Here are some pictures of a pair of 40hz horns I built for Jon Ver Halen (Lowther America) for the 2003 VSAC show. They were completed in two weeks - the fastest I've ever built speakers, especially with a finish. They use Lambda TD15M Apollo woofers (15" woofers with a large faraday ring and a phase plug). They should cover 40Hz to 350Hz in typical loading situations, but more experimentation is currently needed.These horns were originally designed to use a JBL 2226 woofer. The horns I built were converted to use the JBL drivers after the VSAC show and no difference was heard or measured. The Lambda drivers were used in the first pair of horns because they were what Jon had, and modeling showed that the performance should be about the same.