There’s real magic here, and it can be as efficient as you want it to be [I’m using the Fostex 208ESigma at a reported 97dB/w, but you can get better with more $]

To make it work, you have to resign yourself to four facts.

1. There’s no such thing as a full range loudspeaker
2. The response above, say, 4 KHz, is problematic – you need a tweeter
3. The baffle should be asymmetric, targeting a cut-off of around 200 Hz
4. You need a good woofer from wherever up to 200 Hz. Right now I’m using Altec 3182s sealed, but I think I’m going to try JBL 2225s ported next, unless I can find the money for at least four new drivers for OB bass. Hey, maybe even a Karlson in honor of Freddy.

What you get are the dynamics and immediacy of horns without the colorations. It’s just the best I’ve ever heard, and I don’t think I’m being too delusional. My oldest daughter, an amateur musician with a pretty good ear, told me some of her favorite vocal CDs have never sounded better on any system we’ve had (and she loves to be critical of Dad’s pitiful attempts). I was playing the Stereophile test CD and when the dog on the CD started barking my dogs came running (that never happened before).

All of this, the need to XO to avoid 4 Khz resonances, the use of open baffles for the midrange, big woofers in big enclosures, is described in GA Briggs’ 1950 edition of his loudspeaker book. Had I been paid closer attention to what I was reading, I would have started down this path long ago.

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Dave :^)

You can use the very simple "Edge" program to come up with a baffle size and driver placement. In general you want a rectangular baffle with assymetric placement of the driver.

http://www.tolvan.com/edge/ ("The Edge")

• Crossover Calculators