With the Mozambique, I wanted to create a pair high quality bookshelf speakers that fit in our new entertainment system. The height of the section that houses the speakers is only 12.50 inches, so large drivers are out of the question. I picked the Dayton RS150S-8, a proven driver in the DIY community. I agonized over which tweeter to use, but chose a ribbon for the first time. I researched the pros and cons over weeks, and went ahead with the Aurum Cantus G2Si.

Using 3/4" MDF, the dimensions are as follows: 12"H X 7.5"W X 10.5"D. The volume of the box came to 0.307 cu ft. The vent is 2" long with a diameter of 1.375". F3 is approximately 62Hz. I used 2,600Hz as the crossover point for 2 reasons:

1. Aurum Cantus recommends crossing the G2Si over 2,500Hz with a second order.

2. 2,600Hz translates to a center to center distance of 5.219", the maximum usable distance given the size of the drivers' flanges.

Boy, was it tough! First, I couldn't get a decent measurement from the Woofer Tester II using version 1.04. Keith Larson worked on this for weeks, sending me new beta versions every other week to see if I could come up with usable T/S parameters. His explanations were thorough, but sometimes so scientific that I wasn't able to make sense of the instructions. I wrote to Aurum Cantus in China, and asked if they could email me a full set of parameters. They sent me the same T/S that were posted in their web site. Some help!

I then decided to go back to basics with the help of Jeff B's PCD 2.03, and came up with a textbook crossover using just the frequency and the impedance of the drivers. I added a baffle step correction circuit, and a L-pad to adjust the difference in driver sensitivities. Both the high and low passes now sport a second order Linkwitz-Riley filter. I put the crossover together, and promptly put my new speakers to the test. Sounded OK, not great, rather disappointing. On the test bench, I saw an ugly -5dB dip around the crossover frequency. Flipping the tweeter polarity made the dip worse, so I know I've got it right the first time. After consulting the guys on the PE board, I then decided to increase the slope of the high pass to a 4th order. And that took care of the dip. As you can see from the posted measurement, the frequency plot is quite decent. Impedance runs around 8 ohms or more, so the system is virtually safe for most amplifiers. As for the finish, I used African Mozambique paper-backed veneer for this project.

How does it sound? Quite awsome. To test vocals, I used a good recording of Celine Dion's "My Heart Will Go On". The sound just blew away my panel of semi-experts (wife, older brother, 2 friends). Classical and Jazz excel on these. Small speakers, but incredible sound. Try it for yourself...

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GALLERY - Click to enlarge