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As mentioned earlier, my primary goal was to build these speakers out of only parts I had laying around, no trips to Lowe's or Radio Shack allowed! I did have some particleboard on hand, but knew it would take much more time to build a cabinet from that, especially since my only saw is a jigsaw. The pots allowed extremely fast build time, the proper color, and are unique, a Gilbert speaker trademark. They also have provided the benefit of tilting the speakers back, which may help with the imaging by aligning the woofer and tweeter axis' better. The vents (ports) are toilet paper tubes, which where a little shorter than I would have liked, but hey, these are only for my desk at work. The tubes have been stiffened by none other than the universal fix it, duct tape! Yes, you actually can use it on ducts! The tweeters I have had nearly 12 years and have served in many projects, but have been unusued for the past five years or so. I won the woofers at an amateur loudspeaker gathering in Canada during November 2002. The wood was extra material from my Emerald Tower upgrade project. These are 14.5", and I decided to go with the 18" rounds on my ET's. The simple crossover consists of a single capacitor and inductor, which give the tweeter a second order (12 db/octave) electrical filter at approximately 3,000 Hz. The woofer runs full range, but based on it's response graphs, it starts to smoothly roll off at approximately 2nd or 3rd order around 3,000 Hz. A gold plated input terminal, some wire, and rubber feet to plug the holes in the bottom of the pot round out the small parts list.



Here you see the woofer, tweeter, and port mounted to the front baffle. I had no stain or oil around my place, so they will go unfinished for the time being. I also screwed up a couple times on the measuring and cutting of the holes for the woofer and tweeter, so each speaker is slightly different in that regard. Soon enough I'll have a house instead of an apartment, so I can get set up with the proper tools for the job, namely a router with a circle jig, and a drill press with a circle cutter! I was going to glue/caulk the large pot directly to the baffle, but my three year old caulk had frozen up on me, and the hot glue just didn't seem to want to stick by the time I got done going all the way around the 14" pot! I decided to just screw it onto the baffle with six screws, and that actually seals the 'cabinet' remarkably well! I don't currently have any stuffing inside the pots.

So what are the results? Well quite frankly, I am amazed at how good they sound! Due to the vented cabinet and small size and excursion of the woofer, it's fairly easy to overdrive them with really low bass. However, they play surprisingly loudly and cleanly above the tuning point, which in theory is somewhere in the mid 40 Hz range. High power level testing with the signal generator at work revealed no obvious leaks or defects in the enclosure. Playing actual music containing heavy bass material, the lack of vibration on the cabinet walls is quite impressive, especially considering just how thin the pots are! While not exceptionally accurate in the bass response, it does have quite good low end extension, considering that it's a 6.5" woofer in only 0.4 cubic feet. The midrange I feel is quite good for what is normally an $18 woofer (free to me!), and the treble is naturally great, as these tweeters have been highly regarded for well over 10 years. It's a little bright sounding because the tweeters are a few dB more sensitive than the woofers. I later added a resistor inline with the tweeter that fixed that problem.

Updated January 17th, 2004!



There was a second amateur loudspeaker builder's meeting in Surrey, B.C. (Canada, eh!) in November 2003. Seeing as how I won the woofers for these speakers at the same event in 2002, it was only natural that I would bring them to the event. I can't recall getting numerous compliments on them, but at least no one came up to me and said they sucked. However, now that they had been displayed and auditioned in their original no-cost form, I felt it was finally time for an upgrade. I replaced the aging (and damaged) Vifa aluminum tweeters with some compact soft dome tweeters from Morel, the MDT-12. The crossover was simplified beyond it's already basic state, and now consists of a single capacitor of about 8uF. Ok ok, so it is two capacitors in parallel! I naturally obtained new pine rounds for the front, which I finished in cherry stain and Meguiar's paste car wax. I added some self adhesive damping sheets to the inside of the large pot, and completely stuffed the rear pot with polyester fiberfill. The port was relocated to the back, and was changed from the original toilet paper roll to 2" ABS pipe. The straight section is 9" long and the flare is simply a 2" to 3" coupler, which is roughly 3" long. These ports really do justice to the Power Pots name! As you can see, the inner end of the port is only about 1" from the woofer's magnet assembly. I think I have read somewhere that such a location is a bad idea, but so far I don't hear any problems. Finally, a pair of binding posts was added on the bottom. Despite the extra parts, the project still was mostly low cost and limited store trips. The only extra parts I bought were the sheet of damping material, and the new front baffle. The tweeters I had for well over a year, originally planned for installation in my car. The capacitors, binding posts, and polyfill I scavenged from the spare parts bins at work.



So, now that the speakers have a more finished appearance and hopefully better sound, I felt it was time to make some proper stands for them. Plus, with the port now in the back, they are no longer appropriate for sitting on a desk or shelf. Naturally, the stands had to be just as unique an appropriately colored. I toyed around with several ideas in my mind before I remembered that I had some cubicon D-tube and green velvet left over, not to mention the old fronts from these speakers. All I had to buy for the stands was some miscellaneous brass hardware and a 4 x 4 to make the post. The speakers do not physically attach to the stand in any way, they just sit on top. They are fairly stable, more so on solid ground than heavy carpeting. They let the speakers tilt back slightly, which in theory could improve the sound due to better time alignment between the woofer and tweeter. You can see how they compare next to my Emerald Towers and Emerald Titan. I'd keep them in the front room, but there is just no space! However, they make a great extra system in my guest/exercise room, seen in the final picture.

Again you ask, how do they sound? I am almost sorry to say that they sound better now than my Emerald Towers, at least above about 100Hz. Their bass extension isn't as good as the ET's, but the cabinet IS 10 times smaller. On the other hand, the Power Pots actually take up more floor space the the ET's. The bass with the new port is certainly a vast improvement from the bass of the original design. There is no port noise to speak of, except using test tones with very high levels and low frequencies. Low end extension is pretty good, smooth down to about 40Hz. The biggest improvement though is simply in the quality of the music. There is much more high end detail, yet the sound is never harsh or bright. Everything just sounds more alive, more real, and with many recordings you would almost swear the musicians are right there in the room with you. The imaging is the best I have yet heard from any of my speakers, placing instruments and people in very specific locations in the sound field. The speaker really do sonically disappear on good recordings. I'll be getting some frequency response measurements in the near future, which should let me know if the increased detail and some other benefits can be attributed to a high end that is elevated more than it should be. However, the bass improvements, and I suspect the imaging and liveness improvements as well, should remain regardless. If I were to actually buy all the parts needed to build these speakers, not counting things like stain and screws, it would only come to about $130. For that price, the sound is truly amazing. The stands would be extra, but you don't have to use my Emerald Stands.


Here's the parts list with approximate total prices for the pair: