Here's the start of the construction phase for my ultimate home theater speakers! At this point, I'd been planning the design in my head for at least a year or two. I wanted something big, for good bass response, yet with a small footprint, and being light weight was also a plus. Of course, it also had to be unique, rather than just a plain rectangular speaker. The cardboard tubes from Cubicon are about the only thing that fit the bill. A similarly sized cabinet out of plywood, particleboard, or MDF, could be quite heavy. Acoustically, at least in theory, a cylinder is better than a rectangle, and the very narrow front baffle (the flat section) helps out the imaging of the speakers. The cardboard is about 1/2" thick and is made by wrapping a continuous sheet around several times until the desired thickness. In this case I think there are about 8 layers. The tubes were expensive, but I think the results are well worth it. They also have the excellent property of a speaker without any right angles! In fact, save for the front section of the oak top cap, there aren't even any straight lines on the outside! My choice of woofer was a closeout from MCM Electronics, a very nice cast frame, polypropylene cone, and rubber surround, 7" driver. They only cost $10 each, but perform like about $30. My ideal woofer would have been the Peerless 850122, or 7" CSX, but at $39 each, that would have quadrupled the cost. The tweeter is an excellent silk dome unit, also from MCM Electronics, the 53-525 (still available), which is +- 2 dB from 2,000-18,000 Hz with an average efficiency of 94 dB. Perfect! The last shot is a preview of the 18 component crossover which sends the appropriate frequencies to the woofers and the tweeter. You also see the threaded steel rods which connect the top and bottom caps.



And now on display, the true guts of the speaker, the crossover! Up to this point, all my crossovers had been very simple, a single capacitor or inductor for attentuation, and maybe a capacitor and resistor for impedance compensation. Since these were my ultimate home theater speakers, I thought I could use some professional help. I had been a friend of Dan Wiggins, the president of Adire Audio, for some time, and he had been giving me oodles of free advice as the design of the speakers progressed. He and David Hyre (the big brain at Adire) even came down to my work at Magnolia one day to measure the response of my MCM woofers before I bought all 10. Once we knew the woofer and tweeter, Dan whipped up the design for my crossover and E-mailed it to me. As you can see, it came out far more complex than anything I'd done, and as a result, much more expensive and time consuming to make. However, I think the results are well worth the effort, as this is by far the best sounding speaker I've ever made. And this is just with the MCM woofers, they get better in my latest iteration, read on! The last few shots are from this year, when I finally got around to visiting Adire Audio and had some frequency response measurements done. As you see in the graph, the response is respectably flat and smooth, within a +- 3.5 dB window from 200-16,000 Hz. It wasn't until 2002, nearly four years later, that I came up with an official name for them:
The Emerald Towers.



If you haven't guessed by now, the cardboard is covered in hunter green velvet. I considered several options for finishing, including stone paint, wood veneer, and wallpaper, before browsing through the fabric store. Paint would have been quite messy, and hard to do given that it was November when I started the project. I thought veneer would just look weird, and also be messy, not to mention expensive. When I saw this hunter green velvet, I knew I had to use it! As fate would have it, it was 40% off that week, what a deal! The trim on the bottom of the speaker is a result of the velvet fabric being a couple inches shorter than the tube. I was able to borrow my Aunt Jeanne's sewing machine, and my Mom made the velvet socks. I also must give credit to my brother Ben and his wife Jeannie, for letting me borrow their garage for an entire weekend to do all the wood cuting. Thanks again to Dan and Dave from Adire Audio, too, without whom I'm sure these speakers would not be nearly so excellent!



My upgrade, just done in October 2002, was replacing the woofers in the front left and right speakers with one of the best 7" woofers on the planet, the Peerless 850122, also known as the 7" CSX. I decided to change the speaker from a sealed box to vented (sometimes called ported). I was expecting an improvement in the bass response as well as a smoother frequency response. What has resulted far exceeds any of my expectations! As predicted, the bass is better than my subwoofer. The vent is tuned to about 22 Hz, which results in a nearly flat response down to 30 Hz in a typical room, with the capability to play LOUD. In addition to the awesome bass, an equal improvement has been made in the level of detail. I'm hearing new things in the music of just about every song, I have to keep checking that nothing is wrong! They were great speakers before, now they are truly amazing! Oh, and again as fate would have it, the new Peerless woofers fit perfectly, even the screw holes lined up. Perhaps some day I'll replace the other six MCM woofers with the Peerless. But for now, the front two speakers give me more than enough bass output, and the set of five are still a fairly close match to each other, sonically.