It’s coming together! I’ve been working pretty hard these last few months on coming up with the best possible design for this boombox. It looks like there are basically going to be two models: a smaller one (13″x5″x8″) with 4 full-range 3″ Aurasounds and a 5.25″ passive radiator…
(like the one above, built for my friend Jamie) and a larger, louder version with 2 6″ woofers, 1″ titanium dome tweeters and a custom crossover, with an 8″ passive radiator. It’s about 21″x9″x5″.
(this is my unpainted prototype, a test model that I load up with different batteries and amps to see what works and what doesn’t. It actually has a different setup than the new-new one, right now it has 5.25″ full range car-door drivers with mylar tweeters and a simple capacitor in lieu of a proper crossover.)
These things both have a balanced, punchy sound with good low-end extension and can be incredibly loud for their size. It’s a bunch of good components, in a box that’s designed and built right, and although they’re not supercheap to make, they don’t sound cheap either. The market’s saturated with stuff that sounds like crap and I don’t want to add to that pile! I get a lot of “wow, really?” when people hear it and that’s been the motivation to keep improving it. We can do better!
The “San Quentin Execution Chamber Green” box, above, was an experiment that only sort of succeeded. I’d heard good things about those Aurasound drivers and wanted to see how they would sound without tweeters. Turns out they sound great, and have this amazing low end, but they’re predictably a little dull by themselves. Overall, the sound is natural and very clean, even with the volume cranked all the way up. The thing puts out a lot of sound and the PR makes the most of the extended lows on the Aurasounds. I’m going to swap out the top two in favor of some different full-range drivers that can handle the 14k+ range a little better and we’ll see how that works.
The amp has been the weak link. The TA2024 chips I’ve been using sound great, but pushing 4 ohm loads they start to break up before the speakers do. I’m switching to a more expensive TK2050 chip, which should resolve this. Another cool bonus with this amp: although it will happily run on 12v like the TA2024 does, it will accept anywhere from 9 to 24 volts and will put out a good deal more power with higher voltages, so I may put a separate DC jack on the back of the unit–if you want to run it directly off the 18v power supply, you’ll be able to get more out of it. Good for whenever there’s an AC outlet around. (For example, I’ve taken this box to a few DJ gigs at venues without monitors. It’s awesome for that.)
Batteries have been a headache too, but I’ve settled on a custom LiFePO4 pack. LiFePO4 batteries are cool for a few reasons–they have a much longer lifespan than the standard consumer-electronics LiCoO2 battery you’ll find in laptops and phones (these LiFePO4 cells are rated for 2,000 full cycles before an 80% capacity drop, LiCoO2 batteries are usually rated around 500.) This means a lot less waste and a lot less money. LiFePO4 batteries also keep a very constant voltage until they’re almost completely drained which means performance won’t droop as the battery is discharged. They also happen to be a lot easier on the environment than LiCoO2 packs when they eventually do crap out. Oh, and the whole lithium-batteries-just-explode-sometimes thing apparently doesn’t happen with LiFePO4 cells. The one drawback? They’re a little bigger and a little heavier, but we’re only talking a few ounces for the size pack we’re using.
I tried a handful of these cheap $30 too-good-to-be-true lithium battery packs from Ebay that ship in little packets from China. They suck. They die, their capacity is nowhere near advertised and they won’t even hold a charge after a few cycles. I got a kick out of this disclaimer from the distributor, for a 6800mah battery:
So….sure, we lie about our products, but only because everybody else does too!
Last week the ladies of SoulCycle rented my prototype box for an outdoor dance video shoot. Apparently even the old TA2024 amp had plenty of power. I included a Bluetooth thing so they could stream music from a cell phone. It’s a cheap device, only about $30, and it works great.
I’ll be working out kinks in these over the next few months and should start to have these available for purchase in the spring. If you’re interested in getting one or just seeing how the project develops, sign up for the mailing list here or send an email to firstname.lastname@example.org.