>>>(2x the sound pressure and a perceived 20-30% or so increase in volume), though I'm not sure it'll be worth the extra hassle and weight.<<<
Three dB, while useful, is not really that much louder. If you ever listen to the radio and turn it up just a smidge that tends to be about 3 dB. It's not overwhelming or anything and may be offset by other factors such as install details. It would be useful to know what our stock horns can do at the 2 meter distance....I think I read that they put out 97 dB but don't have the conditions under which they were tested. The frequencies of the tones also makes a difference with higher freqs falling in the range where they are more noticeable to people for the same dB level. Also the way these horns are measured (dBA) uses a scale whereby sounds below 1000 HZ are progressively filtered off and most of the horns seem to have their fundamentals below 1000 Hz. Further complicating things is that the lower frequencies tend to penetrate barriers such as the next car's window glass more effectively. When I track down my RS SPL meter I'll try to get some numbers on the stock horn. If it is 97 dBA @ 2 meters then either the 115 or 118 versions should be quite a nice improvement. To me the three tone horns sound the best. I have never had air horns last more than 2-3 years so they may just need changing out from time to time. Or maybe the lower mileage many Elises will see mitigates longevity concerns. Some say to make sure they point downward so that water issues are minimized. Also, there tends to be a slight but noticeable lag between when you hit the horn buton and when the sound starts up and reaches full power.
