Driving a convertible is one of life's great joys. Driving a drop-top gives you, as John Denver once noted, sunshine on your shoulders. And that makes you happy.

Putting the top down also gives you gobs of wind and noise, which makes it hard to jam out to Carly Rae Jepsen or your summer tune of choice. That's why Mazda and Bose have developed a new stereo for the 2016 Miata that takes into account whether the top is up or down and optimizes the sound accordingly.

Of course, this wouldn't be a proper auto industry announcement without buzzwords and trademarks like the "UltraNearfield" speakers installed in the headrests and "TrueSpace" technology that's basically a processor that makes music sound better in a car.

Fancy words aside, it takes serious audio smarts to build a stereo that sounds good in a car, let alone a convertible. Bose and Mazda have been working on the system for three years, testing in a previous generation Miata in real-world, open-road environments.

Mazda

With the top down, the stereo's equalizer compensates for the very different acoustic environment compared to an enclosed cabin. There are effectively two very different equalizer settings depending on the status of the roof. "It's a completely different listening environment [with the roof off] compared to when the top is up and the cabin is closed," says Kevin Doak, a spokesperson for Bose. "We completed two separate equalizer tunings... and programmed it to recognize the different conditions."

Cabin-mounted microphones (part of Bose's AudioPilot 2 noise compensation technology) recognize how noisy the car's interior is and adjusts the music to overcome outside noise. Speakers in the headrest—music closer to your ears—aren't new, but now the car packs signal processing magic. That creates a "sound stage" around your head, making the music seem as if it's coming from much farther away, but still easy to hear. Bose says this makes the listening experience "enveloping and spacious."

The result is a high-tech step above the old system: cranking up the volume.