Coaxing better quality sound from your loudspeakers could soon be taking a tropical turn. A Japanese paper-making company is helping to develop a speaker diaphragm made from paper that began life as waste banana leaves. Apparently the material has far better sound qualities than conventional materials. Normally made of paper, a speaker diaphragm has to be highly elastic and light enough to move easily when vibrated by the speaker's electromagnet. "We started using waste banana leaves in our traditional paper-making process to make high-quality calligraphy paper,' says Riko Imamura, president, Yamaichi Washi Kougyou Paper Company. "But it turns out that the paper has just the right qualities to make excellent speaker diaphragms, as the fibres are not homogenous.' All diaphragms resonate at a preferred frequency, but the lack of homogeneity in banana fibres may help improve sound quality by cutting down on resonance. Hi-fi firm Akimashi Foster Denki is experimenting with the paper to find out why its properties are so favourable and how to improve them further. Seki Suzuki, of Mitsubishi Electric's speaker engineering division says he is intrigued by it. "Banana fibres may have the characteristic of damping sound,' he says. "That could mean the paper would have a high loss factor.'