A Special Tweeter
This is the Ion TW1S tweeter module found in the Acapella High Violoncello II loudspeaker ($80,000/pair). As you can see from this picture, taken in JA’s listening room, the tweeter module rests beneath the Acapella’s midrange enclosure. (That big, purple bell—the color is actually Porsche Amethyst—has a diameter of 18.5”.) Housed in a perforated metal box and powered with its own AC cord, the tweeter module is a completely self-contained unit; it accepts a line-level input from an RCA jack and amplifies the signal with a class-A amplifier.