF as the main material
- pyle (Pile of dodo) Speakers
- 18 Amp hours of sealed lead acid batter
- Cheapo lepai amp
Rodayo Mark II:
- Balsa wood subframe truss design with balsa veneers reinforced with fiberglass chop mat and 6oz glass in places
- 12 amp hours of lead acid battery
- 300watt clarion D-Class 4-Channel Amplifier
Step 2: Construction
I used regular Cyanoacrylate glue to tack everything together before the fiberglassing. I assembled the front and back face then connected them together with the middle struts. I made sure to use a square when gluing and clamping at this part to ensure the sides were level. Next I installed all the side panels and did a rough sand job. Thickened epoxy was used in all the joints and seams to fill gaps. After I had used the glass mat and cloth on all the interior sides I glued the top on. The only way to access the interior now was through the speaker ports. The top was reinforced with two layers of glass and a third layer where the handle would go. You can see this balsa wood box only weighs three LBS but can support me at 160lbs. The outside was finished much like a boat. Slightly thickened epoxy was used as a flood coat and then sanded smooth.
Step 3: Fairing and Finishing
After the outside was as nice as I was willing to make it I did about three coats of primer. The paint I used is called brightside. Sticking with the nautical theme it is a tough polyurethane topside finish for boats, goes on easy and looks great. http://www.yachtpaint.com/usa/diy/products/finishe...
The speakers are Polk audio 6.5. The amp has a built in cross over so I have that set at 90 Hz even though the speakers will go down to 65 or something. It sounds better when its playing at max volume anyway and saved battery.
I used a linear potentiometer and knob I picked up from RadioShack (RIP) and a powered LED toggle switch as a power switch. That's really it for wiring even though the thing feels like it has 9 miles of wire in it. I built a wiring harness that uses clips for everything so it was easy to put together inside the box through the speaker ports. Getting the 12 Amp hour battery through the speaker port was also a task. You can see in the pictures where I had to file some areas back to get the square battery through the round speaker hole.
The last few things were the handle which bolted in and the port for the 3.5mm audio jack.
There are two 7 amp inline fuses on the inside on on the positive from the battery to the amp and one from the rear charging nuts to the battery. You can clip a normal 12v battery charger on nuts to charge it. I normally charge it at 2 amps.
Step 4: Closing Thoughts
This Radio is about 12 lbs. Half the weight of the first radio.
It's also quite loud. The amp outputs 50 watts per channel, or so it claims, at 4 ohms.
The radio will play for a "Long time" about 4 hours at max volume. That's till the amp starts clipping. Also probably doing damage to the battery for draining it that low. It will play much longer at a normal volume.
All in all I am happy with how it turned out. Its a good hybrid of power and portability. The volume of the box is not nearly correct for the size of the speaker but it gets the point across.
Some part files if anyone is interested.