Here, for example, is a case where bad arguably prevails:
Source: Modern Mechanix blog
No doubt, the person who devised this system in 1931 thought it a brilliant, or at least entertaining, idea. Fortunately, common sense prevailed and the era of the "auto speaker," with its potential to scare the living daylights out of pedestrians, never came to pass.
But here's the thing: equipping cars with external-sounding speakers can be a great idea, when done for the right reasons. For example, some hybrid and electric vehicles are dangerously quiet for bicyclists and visually impaired pedestrians. Adding speakers to emit audible alerts or to project synthesized engine sounds can be just what the doctor ordered. Or rather, what the parliament ordered: earlier this month, members of the European Parliament stated that they want automakers to install acoustic alerting systems in hybrid vehicles by July 2019.
Mind you, safety isn't the only reason to project synthesized engine sounds. For example, fuel-saving techniques can make even powerful engines sound wimpy — a problem when high performance is a key ingredient of a car's branding. In that case, the automaker may wish to project synthesized engine sounds over both external and internal speakers. The speakers can help preserve the car's wow factor (provided they're not too loud) and the internal speakers, in particular, can make it easier for car owners who drive manual to shift gears by ear. The QNX concept car for acoustics offers a good example of this technology in action.
All of which to say, engine sound enhancement, also known as ESE, is here to stay. And it's not a bad time to be in the automotive-speaker business, either.