Speakers, part 1

I like to tinker. This may or may not be a surprise to folks by now. My friends know this, and occasionally send me ideas. Friday, as I was starting into work for the day, I got an email from a friend with a link to a gizmodo article.

Long story short, some company in England is charging $600 for this:


Right now I am using a pair of beat up old PC speakers in my shop, and have been looking for something that sounds a little better, has a bit more volume, and is a bit more sturdy. PC speakers usually have 3 watts per channel - they are only meant to work on a desktop, not really a room. The "A-Box" has 13 watts per channel - or 35 watts per channel if you really want to spend the cash. The 25 watt version (the "cheap" one) was still over $400. No freak'n way.

BUT! How hard could it be to build? And thus, every spare minute I had Friday I was of searching the web for parts. Luckily, someone suggested I check out Parts Express. I found 4 inch speakers with a pretty good range (for 4 inch speakers - • Max. music power: 120 watts • Nominal power handling: 25 watts • Frequency Response: 35 Hz to 30 kHz • Sensitivity: 87 dB • Impedance: 4 ohms • Dimensions: 4-1/8" • Mounting depth: 1-3/4")

I found fan grills that would match the mounting holes to the speakers. And I also found these, which are even cooler...


I found several possible amps. But the one I chose was a little 35watt DIY digital amp. It has been years since I actually soldered together an amp, so this really called to me. I even bought a new soldering iron after a friend derided my ancient iron as a "soldering machete."

It is just a simple 2 channel amplifier. But it is very small, and has a remote volume pot. And I get to build it. Even better. The amp has a jack for a 2000ma 12vDC plug in adapter, so I bought one for wall socket use. But a also bought an 8 cell AA battery holder that I am going to solder into the amp, so that I can use it away from house power.

The case is just an old ammo can - used by the military to hold ammunition. Most guys have some laying around somewhere, and DIYers tend to use them for just about anything. A-Box is using 50Cal cans. I have a few of them, but they are actually being used holding stuff, they make great parts holders. I have several 30cal cans that are empty, though. While these are slimmer then the 50cal cans, everything that I ordered will easily fit into the 3.25 inch internal width. The can is actually 3.5 inches inside, but roughly 1/2 inch will be used up with RaaMat automotive sound insulation (which I had on hand from my automotive projects). This is important or else the can will resonate and sound like poo.

I ordered the parts on Friday night after work. My cost was $82. If I had gone with cheaper speakers, the cost would have dipped down into the $60s. However, the cheaper speakers did not have as wide a range.

I vetted ideas through a few forums that I visit, and I have already had people asking me what I was going to use for a sub. At this point, I am not planning to use one. I'd have to use a bigger ammo can, and a different amp. If this project turns out well, I may make a MkII version out of a 20MM ammo can, that has a sub woofer, and a 100watt amplifier.

Part 2 will be the build post, assuming that I get around to building this before the end of the semester.