Still, combined with the rerouting of the exhaust outlet through the pump cavity, a change that was made on all of Sea-Doo's boats last year, the casings and insulation alone would offer a significant drop in sound levels compared to past models. For 1999, the casing has changed some - the material is a new rubberized plastic and the casing is split vertically rather than horizontally for easier assembly. Other aspects of the total system have been easier to transfer to each model, however, including the insulation and casing on the mufflers and the various composite parts used in the engine. (On the GSX models, they've only been able to squeeze one four-tube resonator, while on the GS and the GTi, they have only one three-tube resonator. On the GTX models, Sea-Doo has been able to squeeze two lower four-chamber resonators into the footwells, which in turn offer the greatest reduction in sound. The waves bounce off the back of the tubes and then cancel out incoming waves, thereby suppressing much of the noise at those specific frequencies. These resonators are designed to suppress specific low frequency sounds and look something like the pipe area on a pipe organ, with different length tubes attached to the exhaust pipe into which sound waves pass. There are a number of reasons for the variance, but one of the biggest is that available space in the engine compartments has limited the number of Hemholtz Resonators Sea-Doo can fit in the different models, and the Hemholtz Resonators are at the heart of the D-Sea-Bil system. The system does it by borrowing a variety of different techniques and technologies from the automotive industry to reduce the sound level on all of the models in Sea-Doo's lineup.ДЄlthough not all models will get the same amount of noise reduction, each will offer significant improvements over last year. From a public relations standpoint alone, the D-Sea-Bil system helps everyone involved in the market from consumers to Sea-Doo's competitors because it addresses the major complaint from the public at large against personal watercraft - noise levels. Sea-Doo deserves a great deal of credit and praise for the inclusion of the D-Sea-Bil system on all of its boats this year. There's more change here than meets the eye. So scoff all you want and say the new Sea-Doo lineup is only more of the same. It may not be a large, dramatic one, but it is another step toward meeting and exceeding the stricter EPA standards that are coming up. In fact, Sea-Doo engineers estimate the individual models are anywhere between 10 to 30 percent quieter than last year's models, and who knows how much quieter than models from three or four years ago.Д¬onsider, too, that Sea-Doo now has a second model with electronic fuel injection and has improved the fuel economy and reduced emissions throughout its lineup by fine-tuning the carburetion and calibrating the jetting on all the various models. Since all nine models in the lineup now include the revolutionary D-Sea-Bil sound reduction system, Sea-Doo now boasts the quietest lineup of personal watercraft ever assembled. On top of that, the only new model in the lineup - the GSX RFI - isn't really all that new since it runs on the three-year-old GS platform and uses the same fuel injection system that debuted on the 1998 GTX RFI.Д«ut forget about brand new, never-seen-before technology for a moment, and consider the 1999 Sea-Doo lineup from a long-range perspective. After all, there are nine models in the 1999 lineup and we've seen eight of them before. You cynics out there can pass the 1999 Sea-Doo lineup off as more of the same-old, same-old.

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