Boombox, field tests

A short addition for this project.. The part where I get to do a quick field test rating for my workmanship!

Mmm yes, back to the drawing board.

Whilst attaching the locking clip pictured above, I had to change its position once. This left extra holes in the particle board which in turn weakened it up. No wonder, that once out in the open and hitting a _serious_ bump with the trolley, the board fractured.

Other than this, field test turned out ok. Smooth grooves got played and the lovely sunny afternoon was shared with a bunch of friends. Needless to say, the beer was good too ;)

Out in the open!

Reckon I’ll revise the location of the locking clips a little and then proceed with testing.

Boombox

Info

Trying to figure out a use for a car battery, Boombox was what I ended up with. Here, the battery is used to power a audio amplifier and accessories connected through an auxiliary cigarette lighter jack (f.ex. a peltier-cooled freezer bag). The Boombox has 6″, 4″, 2″ and 1″ speakers elements two of each, driven by a Lepai LP-168HA amplifier. This provides separate gain stages for bass (50W RMS) and treble (20W RMS) speakers with adjustable crossover and level controls per gain stage. Treble gain stage has also separate bass and treble level controls.

6″ (bass) elements are housed on separate compartments (front and rear). Front 6″ is sealed type whereas the rear 6″ is reflex type. The amp has both 3.5mm and RCA inputs and also a +5V USB power connector. The 3.5mm and USB connectors are routed to a iPod dock located in the front panel, allowing a single connection for both playing audio and charging devices equipped with Apple’s proprietary iPod connector. To add a bit of decoration, there are loudness controlled EQ visualizer transfers on both sides of the enclosure. Project completed in 2011.

Work stage posts

Part 1, background, ideas and speaker analysis

Part 2, enclosure design

Part 3, 6″ compartments

Part 4, side panels & EQ visualizers

Part 5, assembling what’s left

Part 6, final touches

Pictures & Video

Boombox, part 6

Final touches, not much to it.. :)

Amp all wired up, USB power adapter installed to cigarette lighter socket.

Boombox, part 5

Uh, where to begin..? Certainly been lazy with any updates, but quite the opposite with building this ‘thing’ :). Lots of small issues sorted out, plenty of adapting on the fly as well as some amount of re-do, all (finally!) mounting up to a point where the Boombox actually started making noise!

I sure can’t recall the details of even half of all the work I’ve put in, but picking things up from last time, let’s start with the analyzers. I ended up adding a separate 3.3V switch mode DC/DC converter board for them and housing everything inside a small junction box. The analyzer boards used a 10k linear potentiometer for sensitivity adjustment and thus, wiring both to a single stereo potentiometer seemed like a good idea. Too bad I had only a logarithmic potentiometer at hand so as it is for the time being, the adjustment is a bit tricky. Will replace this once I have the proper part.

Boombox, part 4

Status update..

6″ compartments are shaping up neat. Two layers of paint have been applied, so what little remains to be done is mainly the wiring chores. I’ll wait with this until I have the treble compartment ready to be wired up too. As a neat little extra detail for cabling through-holes, I now have some rubber grommets. These were sourced from the Panasonic speaker enclosures, where they were used to attach the decorative fabric in front of the speaker.

Rubber grommets, just loaded with high re-use value!