Jethro's World

**WARNING: AUDIO GEEK POST**

What do you do when greeted with rain on a Saturday morning? That's right, you tinker in the garage.

Todays project was one I had been contemplating for some time... ever since this box of 22 little speakers (known as NSB's, short for No Stinking Badges) mistakenly landed on my doorstep. Noah has been asking for a stereo in his room, and I was just dying to build him some little speakers to go along with my old Denon 2-channel receiver and single disc CD player.

I had considered also using some larger speakers to fill in the low-end, but in the end I opted to run a pair of NSB's per side... a sort of 'mini-array'. I didn't have the crossover parts on hand to get a good match between the drivers, and I didn't want that large of a cabinet sitting on the dresser. I decided that I can always add a little sub later if he starts asking for more bass.

I measured the drivers with my Woofer Tester, and then modeled response in BassBox (a computer program that models frequency response). I decided on a small .08 ft^3 cabinet stuffed with poly-fill... frequency response graphs show a couple dB bump right around 200 Hz, and then rolling off rapidly below that. The very low inductance made for a nice model on the upper end of things... showing usable response well out to 5 Khz+ (still, these were just models, and I was a little skeptical of the upper end response).

The actual exterior cabinet dimensions are 10.25"H x 5.5"W x 5"D. My total cost for the project: $0.00. The box is built from scraps. The speaker wire was leftover from a project last summer (a customer paid for it). Polyfill and screws are from other projects.

A close up of the NSB 'mini-arrays'.

We plan to fill screw holes and paint the cabinets eventually, but I wanted to make sure they sounded OK before I went to all that trouble. I will let Noah choose the paint color. :-)

Noah had to listen to one of his CD's at first, but then it was time for me to try some of mine. I popped in my Pat Coil CD to do a quick test and was very pleasantly surprised. I was afraid that the bump @ ~200 Hz was going to cause problems, but I really can't say that I noticed it. The rapid rolloff below that point was very much evident, though. I was most impressed with the upper end extension of these little guys... I'd easily surpasses the performance of the *cough*BOSE*cough* (audio 4-letter-word) Twiddlers. Cymbals were crisp and the overall image was actually very good. The midrange seemed to get a little overwhelmed with complex passages, but I won't really complain considering the cost.

It was a fun little project... and it was especially fun having Noah out there 'helping' me. :-) And he couldn't be happier with his new stereo...

Noah's stereo.