When you’re listening to speakers, it’s easy to fall hard for high-end sparkle and big, gut-punch bass—and those are definitely important. But how much attention do you pay to the middle of the frequency range? That range, between about 300 Hz and 5 kHz, contains most of the audio content in music, movies, and TV shows. Compounding that, humans don’t perceive all frequencies as being equally loud; we’re much more sensitive to upper-midrange frequencies, especially those around the 2 kHz to 4 kHz range. For these reasons, midrange frequencies are critically important when it comes to reproducing the clarity and separation of instruments and voices in the mix. In order for a driver to accurately reproduce sound, it needs to move consistently and efficiently. But the bigger the driver, the harder it is to control. When cones are pushed hard they can start to flex and exhibit resonances; this phenomenon, called “break up,” creates undesirable sonic artifacts like sharp peaks and ringing....