Next time you're trolling the lots for $25,000 worth of new-car smell, consider this: A quieter car is the best car-stereo upgrade you can buy. While pounding down the interstate at, say, 70 mph, today's mid-market sedans and coupes maintain a reasonably quiet cabin somewhere between a Lexus-like 67 dB SPL and a Mustangesque 77 dB SPL, measured at the driver's head.
Either extreme is acceptably quiet to most casual drivers (though at least 20 dB noisier than your average living room), but for car-fi considerations, 10 dB is an enormous swing. Assuming identical speakers in each car this means that the Mustang would require a whopping 300 watts per channel to get the same musical dynamic range that 30 watts watts per channel nets in the Lexus.
Quietude brings other musical fringe benefits: The masking effects of the typical car's noise spectrum dominate the midrange and bass regions, and in truth no amount of power can fully compensate for them. So the less noise, the better. A quieter car also means lower-output operation, which in turn permits amps and (especially) speakers to work less hard, for significantly lower real-world distortion (particularly at low frequencies) and, in all likelihood, longer lifespans. If actual musical quality is your goal, a silent runner is the best place to start.
